SmartFrame Subfloor Design Guide - Tilling Timber

SMARTFrame 

Sub-Floor 

Design Guide 

STRAIGHT AND TRUE 

PRACTICAL 

HIGH AND DRY 

Sub-Floor 

System 

SERVICE FREINDLY 

COMFORTABLE 

STRONG 

2010

SCOPE OF THIS PUBLICATION 

This Design Guide and Load Tables assist in 

the selection of SmartFrame product for 

the common structural arrangements for 

subfloors encountered in domestic 

construction. It is made up from extracts 

from the full Design Guide of each separate 

SmartFrame product, but reproduces and 

consolidates only those parts and sizes that 

relate specifically to sub-floor construction. 

Methods of developing lateral restraint and 

providing adequate support, adequate 

anchorage against wind uplift, and overall 

structural stability are outside the scope of 

this publication. 

Information on the above matters can be 

obtained from AS1684 Residential timberframed 

construction or from a structural 

engineer experienced in timber 

construction. 

Tilling Timber Pty Ltd have structural 

engineers on staff who can be contacted 

for advice on matters concerning the use of 

its SmartFrame engineered timber products 

in timber construction by telephoning the 

SmartData Customer HelpLine on 1300 

668 690 or e-mail at 

smartdata@tilling.com.au. 

SUBSTITUTION OF OTHER PRODUCTS 

All load tables in this document are 

designed using the characteristic properties 

of SmartFrame product manufactured by 

quality Australian and overseas producers 

and distributed by Tilling Timber Pty Ltd. 

COPYRIGHT 

Copyright of this publication remains the 

property of Tilling Timber Pty Ltd, and 

reproduction of the whole or part of this 

publication without written permission from 

Tilling Timber Pty Ltd is prohibited. 

Information relating to CONCERTINA FOIL 

BATTS is reproduced with permission from 

Wren Industries Pty Ltd. No responsibility is 

accepted by Tilling Timber Pty Ltd for the 

accuracy of the stated R values, fixing 

methods or effects of installation of the 

FOIL BATTS. 

CERTIFICATION 

As a professional engineer, qualified and 

experienced in timber engineering, I certify that 

the use of the SmartLVL 15 members as 

shown in these tables, and installed in 

accordance with the provisions of this Design 

Guide, complies to the Building Code of 

Australia. These span tables have been 

prepared in accordance with standard 

engineering principles, the relevant test 

reports and Australian standards, ie: 

• AS 1684.1 Residential timber-framed construction 

• AS 1170.1 Structural Design Actions – Permanent Imposed 

and other actions 

• AS 1720.1 Timber Structures - Design Methods 

• AS 4055 Wind loads for Houses 

• AS/NZS 4357 Structural Laminated Veneer Lumber 

• AS/NZS 4063-Timber-Stress-graded–In-grade strength and 

stiffness evaluation 

CRAIG KAY PEng,EC-1961,RPEQ5100, BPB0730,NPER 

National Product Manager - EWP 

SmartFrame Product Warranty* 

Tilling Timber warrants that it SmartFrame Engineered Wood products will be free 

from manufacturing defects in workmanship and material. 

In addition, provided the product is correctly installed and used, Tilling Timber warrants 

the adequacy of its design for the normal and expected life of the structure. 

This warranty is backed by the full resources of Tilling Timber, Pacific Woodtech Corporation 

and by underwritten product liability insurance. 

Tilling Timber Pty Ltd 

Head Office and Manufacturing 

31-45 Orchard Street 

Kilsyth Vic 3137 

Ph: +61 (0)3 9725 0222 Fax: +61 (0)3 9725 6569 

Email: smartdata@tilling.com.au 

*Abbreviated Warranty - for full warranty document see www.tilling.com.au 

SmartFrame Sub-floor Design Guide 1

THE MANY BENEFITS OF A SmartFrame SUB-FLOOR 

SUSTAINABILITY 

Anybody would think that sand, limestone, silica, iron oxide and alumina 

and steel mesh for concrete slabs “grew on trees” by the claims their 

proponents make regarding their “green” credentials. Trees are the 

ONLY renewable building material, and as they grow, they actually 

REDUCE the atmospheric greenhouse gas, Carbon dioxide. The same 

cannot be said for any of the other materials in a concrete slab. 

SmartFrame 

SUB-FLOORS ARE 

SERVICE FRIENDLY 

Under floor ducted heating is the quick method of heating your home, which reacts quickly 

to changing weather conditions. It is easy to run the heating system components under 

the floor, and even sight the heater unit out of site and away from harms way. Plumbing, 

water supply and electrical services can easily be accommodated under the floor, and 

unlike slabs, can be added to or altered during the life of the building. It is ONLY with a 

raised sub-floor that items such as water saving under floor rain and grey-water tanks or 

bladders can be fitted to either new or existing homes, allowing maximum usage of 

precious back yard space. 

TIMBER FLOORS 

LOOK AND FEEL 

WONDERFUL 

The look and feel of a solid timber floor system adds warmth and beauty to the whole 

house. Timber enhances the quality of your lifestyle. A polished timber floor is not only 

practical and easy to clean, but becomes part of your décor. 



COMFORTABLE 

SmartFrame sub-floors are easy on the legs because they act as a shock absorber, i.e. 

they have some “give’’. A person on their feet all day often experiences tiredness and 

sore limbs if they have been on hard surfaces all day. 


SUB-FLOORS 

REDUCE 

LANDSCAPING AND 

DRAINAGE COSTS 

SmartFrame sub-floors reduce the need for expensive and potentially damaging 

earthworks and drainage on building sites. By adopting the SmartFrame sub-floor 

construction, the preservation of waterways, natural water runoff, rock outcrops and 

other natural features can be assured. Further, underground water flows and evaporation 

of ground water is not disturbed. Unlike many other floor systems, SmartFrame sub-floors 

are the environmentally friendly alternative. 



HIGH AND DRY 

SmartFrame sub-floors on stump or pier systems are OFF the ground and away from 

damp. This greatly reduces the risk of rising damp and flash flooding. Living off the 

ground allows a continual airflow under the house to assist in maintaining a comfortable 

dry floor. A poorly protected or faulty slab can absorb moisture. Problems that may 

occur include moisture damage to external and internal cladding materials, carpets and 

other coverings. 



PRACTICAL 

SmartFrame sub-floors are easily adaptable to split level designs, with alterations and 

extensions able to be carried out with minimal disruption to the block. On sloping land a 

SmartFrame sub- floor can enable owners to create valuable under floor storage. Ideal for 

storing garden tools and even that wine collection. 


SUB-FLOORS and 

TERMITE CONTROL 

Termites love damp soil and can nest beneath a concrete slab. It is impossible to lift the 

slab to check and carry out regular inspections. SmartFrame H2 sub-floors built off the 

ground allow for regular inspections to detect any evidence of termites before they get 

into the home. 


GENERAL INFORMATION - ABOUT FLOOR PERFORMANCE 

The “feeling” that is identified when a person walks on a floor 

is very subjective. Some people want to feel a very stiff floor 

and others want some ”give” so that it softens the footing. 

When people say the floor “bounces”, it may be vibrating. 

This sensation is often caused by lack of dead load such as 

furniture, direct applied ceilings or other materials to absorb 

or dampen the vibration. 

The allowable spans shown in the tables of this manual have 

been designed to meet the strength and serviceability 

criteria in AS1684.1 . 

FACTORS THAT CAN AFFECT FLOOR 

DYNAMIC PERFORMANCE. 

• The choice of flooring system 

• The depth, stiffness and mass of the joists 

• Spacing of joists 

• Fixing of sheathing to joists 

• Stiffness and mass of floor sheathing 

• Mass and stiffness of ceiling materials 

• Method of installation 

• Location and type of internal partitions and furniture 

FACTORS THAT CAN IMPROVE FLOOR 

DYNAMIC PERFORMANCE 

Glue-nailed floors will perform better than floors 

secured by nails alone. 

Deflection of the sheathing material between joists can 

be reduced by decreasing the joist spacing or using a 

thicker and/or stiffer sheathing. 

Proper installation is essential for dependable 

performance. Adequate and level support for the joists 

is necessary, as is correct fastening of the joists and 

sheathing. 

The installation of a ceiling to the bottom flange of the 

joists. 

Between joist blocking can provide some improvement 

to floor dynamic performance. It is emphasised that for 

between joist blocking to be effective, it is important 

that the blocking is continuous, this being easily 

achieved by the addition of a continuous bottom strap 

such as hoop iron strapping which is also attached to 

the end walls. 

If floor dynamic performance is a concern to either the 

client, designer or contractor, then the above variables can 

be altered to improve dynamic performance. Some stiff 

floors with very little dead load may tend to vibrate. This can 

generally be dampened by directly attaching the ceiling 

below the underside of the joists. Where there is no lining to 

the underside of the joists, it is recommended that between 

joist blocking be utilised to dampen this lightweight floor. 

If between joist blocking is to be used to improve floor 

dynamic performance, it is recommended that a blocking 

system (at least midspan, 1/3 points for large open rooms) 

similar to the one shown below should be adopted: 

BETWEEN JOIST BLOCKING FOR SmartJoists 

Floor sheeting glued AND nailed 

to joists and blocking 

SmartJoist between joist blocking, 

skew nailed with 2.8 x 60 mm Nails. 

0.91 x 25 mm galvanised mild steel strap 

fastened to joists, blocking panels and END 

WALLS with 40 x 2.5 mm galvanised nails. 

SmartJoist 

floor joists 

DEEP JOIST BLOCKING OF SmartLVL 

AND TEMPORARY SUPPORT TO PREVENT 

JOIST ROLLOVER DURING 

CONSTRUCTION 

D 

W 

End trimmer to 

all cantilever 

joists 

Temporary restraint 

to link top edge of 

joists during 

construction 

W 

Temporary restraint to 

link top edge of joists 

during construction 

D 

3.6 metre maximum spacing of blocking 

pairs with temporary top edge restraint 

Additional temporary restraint 

to link top edge of joists and 

blocking pairs at a maximum 

of 3.6 m centres during 

construction for joists 

with D/B > 6 


5 STAR ENERGY RATING AND SmartFrame SUB-FLOORS 

The introduction of the 5 Star Energy Rating Standard on 1 

July 2004 in Victoria means that all new homes in Victoria 

will now be more energy and water efficient, this measure 

designed to reduce greenhouse gas emissions and reducing 

our demand upon precious water resources. 5 star homes 

should also save home owners money on their heating, 

cooling and water bills. 

The process of achieving a 5 Star rating is quite flexible, and 

while there is no single formula for obtaining a specific 

energy rating, a range of features can be used. These 

include: 

i. Building orientation 

ii. Wall/ceiling insulation 

iii. Window type 

iv. Size 

v. Positioning 

vi. Shading and thermal performance 

vii. Floor products/insulation 

There has been a popular misconception that homes with 

raised timber floors cannot achieve the 5 Star standard. 

This is incorrect, houses with timber floors can meet the 

standard. This means that you can continue using this 

traditional, easy, and often more cost effective mode of 

construction while enjoying the benefits that SmartFrame 

sub-floors offer. 

The approach to successfully designing an energy efficient 

lightweight house with timber flooring will be different to the 

approach that works best for a design with high thermal 

mass, such as double brick on a slab floor. 

Good building practice suggests that draughts should be 

minimised wherever possible. Typically, R3.2 ceiling and R2 

wall insulation levels may be needed. 

Good window design is important for all 5 Star houses, 

particularly those with timber sub-floors. 

• To minimise heat uptake in summer, east or west 

facing windows may need to be shaded from the 

summer sun with eaves or blinds. 

• For winter, a number of energy efficient options 

are available: 

i. Thermally improved windows for some or all 

windows. This included the choice of window 

frames used and/or the type of glass. For 

example, double-glazing can drastically 

reduce heat loss. Using double-glazing also 

overcomes the need to reduce window sizes 

particularly on south facing windows. 

ii. Maximise north facing glass to increase 

winter heat build up, provided it is shaded in 

summer with awnings or blinds. 

Tailoring the design to the site and orienting the house to 

make use of the winter sun are also particularly useful in 

achieving an energy efficient 5 Star outcome. 

This document is not intended to be an exhaustive reference 

on the 5 Star standard, but is intended to give advice on 

what Total R-values (R T ) a SmartFrame sub-floor system 

correctly fitted with certified insulation systems will provide. 

For general information please visit http:// 

www.5starhouse.vic.gov.au/5_star_house_know.htm 

For more information on the 5 Star building regulations visit 

the Building Commission website at 

www.buildingcommission.com.au or call 1300 360 380. 

For more information about designing a 5 Star house and 

energy rating training and accreditation, visit the 

Sustainable Energy Authority website at 

www.sustainability.vic.gov.au or call 1300 363 744. 

For specific information on the insulation of timber subfloors, 

refer to FWPR&DC Project No PR05.1014 

“Insulation solutions to Enhance the Thermal Resistance of 

Suspended Timber Floor Systems in Australia” available from 

www.fwprdc.org.au. 


5 STAR ENERGY RATING AND SmartFrame SUB-FLOORS 

To enable designers of SmartFrame sub-floor systems to 

assign Total R-value R T the floor for input into energy rating 

programs or manual calculations, Tilling have complimented 

their SmartFrame floor systems with the certified CONCER- 

TINA FOIL BATTS TM insulation system developed and marketed 

by Wren Industries Pty Ltd. 

TECHNICAL SUPPORT 

Because of the importance that Tilling’s place on the provision 

of expert technical support for their SmartFrame range 

of Engineered Timber Products, designers of sub-floor systems 

are free to contact the SmartData customer helpline 

on 1300 668 690 or at smartdata@tilling.com.au to seek 

advice on how to use the Total R-values R T in this Design 

Guide with energy rating software. 

Designers are also recommended to visit 

www.wpv.org.au/5star and download the excellent PDF 

“Timber - more than a 5 star energy solution” 

For further information specifically related to the CONCERTINA FOIL BATTS, contact Wren Industries Pty Ltd on 

(03) 9532 5855, or email info@concertinafoilbatts.com. 

Website: www.concertinafoilbatts.com LINK - Thermal Performance 


CONCERTINA FOIL BATTS TM - SUB-FLOOR 

QUICK AND EASY TO INSTALL 

EASY TO RETROFIT 

Total R-value of the structure (R T ) is the sum of all component R-values, including the internal airspaces and the surface air films 

on either side of the structure. NB: Framing timbers are excluded from the Total R-value (R T ), as per AS/NZS 4859.1:2002. 

SUB - FLOOR - SmartFrame JOISTS 

ENCLOSED BUILDING PERIMETER 

SFREBP-1 

SUB - FLOOR - SmartJOIST 

ENCLOSED BUILDING PERIMETER 

SFREBP-2 

Brick veneer walls and/or close weave shade cloth behind base boards. 

Brick veneer walls and/or close weave shade cloth behind base boards. 

Perforated CONCERTINA FOIL BATT 

for floors - Over-lapped and stapled 

MIN 90 mm 

depth SmartFrame 

LVL floor joists 




SJ200 & SJ240 

I-Joists 

Non ventilated 

air-space MIN 90 mm 


air-space 90 mm 

Non - 

ventilated 

air-space 

(still air) 

soil 

SmartFrame LVL bearer 

Stumps 

WINTER R T 

R T 3.0* 

SUMMER 

R T 1.5 


air-space 

(still air) 

soil 

Stumps 

WINTER 

R T 3.0* 

SUMMER 

R T 1.5 

Adapted from Wren Industries Pty Ltd.- TF1 from WREN DD-1 

To view WREN DD-1 see www.concertinafoilbatts.com 

LINK Thermal Performance 




SUSPENDED FLOOR - RED ALERT JOISTS 

OPEN BUILDING PERIMETER WITH 

CLOSED JOIST CAVITIES 

SFROBP-1 

SUSPENDED FLOOR - SmartJoist 

- OPEN BUILDING PERIMETER 

WITH CLOSED JOIST CAVITIES 

SFROBP-2 



Non ventilated 50 mm 

Non ventilated 50 mm 

Ventilated sub-floor air-space 

Continuous lining material to create a 

still air joist cavity (with small gaps or 

perforation holes for drainage and breathing) 

Examples - standard RFL roll foil - foil 

side down or fibre cement sheet 

Minimum of 100 mm 

depth SmartFrame 

LVL floor joists 

WINTER 

R T 2.8* 

SUMMER 

R T 1.2 




air-space 100 mm 


air-space 

Ventilated sub-floor air-space 

Continuous lining material to create a 

still air joist cavity (with small gaps or 

perforation holes for drainage and breathing) 

Examples - standard RFL roll foil - foil 

side down or fibre cement sheet 


SJ200 & SJ240 

I-Joists 

WINTER 

R T 2.8 * 

SUMMER 

R T 1.2 







* R T value is dependent upon depth of non-ventilated airspace. For R T values for alternative joist depths, contact Wren Industries Pty Ltd 

Perforated CONCERTINA FOIL 

BATTS TM allow moisture 

drainage and maximum 

breathing of timber flooring, 

and combined with still 

airspaces, produce high and 

consistent thermal 

performance, reflecting 97% 

of radiant heat back to the 

floor. 

FOIL BATTS do not absorb 

or retain heat and therefore 

do not create warm cosy 

nesting environments for 

rodents or pests. 

“BREATHING” AIRSPACES 

ALLOWS GLUEING OF SHEETING 


CONCERTINA FOIL BATTS TM 

INSTALLATION INSTRUCTIONS - FLOORS* 

1) Staple FOIL BATTS 90mm down on sides of floor joists (approx. 6 staples) with a maximum airspace 

depth of 100mm to achieve the maximum R-value for winter. FOIL BATTS are expanded creating a 

shallow concertina profile and held taut with staple in flange corners, to minimise sagging. With 

narrow joist centres gather up excess folds. For 200mm “I” beams, FOIL BATTS are stapled at 100mm 

depth. FOIL BATTS are self supporting. 

2) Overlap adjoining FOIL BATTS by a minimum 50 mm. No cutting is needed. Sealed overlaps are not 

necessary as heat flow is downward radiation in winter, ie. there is no convective winter heat loss from floors 

(refer 7 still air). 

3) FOIL BATTS to be installed as flooring is laid and not be exposed to wind or rain. Open joist ends 

should be covered if necessary for protection from wind and rain during construction, eg dampcourse type 

material. Install FOIL BATTS preferably after electrical, plumbing and ductwork are completed. 

4) Upward FOIL BATT surface is clean, bright and free of all sawdust and debris to obtain best thermal 

performance, i.e. level the tops of joists first before fitting FOIL BATTS, then fit the flooring. 

5) Drainage. FOIL BATTS perforations are specifically designed for platform sheet flooring, where roof is not on. 

Holes are in concertina valleys to allow quick draining of any rain penetrating the floor during construction, as 

well as any moisture formed by possible condensation (low risk generally). 

6) Timbers can breathe because of FOIL BATTS deep airspaces and unsealed overlaps. Be aware that alternative 

insulations will require substantial perforations for drainage and breathing. 

7) Still air. The stated Total R-values are dependent on the creation of still air and zero air velocity beneath timber 

floors for both the airspace above and below FOIL BATTS. 

Enclosed building perimeters achieve this still air with: 

(i) Brick veneer or cavity brick construction – automatically creates still air. Ventilator plates are 

too small to permit high air speed entry and exit. 

(ii) Weatherboard or fibro-cement cladding – minimise gaps between base boards and fix black 

close-weave shade cloth behind boards as a wind break. No air speed. 

Open building perimeters (eg pole frame houses) require a perforated floor joist underlining to create still 

air and ensure breathing and drainage (eg building paper/foil). With 100 mm joists, create two 50 mm 

FOIL BATT airspaces which are surrounded by still air. 

8) Existing Floors. Perforated or non-perforated FOIL BATTS can be used. If there is a risk of 

condensation, then ensure that perforation holes are closest to the ground by reversing the folds of the 

stapling flanges. 

9) Coverage. In winter under floor insulation does not require a 100% complete coverage, eg FOIL BATTS do 

not need to make a tight or close fit around ductwork. 

10) Electrical Safety: Ensure all health and safety precautions are taken when stapling Concertina FOIL BATTS in 

close proximity to electrical cabling. Aluminum foil has the ability to conduct electricity, and incorrect installation 

will provide a safety risk. If in doubt consult a qualified electrician. For further information contact Wren 

Industries. 

(i) New house construction: In new house construction and renovations it is typical that there is no preexisting 

electrical cabling fixed to sides of floor joists, and therefore it is safe to use metal staples for 

fixing fibre batt or foil insulations such as Concertina FOIL BATTS between joists. 

(ii) Retrofit insulation: Where electrical cabling exists and fitted to sides of floor joists, simply position 

Concertina FOIL BATTS above or below cabling to avoid potential conduction. 

For detailed Installation Instructions, refer to www.concertinafoilbatts.com 

* Fixing instructions for FOIL BATTS TM are an extract from the Wren DD1 document. Tilling Timber accepts no responsibility for errors, omissions 

in the fixing details and any responsibility whatsoever in the use of FOIL BATTS in general. 

FOIL BATTS are expanded creating a shallow concertina 

profile and held taut with staple in flange corners, 

to minimise sagging. 

JOISTS 

Staple in flange corner to make FOIL BATTS taut 

50 mm 

Overlap 

STAPLE POSITIONING 

Leaves timber 

free for glue 

STAPLING 

INSTALLED 


DURABILITY AND EXPOSURE TO MOISTURE 

SmartLVL is manufactured from softwood species which 

has a durability rating of class 4, which is the same rating 

as some Ash type Eucalypts. Untreated SmartLVL should 

not be used where the equilibrium moisture content is likely 

to remain above 20% for an extended period. 

Untreated SmartLVL is suitable in the internal, fully protected, 

ventilated and the external above ground, protected 

zones of the structure as shown below. Untreated 

SmartLVL is not suitable for external above ground, exposed 

or humid indoor conditions, such as swimming pool enclosures. 

DEFINITIONS OF EXPOSURE CLASSIFICATIONS 

The table below shows the moisture content of LVL as a 

function of humidity. 

Moisture content of wood products % 1 

Relative Humidity % 

LVL MC 

10 1.2 

20 2.8 

30 4.6 

40 5.8 

50 7.0 

60 8.4 

70 11.1 

80 15.3 

90 19.4 

1. Approx moisture content at 21 0 C 

1. DIMENSIONAL CHANGE 

* External timbers are regarded as protected in AS 1684 if they are covered by a 

roof projection (or similar) at 30° to the vertical and they are well detailed and 

maintained (painted and kept well ventilated). 

MOISTURE EFFECTS ON LVL 

SmartLVL is supplied WITHOUT any short term construction 

sealer, but once framed into a structure may be exposed to 

the weather for a limited time (not greater than 3 months) 

without negative affect, BUT, it may exhibit some effects of 

this exposure. 

SmartLVL, like all wood products, is hygroscopic, which 

means it has an affinity for water. SmartLVL will readily take 

up and release moisture in response to changes in the local 

environment. Moisture exposure will lead to dimensional 

change. While the products will withstand normal exposure, 

excessive exposure during distribution, storage or construction 

may lead to dimensional changes that affect serviceability. 

These changes include cupping, bowing or expansion to 

dimensions to beyond the specified tolerance of the product 

in the “as-manufactured” condition. 

Individual members of a vertically laminated multi member 

may exhibit some cupping if water becomes trapped between 

the laminates. This cupping produces more of a visual 

and possible fixity problem rather than being structurally 

significant. If not properly dried out, this moisture between 

laminated members may lead to decay. To prevent this effect, 

use construction details as shown in full SmartLVL 

Design Guides. 

As an organic material, mold and mildew may grow on untreated 

wood products if moisture is present. Prolonged 

periods of high moisture may also support the growth of 

wood decay fungi, which is another reason to follow proper 

methods of storage and handling of LVL. 

SmartLVL will shrink and swell in proportion to changes in 

their moisture content between 0 and 28 % fibre saturation 

point. The most significant moisture movement will occur 

across the grain (tangential and radial directions within a 

log). Longitudinal (movement in the grain direction) may be a 

factor depending upon the type of structure . Detailing of 

SmartLVL to be used where moisture contents will cycle 

should allow for dimensional instability. 

The amount of dimensional change in a piece of LVL due to 

changes in moisture content can be APPOXIMATED by the 

following formula: 

ΔD = D i S (MC i - MC f )/FSP 

Where: 

ΔD = change in dimension 

D i = Initial dimension 

S = Shrinkage coefficient = approximately 6% 

MC i = Initial moisture content 

MC f = final moisture content 

FSP = fibre saturation point approximately 28% 

E.g. 200 x 42 LVL 15 with MC change from 12-18 % 

- Increase in breadth (thickness) 0.5 mm 

- Increase in depth 2.6 mm 

2. CHANGE IN CHARACTERISTIC STRENGTHS 

Changes in moisture content in wood results in changes in 

mechanical properties, with higher properties at lower moisture 

contents. Estimates of the effect of moisture differentials 

on the properties of clear wood may be obtained by the 

following equation: 

P = P 

12 

 

 

P 

Pg 

12 

Where: 

P= Characteristic property at moisture content 

P 12 = same Characteristic property at 12% moisture content 

P g = same Characteristic property for Green wood 

M p = Intersection moisture content = 24% for Doug Fir 

 

 

 

 

 

 

 

 

 

12−M 

Mp 

−12 

 

 

 

 

 

 


DURABILITY AND EXPOSURE TO MOISTURE (Cont’d) 

The APPROXIMATE affect upon key Characteristic Properties 

of LVL by changes in MC are outlined in the table below: 

Characteristic Property 

Reduction in Characteristic Strength at % MC 

14 16 18 20 22 24 

MOE (Stiffness) E 3.3 6.5 9.7 12.7 15.6 18.4 

MOR (Bending) F'b 8.4 16.1 23.1 29.6 35.5 40.9 

Compression perpendicular 

to grain 

Compression parallel to 

grain 

f'p 9.9 18.9 27.0 34.2 40.8 46.7 

F'c 11.0 20.7 29.4 37.2 44.1 50.2 

Shear f's 6.6 12.8 18.6 24.0 29.0 33.7 

The design Characteristic properties of SmartLVL can therefore 

be considerably reduced by severe increase in MC of 

the LVL. 

If the SmartLVL is being built into structures (such as Prefabricated 

trusses) that are: 

1. Likely to experience large increase in MC due to 

weather exposure or stored on the ground 

2. Likely to be loaded to at/or close to design loads 

while in the high MC state 

then the reduced Characteristic Strengths as detailed above 

NEED to be used in the design or members may require 

temporary propping. 

Once covered, the SmartLVL will ultimately dry and reequilibrate 

to the ambient humidity conditions, but some 

expansion or swelling will remain after re-drying. 

3. DESIGN FOR DURABILITY 

Design & Construction detailing tips 

i. The use of building overhangs and other structures 

which protect the beams from excessive moisture movement 

and sun exposure. 

ii. All beams should be provided with adequate ventilation 

so that moisture content within beams will not exceed 

15% and moisture gradients across the beam will not 

occur. 

iii. The use of arrised or round edges on beams to reduce 

the likelihood of coating failures on sharp edges. 

iv. The use of drip edges or other devices which provide a 

path for free moisture flow away from the timber beam. 

v. Joint detailing should, wherever possible, comply with 

the following: 

· Keep horizontal contact areas to a minimum, in 

favour of self draining vertical surfaces. 

· Ventilate joint surfaces by using spacers, wherever 

possible. 

· Always use compatible fasteners which have 

adequate corrosion protection and do not cause 

splitting during installation e.g. hot dipped galvanic 

coatings or stainless steel. 

· Ensure any moisture entering a joint is not 

trapped but can adequately drain away from the 

joint. 

vi. Allow for thermal expansion/contraction in the joint design. 

HAZARD CLASS SELECTION GUIDE 

HAZARD 

CLASS 

H1 † 

EXPOSURE 

Inside, above ground 

SPECIFIC SERVICE CONDITIONS 

Completely protected from the weather and 

well ventilated, and protected from termites 

BIOLOGICAL 

HAZARD 

Lyctid borers 

TYPICAL USES 

Interior beams, staircases, 

stringers 

H2 

Inside, above ground Protected from wetting. Nil leaching Borers and termites Interior beams, staircases, 

trusses, joists 

H3 

Outside, above ground 

Subject to periodic moderate wetting and 

leaching 

Moderate decay, 

borers and termites 

Exterior beams 

† The timber species in SmartLVL13 are not susceptible to Lyctid Borer attack. 

* Suitable for use South of the Tropic of Capricorn ONLY 

SMARTGUARD ® LOSP TREATMENT 

SmartLVL can be supplied glue-line H2S treated or Smart- 

Guard ® LOSP treated to either H2 or H3 hazard class levels, 

as per AS/NZS 1604.4. To maintain effective treatment 

it is a requirement that any cuts, notches or penetrations 

made in LOSP treated LVL be painted with a suitable 

“brush/spray on” preservative. 

(Note: Water borne treatment processes are NOT suitable 

for SmartFrame EWP). The hazard class number selected 

is based upon the specific exposure condition for the proposed 

end use of the SmartLVL 15, as shown in the table 

above. 

A more comprehensive Hazard Class Table is available in 

AS/NZS1604.4, but it is NOT recommended that 

SmartLVL 15 be used in end uses with exposures requiring 

treatment in excess of H3. 

Experience is showing that LOSP treated timber in the external 

above ground, exposed (H3 Hazard Class) may experience 

some leaching of the active ingredients of the LOSP 

treatment. To minimize the possibility of timber degradation 

in these situations, it is recommended that SmartGuard H3 

treated LVL15 NOT be used where the surface is horizontally 

exposed AND unprotected from water entrapment OR 

where post-treatment protection cannot be maintained. 

Post treatment protection may include: 

(i) Protectadeck TM high density water proof joist/ 

bearer cover or malthoid capping 

and 

(ii) An impervious membrane such as regularly maintained 

painting or staining. 

(iii) Construction detailing to prevent water entrapment. 


SMARTGUARD ® LOSP TREATMENT (Cont’d) 

H3 treated SmartLVL is NOT recommended for fascias, 

pergolas or other similar external above ground, exposed 

applications due to mechanical degradation of the wood 

fibre causing checking and cracking which is both aesthetically 

unacceptable and allows ingress of water to inner veneers. 

FASTENERS FOR SmartGuard H3 LVL 

For SmartGuard H3 LVL to be used in exposed exterior 

applications, it is recommended that either hot dipped galvanised 

or stainless steel fasteners are used. 

PAINTING of SmartGuard ® LOSP TREATED SmartLVL 15 

Wait until excess solvents have evaporated and timber is 

dry. The pressure of the solvent (white spirits) from the 

LOSP treatment may affect the drying and hardening of 

paints if there has been insufficient evaporation time after 

the treatment. It is strongly recommended that the treated 

timber is left to recondition for at least 7 days in the end 

use situation before painting. 

One coat of premium quality primer as a minimum should be 

applied to all surfaces prior to erection of beam and to any 

cuts or holes drilled. If the first coat of primer, sealant paint 

or stain fails to dry or adhere within the time expected, do 

not proceed to any further coats until the first coat has 

achieved satisfactory dryness and adhesion. If the first coat 

fails to dry it may be necessary to strip back to bare timber 

and allow it to weather for another week or two. 

1. Paint 

a. Exterior solid colour acrylic finish. One coat of oil based 

primer followed by one or two coats of the exterior acrylic 

finish as required. 

Or 

b. Exterior solid colour oil based enamel. One coat of oil 

based primer followed by one coat of oil based under-coat 

(if required) then two coats of the oil based enamel. 

2. Stains 

Exterior semi-transparent or solid colour penetrating oil 

based stain or similar. Two or three coats of the stain as 

required or recommended by the manufacturer. 

SMARTGUARD H3 BEARERS AND JOISTS 

SmartGuard H3 treated bearer and joists are a common application for treated SmartLVL. 

H3 treated or naturally durable species decking. 

(LOSP treatment is NOT recommended for 

decking members) 

Protectadeck or malthoid waterproof 

capping to prevent water ponding on 

SmartGuard H3 treated joists and bearers. 

NOTE: It is a requirement that 

any cuts, notches or penetrations 

made in LOSP treated LVL 

be painted with a suitable 

“Brush /spray on” preservative 

SmartGuard H3 treated and painted* LVL 

external deck joists and bearers. 

Recommended proprietary top protection for bearers and joists 

H3 treated or Natural Durability 

class 1 or 2 (sapwood removed) 

decking 

* Painting as per “Painting of SmartGuard LOSP Treated SmartLVL 

15” above 

Protectadeck or 

similar impervious 

membrane to 

prevent water 

ponding on joist 

Recommended Fastening to 

SmartLVL Deck Joists. 

Skew deck 

nails slightly 

to cross 

multiple veneers 

(Galvanised helical 

threaded nails or 

screws) 

H3 treated 

SmartLVL 

joists 


Table of Contents 

RED ALERT 

H2s Treated LVL Bearers & Joists 

PAGES 12 - 13 

• Coloured red for easy identification 

• Sizes 100 x 45, 100 x 63, (100 x 75 - NSW Only) 

• Lengths 3.6 - 9.6m (up to 12.0 m on request) 

• 25 year treatment warranty (conditions apply) 

SmartLVL 15 

Untreated, H2s,H2 and H3 Treated LVL 

Bearers & Joists 

PAGES 14 - 17 

• Treated LVL is clearly marked for easy identification 

• Depths from 90 to 525 mm (Only 90, 130 & 150 reproduced below) 

• Lengths up to 12.0 metres in 300 mm increments 

• 25 year treatment warranty on H2 treated product (conditions apply) 

SmartJoist 

Sub-floor Untreated, H2S and 

H2 Treated Joists 

PAGES 18 - 21 

• Depths from 200 to 400 mm Lengths up to 12.0 metres in 300 mm 

increments 

• 25 year treatment warranty on treated product (conditions apply) 

A graphic 

illustration of just 

one of the key 

advantages of a 

suspended timber 

floor. 

Ask our Design 

Team to design your 

sub-floor to 

accommodate your 

storage needs 

Photo courtesy of 

NEW WATER PTY LTD 

www.newwater.com.au 


RED ALERT 

H2s Treated LVL Bearers & Joists 

• Coloured red for easy identification 

• Sizes 100 x 45, 100 x 63 

• (100 x 75 NSW ONLY) 

• Lengths 3.0 - 9.6 m (up to 12.0 m on request) 

• 25 year treatment warranty (conditions apply) 

• Permatek 1998 Glue-line H2s treatment as per AS/NZS 1604.4. Suitable for use South of the 

Tropic of Capricorn only. Timber Utilisation and Marketing Act 1987 (Section 22) 

• Certificate No 1005. Timber Marketing Act 1977 (NSW) (Section 20) Approval No. 916 74 H2. 

FLOOR JOISTS SUPPORTING FLOOR LOADS ONLY 

Bearer 

Joist span 

Floor Joist 

Spacing 

Example: 

Domestic floor loads 

Single span 

Joist spacing = 450 mm 

Joist span = 1700 mm 

Enter Single Span table at 450 mm in joist 

spacing column, read down to a span equal to 

or greater than 1700 mm 

SmartFrame Red Alert : 100 x 45 

Joist Spacing 300 450 600 300 450 600 

Span O/H Span O/H Span O/H Span O/H Span O/H Span O/H 

Member Size (DxB) mm 

Maximum Single span (mm) 

Maximum Continuous span (mm) 

100 x 45 2100 800 1800 500 1700 600 2700 800 2100 700 1900 600 

It is recommended that floor sheeting or boards be glued to Red Alert with either Fuller Max Bond Pro or Max Bond Fast Grip 


FLOOR BEARERS SUPPORTING JOIST LOADS ONLY 

Bearer supporting 

joist loads only 

Floor joist 

Example: 


Single span = 1600 

Floor load width = 1750 mm 

Enter Single Span table at 1800 mm in floor load 

width column, read down to a span equal to or 

greater than 1600 mm 


Floor 

load 

width 

Bearer span 

Floor Load width mm 1200 1800 2400 3600 4800 

6000 

Span O/H Span O/H Span O/H Span O/H Span O/H Span O/H 

Member Size (DxB) mm 

Maximum Allowable SINGLE span mm 

100 x 63 1800 500 1600 400 1500 450 1200 300 1100 300 1000 300 

100 x 75 * 2000 600 1700 500 1500 400 1300 300 1200 300 1100 300 

Maximum Allowable CONTINUOUS span mm 

100 x63 2300 550 2000 500 1800 4500 1600 400 1400 3500 1200 350 

100 x 75 * 2400 600 2100 500 1900 500 1700 400 1500 400 1300 350 

FLOOR BEARERS SUPPORTING ROOF VIA SINGLE OR UPPER 

STOREY LOADBEARING WALLS - Wind Classification: N1 - N3 

Example: 

Roof load width 

Load 

bearing 

wall 

Bottom plate 

Single or 

Upper storey 

bearer 

Floor joists 

Sheet roof - 40 kg/m 2 

Roof load width = 1450 mm 

Bearer span = 1500 mm 


Enter Single Span table at 1500 mm in floor 

load width column, 1500 roof load width column, 

read down to a span equal to or greater 

than 1500 mm in the 40 kg/m 2 row. 


Bearer span 

Floor load width 

Floor Load width mm 900 1200 1500 

Roof Load width mm 

1500 3000 5000 1500 3000 5000 1500 3000 5000 

Roof 

Mass 

Span O/H Span O/H Span O/H Span O/H Span O/H Span O/H Span O/H Span O/H Span O/H 

Member Size 

(DxB) mm 

kg/m 2 

Maximum Allowable SINGLE span mm 

100 x 63 40 1500 400 1400 400 1300 300 1500 400 1400 400 1200 300 1400 400 1300 300 1200 300 

100 x 75 * 

90 

40 

1400 400 1200 300 1000 300 1300 300 1200 300 1000 300 1300 300 1100 300 1000 300 

1600 400 1500 400 1300 300 1500 400 1400 400 1300 300 1500 400 1400 400 1300 300 

90 1400 400 1200 300 1100 300 1400 400 1200 300 1100 300 1300 300 1200 300 1100 300 

Maximum Allowable CONTINUOUS span mm 

100 x 63 40 2100 600 1900 500 1700 500 2000 600 1900 500 1700 500 1900 500 1800 500 1600 400 

90 1900 500 1600 400 1400 400 1800 500 1600 400 1400 400 1800 500 1600 400 1400 400 

100 x 75 * 40 2200 650 2000 600 1800 500 2100 600 1900 500 1800 500 2000 600 1900 500 1700 500 

90 2000 600 1700 500 1500 400 1900 500 1700 500 1500 400 1800 500 1600 400 1500 400 

* Available in NSW ONLY 


SmartLVL 15 

Untreated, H2s, H2 and H3 Treated LVL Bearers & 

Joists 

• Treated LVL is clearly marked for easy identification 

• Depths from 90 to 525 mm (Only 90, 120, 130, 140 & 150 reproduced below) 


• 25 year treatment warranty on treated product (conditions apply) 

Note: Tables below are an extract from the full SmartLVL 15 Design Guide, available from SmartFrame offices. For sizes 

outside this limited extract or for further information about SmartLVL 15 or SmartFrame products in general, call 1300 

668 690 or by email at smartdata@tilling.com.au. 

FLOOR JOISTS SUPPORTING FLOOR LOADS ONLY 

Bearer 

Joist span 

Floor Joist 

Spacing 

Example: 


Single span 

Joist spacing = 450 mm 

Joist span = 2200 mm 

Enter Single Span table at 450 mm in joist spacing 

column, read down to a span equal to or 


SmartLVL 15 : 130 x 35 

Sizes in Italics are non standard LVL (F17) sizes. Check availability with your SmartFrame stockist before ordering. 

Joist Spacing (mm) 300 450 600 300 450 600 

Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever 

Size DxB (mm) Single Span Continuous Span 

90x35 1800 500 1700 500 1500 450 2300 600 2000 600 1800 500 

130x35 3500 1050 2500 750 2300 600 4000 1100 3000 900 2700 800 

150x35 3900 1150 3000 900 2700 800 4500 1300 3600 1000 3200 950 

90x42 2100 600 1800 500 1700 500 2600 700 2100 600 1900 550 

120x42 3400 1000 2500 750 2300 600 3900 1100 3000 900 2600 700 

130x42 3600 1000 2700 800 2500 750 4200 1200 3300 900 2900 850 

140x42 3800 1100 3000 900 2700 800 4500 1300 3600 1000 3100 900 

150x42 4100 1200 3200 950 2900 850 4700 1400 3900 1150 3400 1000 

90x58 2500 750 2000 600 1900 550 3200 900 2400 700 2200 650 

130x58 3900 1150 3100 900 2800 800 4600 1350 3700 1100 3300 900 

150x58 4400 1300 3600 1000 3300 900 5100 1500 4400 1300 3800 1100 


FLOOR BEARERS 

SUPPORTING JOIST LOADS ONLY 

Bearer supporting 

joist loads only 

Floor joist 

Example: 


Single span = 2100 



width column, read down to a span equal to or 


Floor 

load 

width 

Bearer span 

SmartLVL 15: 130 x 63 


Floor Load Width (mm) 1200 1800 2400 3600 4800 6000 

Maximum Single span sub-floor Bearer span (mm) 

Size DxB (mm) Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever 

2/90x35 1900 500 1600 400 1500 450 1300 300 1100 300 1000 300 

2/130x35 2700 800 2400 700 2100 600 1800 500 1600 400 1500 400 

2/150x35 3200 950 2700 800 2500 750 2100 600 1900 500 1700 500 

90x42 1600 400 1400 400 1200 300 1100 300 NS NS NS NS 

120x42 2100 600 1900 500 1700 500 1400 400 1300 300 1200 300 

130x42 2300 600 2000 600 1800 500 1500 400 1400 400 1300 300 

140x42 2500 750 2200 650 1900 500 1700 500 1500 400 1400 400 

150x42 2700 800 2300 600 2100 600 1800 500 1600 400 1500 400 

2/90x42 2000 600 1700 500 1600 400 1300 300 1200 300 1100 300 

2/120x42 2700 800 2300 600 2100 600 1800 500 1600 400 1500 400 

2/130x42 2900 800 2500 750 2300 600 2000 600 1800 500 1600 400 

2/140x42 3100 900 2700 800 2500 750 2100 600 1900 500 1700 500 

2/150x42 3300 900 2900 800 2600 700 2300 600 2000 600 1900 500 

90x58 1800 500 1500 400 1400 400 1200 300 1100 300 1000 300 

130x58 2600 700 2200 600 2000 600 1700 500 1500 400 1400 400 

150x58 3000 900 2600 700 2300 600 2000 600 1800 500 1600 400 

Floor Load Width (mm) 1200 1800 2400 3600 4800 6000 

Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever 

Size DxB (mm) 

Maximum Continuous span sub-floor Bearer span (mm) 

2/90x35 2400 600 2100 500 1900 450 1600 400 1500 400 1400 350 

2/130x35 3400 850 3000 750 2700 650 2400 600 2200 550 2000 500 

2/150x35 3800 950 3400 850 3200 750 2800 650 2500 600 2300 550 

90x42 2000 500 1700 450 1600 400 1400 350 1200 350 1100 300 

120x42 2700 650 2300 600 2100 550 1800 450 1600 450 1400 400 

130x42 2900 700 2500 600 2300 550 2000 500 1800 450 1600 450 

140x42 3100 750 2700 650 2500 600 2200 550 1900 500 1700 450 

150x42 3300 800 2900 700 2700 650 2300 550 2100 500 1800 5 500 

2/90x42 2500 600 2200 550 2000 500 1700 450 1600 400 1500 400 

2/120x42 3300 800 3000 700 2700 650 2300 600 2100 550 2000 500 

2/130x42 3600 900 3200 750 2900 700 2500 600 2300 550 2100 550 

2/140x42 3800 950 3400 850 3100 750 2700 650 2500 600 2300 550 

2/150x42 4000 1000 3600 900 3300 800 2900 700 2700 650 2500 600 

90x58 2200 550 1900 500 1800 450 1500 400 1400 350 1300 350 

130x58 3200 800 2800 700 2600 650 2200 550 2000 500 1900 450 

150x58 3600 900 3300 800 3000 700 2600 650 2300 600 2200 550 




Example: 


Load 

bearing 

wall 

Bottom plate 

Bearer span 

Single or 

Upper storey 

bearer 

Floor joists 







width column, 1500 roof load width column, read 

down to a span equal to or greater than 1500 mm 

in the 40 kg/m 2 row. 

SmartLVL 15 : 130 x 45 


Floor Load Width 

(mm) 

Roof Load Width 

(mm) 

Roof 

Size DxB Mass 

1200 2400 4800 

1500 4500 7500 1500 4500 7500 1500 4500 7500 

Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever 

(mm) (kg/m 2 ) Maximum Single Span Subfloor Bearer Span (mm) 

2/90x35 40 1700 500 1400 400 1200 300 1500 400 1300 300 1200 300 1200 300 1100 300 1000 300 

90 1500 400 1100 300 1000 300 1300 300 1100 300 1000 300 1100 300 1000 300 NS NS 

2/130x35 40 2400 700 2000 600 1800 500 2100 600 1900 500 1700 500 1800 500 1600 400 1500 400 

90 2200 600 1700 500 1400 400 2000 600 1600 400 1400 400 1700 500 1400 400 1300 300 

2/150x35 40 2800 800 2400 700 2100 600 2500 700 2200 600 2000 600 2000 600 1900 500 1800 500 

90 2500 700 1900 500 1700 500 2300 600 1800 500 1600 400 1900 500 1700 500 1500 400 

90x42 40 1400 400 1200 300 1000 300 1200 300 1100 300 1000 300 1000 300 NS NS NS NS 

90 1200 300 1000 300 NS NS 1100 300 NS NS NS NS NS NS NS NS NS NS 

120x42 40 1900 500 1600 400 1400 400 1700 500 1500 400 1300 300 1400 400 1300 300 1200 300 

90 1700 500 1300 300 1100 300 1500 400 1200 300 1100 300 1300 300 1100 300 1000 300 

130x42 40 2100 600 1700 500 1500 400 1800 500 1600 400 1400 400 1500 400 1400 400 1300 300 

90 1800 500 1400 400 1200 300 1600 400 1300 300 1200 300 1400 400 1200 300 1100 300 

140x42 40 2200 600 1800 500 1600 400 1900 500 1700 500 1500 400 1600 400 1500 400 1400 400 

90 2000 600 1500 400 1300 300 1800 500 1400 400 1300 300 1500 400 1300 300 1200 300 

150x42 40 2400 700 2000 600 1800 500 2100 600 1800 500 1700 500 1700 500 1600 400 1500 400 

90 2100 600 1600 400 1400 400 1900 500 1500 400 1400 400 1600 400 1400 400 1300 300 

2/90x42 40 1800 500 1500 400 1300 300 1600 400 1400 400 1200 300 1300 300 1200 300 1100 300 

90 1600 400 1200 300 1100 300 1400 400 1200 300 1000 300 1200 300 1000 300 NS NS 

2/120x42 40 2400 700 2000 600 1800 500 2100 600 1800 500 1700 500 1700 500 1600 400 1500 400 

90 2100 600 1600 400 1400 400 1900 500 1600 400 1400 400 1600 400 1400 400 1300 300 

2/130x42 40 2600 700 2200 600 1900 500 2300 600 2000 600 1800 500 1900 500 1700 500 1600 400 

90 2300 600 1800 500 1500 400 2100 600 1700 500 1500 400 1800 500 1500 400 1400 400 

2/140x42 40 2800 800 2300 600 2100 600 2500 700 2100 600 2000 600 2000 600 1900 500 1700 500 

90 2500 700 1900 500 1700 500 2200 600 1800 500 1600 400 1900 500 1700 500 1500 400 

2/150x42 40 3000 900 2500 700 2200 600 2600 700 2300 600 2100 600 2200 600 2000 600 1900 500 

90 2600 700 2100 600 1800 500 2400 700 2000 600 1700 500 2100 600 1800 500 1600 400 

90x58 40 1600 400 1300 300 1200 300 1400 400 1200 300 1100 300 1100 300 1000 300 1000 300 

90 1400 400 1100 300 NS NS 1300 300 1000 300 NS NS 1100 300 NS NS NS NS 

130x58 40 2300 600 1900 500 1700 500 2000 600 1800 500 1600 400 1700 500 1500 400 1400 400 

90 2000 600 1600 400 1400 400 1800 500 1500 400 1300 300 1600 400 1400 400 1200 300 

150x58 40 2700 800 2200 600 2000 600 2300 600 2000 600 1800 500 1900 500 1800 500 1600 400 

NOTES 

90 2300 600 1800 500 1600 400 2100 600 1700 500 1500 400 1800 500 1600 400 1400 400 

ROOF LOAD WIDTH: 

For definition of roof load width, see AS 1684.2. 

1. The above table was based on a maximum DL of 40 (kg/m 2 ), Total Wall Mass of 15 (kg/m 2 ), Floor Live Load of 1.5 (KPa), Floor Point Load 

of 1.8 (KN), 

2. Minimum Back span = 200% of Overhang. Maximum Overhang = 30% of Back span. 

BEARING LENGTHS: 

End bearing lengths = 42 mm at end supports and 58 mm at internal supports for continuous members. Subscript values indicate the minimum 

additional bearing length where required to be greater than 42 mm at end supports and 58 mm at internal supports. 





Load 

bearing 

wall 

Bottom plate 

Bearer span 

Single or 

Upper storey 

bearer 

Floor joists 


Example: 






width column, 1500 roof load width column, read 

down to a span equal to or greater than 1500 mm 

in the 40 kg/m 2 row. 

SmartLVL 15 : 130 x 45 


Floor Load Width (mm) 1200 2400 4800 

Roof Load Width (mm) 1500 4500 7500 1500 4500 7500 1500 4500 7500 

Roof 

Size DxB 

Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever Span C'lever 

Mass 

(mm) (kg/m 2 ) Maximum Continuous Span Subfloor Bearer Span (mm) 

2/90x35 40 2300 600 1900 500 1700 500 1900 500 1800 500 1600 400 1500 400 1500 400 1400 400 

90 2000 600 1600 400 1400 400 1800 500 1500 400 1300 300 1500 400 1400 400 1200 300 

2/130x35 40 3300 850 2800 800 2500 700 2700 800 2600 700 2300 600 2200 600 2200 600 2100 600 

90 2900 850 2300 600 2000 600 2700 800 2200 600 1900 500 2200 600 2000 600 1800 500 

2/150x35 40 3800 1000 3200 900 2900 800 3200 950 3000 900 2700 800 2500 700 2500 700 2400 700 

90 3400 1000 2600 700 2300 600 3100 900 2500 700 2200 600 2500 700 2300 600 2100 600 

90x42 40 1900 550 1600 400 1400 400 1600 400 1500 400 1300 300 1200 300 1200 300 1100 300 

90 1700 500 1300 300 1100 300 1500 400 1300 300 1100 300 1200 300 1100 300 1000 300 

120x42 40 2600 700 2200 600 1900 500 2100 600 2000 600 1800 500 1700 500 1600 400 1500 400 

90 2300 600 1800 500 1500 400 2100 600 1700 500 1500 400 1700 500 1500 400 1400 400 

130x42 40 2800 750 2300 600 2100 600 2300 600 2200 600 2000 600 1800 500 1800 500 1700 500 

90 2500 750 1900 500 1700 500 2300 600 1800 500 1600 400 1800 500 1600 400 1500 400 

140x42 40 3000 800 2500 700 2200 600 2500 750 2300 600 2100 600 2000 600 1900 500 1800 500 

90 2700 800 2100 600 1800 500 2400 700 2000 600 1700 500 1900 500 1700 500 16005 4005 

150x42 40 3300 850 2700 800 2400 700 2700 800 2500 700 2300 600 2100 600 2000 600 1900 5 500 

90 2900 850 2200 600 1900 500 2600 700 2100 600 1900 5 500 2100 600 1900 5 500 1700 15 500 15 

2/90x42 40 2400 650 2000 600 1800 500 2000 600 1900 500 1700 500 1600 400 1600 400 1500 400 

90 2200 650 1700 500 1400 400 2000 600 1600 400 1400 400 1600 400 1400 400 1300 300 

2/120x42 40 3300 850 2700 800 2400 700 2700 800 2500 700 2300 600 2100 600 2100 600 2000 600 

90 2900 850 2200 600 1900 500 2600 700 2100 600 1900 500 2100 600 1900 500 1800 500 

2/130x42 40 3500 900 3000 900 2600 700 2900 800 2700 800 2500 700 2300 600 2300 600 2200 600 

90 3100 900 2400 700 2100 600 2800 800 2300 600 2000 600 2300 600 2100 600 1900 500 

2/140x42 40 3700 1000 3200 900 2800 800 3100 900 2900 800 2700 800 2500 700 2500 700 2400 700 

90 3400 1000 2600 700 2300 600 3100 900 2500 700 2200 600 2500 700 2300 600 2100 600 

2/150x42 40 3900 1050 3400 1000 3000 900 3300 900 3100 900 2900 800 2700 800 2700 800 2600 700 

90 3600 1050 2800 800 2400 700 3300 900 2700 800 2400 700 2700 800 2400 700 2200 600 

90x58 40 2200 600 1800 500 1600 400 1800 500 1700 500 1500 400 1400 400 1400 400 1300 300 

90 1900 500 1500 400 1300 300 1700 500 1400 400 1200 300 1400 400 1300 300 1100 300 

130x58 40 3100 800 2600 700 2300 600 2600 700 2400 700 2200 600 2000 600 2000 600 1900 500 

90 2800 800 2100 600 1900 500 2500 700 2000 600 1800 500 2000 600 1900 500 1700 500 

150x58 40 3600 950 3000 900 2700 800 3000 900 2800 800 2500 700 2300 600 2300 600 2300 600 

NOTES 

90 3200 950 2500 700 2200 600 2900 800 2400 700 2100 600 2300 600 2100 600 1900 500 

ROOF LOAD WIDTH: 

For definition of roof load width, see AS 1684.2. 

1. The above table was based on a maximum DL of 40 (kg/m 2 ), Total Wall Mass of 15 (kg/m 2 ), Floor Live Load of 1.5 (KPa), Floor Point Load 

of 1.8 (KN), 

2. Minimum Back span = 200% of Overhang. Maximum Overhang = 30% of Back span. 

BEARING LENGTHS: 

End bearing lengths = 42 mm at end supports and 58 mm at internal supports for continuous members. Subscript values indicate the minimum 

additional bearing length where required to be greater than 42 mm at end supports and 58 mm at internal supports. 


SmartJoist sub-floors 

Untreated,H2s and H2 treated 

• Depths from 200 to 400 mm (Only 200 and 240 reproduced below) 


• 25 year treatment warranty on H2 treated product (conditions apply). 

Note: Tables below are an extract from the full SmartJoist Design Guide, available from Tilling Timber 

offices. For sizes outside this limited extract or for further information about SmartJoists or Smart- 

Frame products in general, call 1300 668 690 or by email at smartdata@tilling.com.au. 

TYPICAL LAYOUTS 

SmartJoist Joists 

(Joist hangers omitted for clarity) 


bearer 

Detail 1 

In-line bearer and joist 

In-line bearer and joists can 

assist where ground clearance 

is at a minimum or 

allows average overall depth 

of the floor to be minimised 

but maintaining the long 

span capability of the joists 

Joist 

hanger 

SmartJoist floor 

joists 

SmartLVL 

Bearer 

CROSS SECTION 

Shows alternative stump/pier types, 

and both in-line and stacked joist systems 

SmartJoist 


Bearer 

Detail 2 

Stacked bearer and joist 

Stacked bearer and joist 

allows continuous span joists 

to be used (supported at 3 or 

more supports). Continuous 

spans may reduce the joist 

depth in some circumstances. 

SmartLVL 

bearer 

Steel 

pier 

SmartJoist 

H4 treated 

round timber 

stump 

SmartLVL 

bearer 

Concrete 

stump 


THE SmartJoist SUBFLOOR ALTERNATIVE 

(Reduced stump/pier numbers and ground disturbance) 

External bearer supports 

at 2400 mm Max centres 

Internal bearer supports 

2400mm MAX 

Bearer direction 

Joist span 

2400mm MAX 

Joist direction 

EXAMPLE STUMP/PIER LAYOUT FOR A 

TRADITIONAL 2400mm GRID 

Bearer span 

Joist span 

No of 

stumps/pier Supports * 

Total bearer Length * 

Lin m Lin m No Lin m 

1.8 1.8 114 179 

2.4 2.4 71 145 

3.0 4.5 44 90 

* May depend upon external cladding. 

Based upon a floor area of 270m² 

CONVENTIONAL 

SUB-FLOOR SYSTEM 

SMARTJOIST SUB-FLOOR SYSTEM 

External bearer supports 

at 2700 mm Max centres 

Bearer direction 

Internal bearer supports 

3000 mm MAX centres 

Joist span 

4500 mm MAX 

Joist direction 

EXAMPLE STUMP/PIER LAYOUT FOR A SmartJoist 

SUB FLOOR GRID 


TYPICAL SmartJoist FLOOR CONSTRUCTION DETAILS 

SmartJoist 

blocking 

panel 

SmartJoist 

rim joist 

Butt sections together 

at centre of lower 

storey stud. 

SmartRim 

Rimboard 

(2 layers for 

ground floor 

of a 2 storey 

building) 

F1 

F2 

Load-bearing wall 

F3 

F4 

Joists 

Bearer 

SmartRim 

Rimboard 

Small section of bearer material placed 

on stumps/piers to support joists 

supporting parallel load-bearing walls. 

F5 

CONCENTRATED 

ROOF LOADS 

Solid block all posts 

from above to 

bearing below. 

SmartJoist shall be designed 

to support load bearing wall 

above when not stacked over 

wall below. 

Backer for cladding 

attachment. 

SmartJoist 

blocking 

panel 

F6 

Used double 

joists under 

wall where 

vertical load 

exceeds 

29 KN/m 

Note: 

To achieve the necessary 

racking resistance through the 

floor diaphram, it is important 

that the nailing provisions of the 

floor sheeting to the joists as shown 

in AS 1684 (and AS 1860 for 

particleboard) be adopted to nail the 

floor sheeting to the SmartRim 

Rimboard in details F1- F3 

Load bearing wall 

above must stack 

over wall below 

2 mm 

F7 

NOTE: Detail F7 with blocking panel is required for bracing walls. 

F8 

90 X 45 F5 

Cripple skew 

nailed to both 

flanges with 

3.15 x 65 nails. 

GREEN TIMBER SHALL NOT BE USED AS END BLOCKING UNDER 

ANY CIRCUMSTANCES. IT IS STRONGLY RECOMMENDED THAT 

ALL BLOCKING BE CARRIED OUT AS PER DETAILS F1 - F4, 

HOWEVER: Dry timber blocking may be used but the grain MUST 

be vertical. BLOCKING OF SmartJoist MUST EXTEND TO BOTH 

FLANGES. Skew nail with 3.15 x 65 nails, one each side of 

top and bottom flange. 


RECOMMENDED MAXIMUM SPANS FOR RESIDENTIAL FLOORS 

GENERAL DOMESTIC - 1.5 kPa 

Loadings: Permanent Loading G: Self Weight + 40 kg/m 2 + O.6 kPa of Live Load permanently applied, 

Live Load Q: 1.5 kPa or 1.8 kN point Live Load 

Joist Spacing (mm) 

300 400 450 600 300 400 450 600 

SmartJoist Self Weight Maximum floor Joist span (mm) 

Code (kg/m) Single Span Continuous Span 

SJ20044 2.8 4700 4300 4100 3700 5500 5100 4900 4400 

SJ24040 3.0 5100 4700 4600 4200 6000 5500 5400 4900 

SJ24051 3.4 5400 5000 4900 4500 6300 5800 5700 5200 

SJ24070 4.0 5900 5400 5200 4900 6600 6100 6000 5500 

SJ24090 5.0 6200 5700 5600 5100 7200 6700 6500 6000 

SJ30040 3.4 5900 5400 5300 4900 6800 6300 6100 5700 

SJ30051 3.9 6200 5700 5600 5100 7200 6700 6500 6000 

SJ30070 4.3 6700 6100 6000 5500 7600 7100 6800 6300 

SJ30090 5.5 7000 6500 6300 5900 8200 7600 7400 6800 

SJ36058 4.8 7200 6600 6500 6000 8300 7700 7500 6900 

SJ36090 5.9 7800 7200 7000 6500 9100 8400 8200 7600 

SJ40090 6.2 8300 7700 7500 6900 10000 9000 8700 8000 

In compiling the span tables in this manual, the requirements of the relevant Australian Standards and codes along with established 

Industry standard design guidelines for Residential Construction have been followed. In particular, the following codes and 

references have been used: 

• AS 1684.1 Residential timber-framed construction 

• AS 1170.1 Structural Design Actions – Permanent Imposed and other actions 

• AS 1720.1 Timber Structures - Design Methods 

• AS 4055 Wind loads for Houses 

• ASTM D 5055 Standard specification for establishing and monitoring structural capacities of prefabricated wood I- 

Joists 

SERVICEABILITY CRITERIA: 

Max dead load deflection - lesser of span / 300 or 15 mm (j 2 = 2) 

Max live load deflection - lesser of span / 360 or 9 mm 

FLOOR DYNAMIC PERFORMANCE CRITERIA: 

Minimum Natural Frequency - 8 Hertz 

Maximum differential deflection between Joists of 2 mm under a concentrated load of 1.0 kN mid-span. 

FLOORING: 

Spans are suitable for solid timber, particle board and ply flooring. Floor sheathing glued and nailed to the joists will improve 

floor rigidity. Where a heavy overlay material is to be applied, such as thick mortar bed tiled or slate floors, the permanent load 

allowance should be increased to 1.2 kPa. A reduction of joist spacing can be used to accommodate this extra permanent 

load. A satisfactory result can be achieved by adopting the maximum spans for 600-mm and 450-mm spacings but installing 

the joists at 450-mm and 300-mm spacings respectively. 

CONTINUOUS SPANS: 

For beams which are continuous over two unequal spans, the design span and the "resultant span description" depend on the 

percentage difference between the two spans as shown below: 

Span difference 

Effective span 

Resultant span description 

10% max main span continuous 

10 - 30% 1.1 x main span continuous 

above 30% diff main span Single 

Span difference = (main span - second span) 

(main span + second span) X 100 

Main span 

Second span 


SmartFrame TOOLS 

SmartFrame Software 

You really do need to see our software to believe it. This 

state of the art FREE software is world leading technology. 

Not only does it provide the services noted previously, but 

you also have the benefit of being able to ‘size’ specific 

members for your project—fast. No other software package 

can give you all these benefits at no charge. 

Quick Design - 

Can’t get a particular timber? Just enter the spans and 

you have a SmartFrame alternative. It’s that easy. 

Take-Off - 

This is the module from which we produce our designs. 

Either use this yourself, or send the plans to us and we’ll 

do it for you. The take-off is provided in A3 full colour easy 

to read layouts. 

Bracing - 

More for Designers and Engineers, this module will work 

out force summaries for wind bracing and more. 

Connection Details - 

Ever wondered how to connect an I-Joist to a steel PFC? 

If you have, this is the module for you. Over 30 different 

types of connection details all with easy to read graphics 

and detailed notes. 

Select Bracket - 

Want to be sure you’ve got the hardware? Visit ‘select 

bracket’ and you’ll get all the info you need i.e.: size, the 

joists it suits and order code. Choose from straight face 

mount hangers, top mounts, 45° offsets, rafter to ridge 

hangers and even heavy duty hangers for our LVL. 

Tie Down - 

A powerful tool to enable users to quickly calculate the 

uplift forces on a structure and to assign suitable tie down 

solutions as contained in Chapter 9 of AS 1684 

Reports - 

Need a certificate report for council? Easy—just switch on 

your PC, bring up the job and hit the reports button. In one 

or two minutes, you’ll have complete computer generated 

certifications suitable for most councils and inspectors. Of 

course, if they aren’t satisfied, send the job to us and our 

Engineer will check it, ensure it’s correct and then issue 

you an Engineer’s Certificate. 

SmartFrame Design Service 

Tilling offer a comprehensive design service to builders as 

part of our SmartFrame builders program—at no charge. 

Simply give us your plans and we’ll supply you with the following: 

1.Floor Beam/Post/Lintel Layout - This clearly show 

where members go, what they 

bear onto and how they connect 

within the frame, all in easy to 

read colour graphics. 

2. Joist Layout - Showing the 

layout of joists, bearing points, 

where to start your layout and 

other site specific details such 

as joist hangers and rimboard/ 

end blocking. These layouts can include location of service 

holes so the tradesman can adjust the joists as necessary. 

3. Member Schedule - Our member schedule illustrates 

the direction of each member, size, length, count, how it 

bears left and right and any other information deemed to 

be needed. 

4. Order Schedule - This is the take off to build the floor. 

Simply take a look at it to check everything is included, 

then fax it to your merchant for supply. 

Training 

Installation Training - It’s not always easy for carpenters to 

keep up to date on new products, however to produce a 

well built, strong home, it’s a necessity. At Tilling, we realize 

that education and training are lynch pins of the Smart- 

Frame range. If you’ve ever used our products before, or 

you’ve just started a new chippie crew, give us a call. Given 

either on site, in your office or ours, installation training 

runs through all the details required to install our joists 

and LVL, including shortcuts to save time and money. 

Once again this service is provided at no charge to Smart- 

Frame users. It’s all part of the service to ensure you can 

work with confidence. WORK SMARTER - NOT LONGER 

WITH SmartFrame. 

Software Training - Want to become a 

SmartFrame expert yourself—give us a call. 

We have a National Training Coordinator 

who can arrange training from beginners to 

the most advanced user either at your work 

or at one of the Tilling State offices. 

Tillings are now a Registered Training Organization for the 

Victorian Building Commission and thus SmartFrame training 

now earns valuable CPD points 


For more information call 1300 668 690 or visit www.tilling.com.au 

31-45 Orchard Street, Kilsyth 

Victoria 3137, Australia 

Email: smartdata@tilling.com.au 

Telephone +61 3 9725 0222 

Facsimilie 1300 668 650 

illing 

© 2010 Tilling Timber Pty Ltd ABN 92 004 621 121 Date of publication September 2010 Smartframe is a Registered Trademark of Tilling Timber

SmartFrame Subfloor Design Guide - Tilling Timber

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