SmartFrame Subfloor Design Guide - Tilling Timber

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.
SmartFrame Sub-floor Design Guide 4