Knauf Free-Spanning Ceiling D131

Knauf Free-Spanning Ceiling
Construction and application, jointing, surface treatment
D131
Construction
Knauf Free-Spanning Ceilings are solely fastened
to the walls at perimeter. Knauf Boards
GKB/ GKBI impregnated, Fire-Resistant Boards
GKF/ GKFI or LaVita Shielding Boards are
screwed to a metal grid made of Knauf CW profi
les as single or double profi les.
The application of additional loads like lighting fi x-
tures with max. 100 N (10 kg) per double profi le
and exposed ceilings like e.g. D127 Knauf Apertura
Acoustical Ceiling with load per unit area of
Application
Metal Grid
● Perimeter connection to walls with UW runners.
Fastening according to table page 3 at
centers of ≤ 625 mm.
● For sound protection requirements seal up
carefully with acoustical sealant according to
DIN 4109, supplement 1, chapter 5.2; porous
sealant strips like Sealing Tape are usually not
suitable in this case.
● CW profi les as double profi les are screwed at
web with metal screws LB 3.5 x 9.5 mm at
max. 750 mm centers.
● Support of CW profi les in UW runners ≥ 30
mm. Crimp, screw or rivet upper fl anges of
CW profi les and UW runners to each other if
no covering strip is necessary.
Jointing / Surface Treatment
Jointing
For higher optical quality requirements like occuring
streak of light, Knauf boards with 4-AK
edges are the ideal basis for a perfect jointing
with joint tape, Knauf Fugenfüller Leicht or Readygips.
With 4-AK Boards the usual displacement
of cut edges of at least 400 mm can be replaced
by the much more effective cross joint
application and jointing.
Filling Material
Fill joints with Knauf Uniflott without using tape.
If using tape, hand fill with Knauf Fugenfüller
Leicht or with Ames Machine and Knauf Jointfiller-Super.
Knauf Unifl ott impregnated is additionally water-repellent
and fi ts to the color of impregnated
Knauf Boards. Use Knauf Finish-Pastös for the
fi nal fi lling coat as fi ne skimming before sanding
the joints.
Application
For double layer cladding, fill joints of first layer,
smooth joints of second layer. Cover all screw
heads as well.
Recommendation: Fill and tape cut edges of
visible layers no matter which filling material is
used.
Knauf Spezialgrund as primer for skimming of
entire ceiling surface to regulate the behavior of
soaking and to improve the optical conformity is
15 kg/m² resp. max. single load of 100 N with
suitable anchors directly to the metal grid is permissible.
Joints of free-spanning channels are
not allowed! Settlement joints have to be taken
over into the construction of the free-spanning
ceilings. Use control joints in the case of ceiling
areas over approx. 15 m length, or for narrow
ceiling spaces caused by a break of a wall.
Separate connections of boards to components
made of a different building material,
Cladding
● Screw Knauf Board Strips GKF, 25 mm thick,
as covering strips on upper fl anges of CW
profi les with Drywall Screws TN 3.5 x 35 mm
at max. 250 mm centers, on CW double profi
les alternating.
● Apply Knauf Boards lateral to CW profi les.
● Displace cut edge joints at least 400 mm while
placing them on profi les. If using 4AK Boards
(4-side taperd egdes) cross joints are allowed
in connection with fi lling with joint tape.
● Start fastening of Knauf boards either in the
middle or at a corner in order to prevent upsetting
deformation. Press boards fi rmly on to
the grid and screw with Drywall Screws TN at
170 mm centers alternating to CW profi les.
a system component to create of surfaces with
higher quality standards according to data sheet
no. 2 „Verspachtelung von Gipsplatten - Oberfl
ächengüten“ of the IGG.
Application temperature/ climate
Filling and covering of joints should only take
place after the boards have been allowed to rest
in the given humidity and temperature zones,
and no more longitudinal changes can be expected,
i.e. expansion or contraction. Joints
should be filled at a minimum temperature of
10°C. In case of mastic asphalt screed, fill in
joints after screed has been applied.
Surface Treatment
Use a primer on Knauf Boards before coating or
painting them. Ensure that the primer and the
coat or paint are compatible.
After wallpapering of paper and fi ber glass wallpapers
and the application of resin / cellulose
plasters quick drying must be assured through
adequate airing. The following coats can be
used to cover Knauf Boards:
● Wall Papers: paper-, textile and synthetic wall
papers. Use only adhesives made of cellulose
according to „Merkblatt Nr. 16, Technische
Richtlinien für Tapezier- und Klebearbeiten“,
Frankfurt/Main 2002, released by Bundesausschuss
Farbe und Sachwertschutz.
especially columns, or thermical highly stressed
built-ins like lighting fi xtures, for instance with
control joints.
Knauf profi les are delivered galvanized. The corrosion
protective coating is suffi cient for indoor
application, including bathrooms and kitchens in
private housing. For other areas, e.g. under infl
uence of outdoor air, additional corrosion protection
is necessary (see DIN 18168-1 table 2).
● Screwing of boards, 12.5 mm thick, with Drywall
Screws TN 3.5 x 25 mm; 18 or 25 mm →
TN 3.5 x 35 mm; 2 x 12.5 mm → TN 3.5 x 25
mm + TN 3.5 x 35 mm.
● With double layer cladding centers of screws
of fi rst layer can be extended to max. 500 mm
if the second layer is applied subsequently
(within one working day).
● Use separation strip Trenn-Fix 65 and fi ller
or acrylate for connections to other components.
Ceiling below ceiling
Application according to instructions on page 7.
● Plasters: Knauf structured plasters, e.g. re sin
plasters, thin plasters, entire area smoothing
like e.g. Knauf Board-Finish, mineral plasters
in connection with paper taped jointing.
● Coats: Washable and abrasion-proof emulsion
paint, multicolored (rainbow) emulsion,
oil paint, matte-fi nish lacquer, alkyd resin
paint, polymer resin paint, PUR lacquer, or epoxybased
lacquer, according to intended use
or as required.
● Alkaline coats such as lime, water glass colors
and silicate-based paints are unsuitable
for gypsum board surfaces. Silicate-based
emulsion paints may be used after referring to
the manufacturer’s recommendations and following
the stipulated guidelines closely.
Gypsum board surfaces that have constantly
been exposed to light without any protection can
develop yellowing agents that show up despite
a coat of paint. Therefore a trial coat is recommended
that will extend across several boards
including all joints. Yellowing can, however, be
successfully avoided only by using a special
shielding primer.
Knauf Direkt Technical Information Service: Phone +49 18 05 / 31-10 00, Fax +49 18 05 / 31-40 00
Knauf websites: www.knauf.de, www.knauf.com e-Mail: knauf-direkt@knauf.de
Knauf Headquarters, Am Bahnhof 7, D-97346 Iphofen, Phone +49 93 23 / 31-0, Facsimile +49 93 23 / 31-277
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© All technical changes reserved. Only the current printed instructions are valid. Our warranty is expressly limited to our products in flawless condition. All application quantities and delivery amounts are based on empirical data that is not easily transferable to
other deviating areas. All rights reserved. All amendments, reprints and photocopies, including those of excerpts, require the express permission of Knauf Gips KG, Am Bahnhof 7, 97346 Iphofen, Germany.
Edition: June 2005
D131 / engl. / D / 06.05 / FB / D