Weather Defence
Installation instructions
Siniat B.V. ● Oosterhorn 32-34 ● 9936 HD FARMSUM
Technical Service Desk +31 (0) 596 – 649 333
www.siniat.nl
July 2014
1. Introduction
Siniat's Weather Defence gypsum plasterboard 9.5mm is specially developed for external wind protection
during the construction process.
2. SINIAT Weather Defence
The Siniat Weather Defence system is suitable both for metal and wooden constructions. This system
gives the building a robust exterior façade cladding. The boards can be left exposed to direct weather
and wind for up to 12 months during on-going construction work.
2.1 Siniat's vertical studs for infill walls
For non-load bearing infill walls, Siniat's C-metal studs 1.2 mm gauge, or SFS (Structural Framing
Systems) C-studs can be used, after approval from a structural engineer with the appropriate authority.
The maximum height permitted for Siniat infill walls is calculated in accordance with Eurocode 3,
(EN 1993-1-3 and its national annexes), for wind load resistance, both for durability and maximum load.
Fix the U-profiles along the construction line, at the floor and ceiling with suitable fasteners from the
manufacturer with a centre distance of maximum 600 mm. If the U-profiles are fixed directly on newly
cast concrete that has not dried completely, then a moisture barrier must be used. Cut Siniat C-studs 5
mm shorter than the distance between the floor and the ceiling in order to provide space for varying
floor heights. Insert the C-studs in the U-profiles and turn them into position.
The outer C-studs must be fixed closely against the supporting wall or beam with suitable fastener from
the manufacturer, with a centre distance of maximum 600 mm. All intermediate C-studs must be turned
in the same direction and be placed with a centre distance of maximum 600 mm (or a reduced centre
distance of 450 mm between the studs if so required from a working environment point of view).
To make the system as air and rain tight as possible and to give the system maximum acoustic and fire
technical performance, a swelling acoustic sealant is to be used between the construction's outer edge
and the Siniat Weather Defence board. A self-adhesive foam tape in one piece on the back side of the
U-profiles and the outer C-studs can also be used.
2.2 Vertical studs of wood
Siniat Weather Defence gypsum plasterboards can be installed directly on the outside of a wood frame.
The wooden framework must be constructed in accordance with Eurocode 5 (EN 1995-1-2 and its
national annexes) in order to resist both vertical load and wind resistance.
2.3 Secondary framework
A secondary framework can be used for exterior ventilated or drained cavities. The framework may be
made of steel studs or wood studs. Metal furring channels or wooden battens are fixed horizontally or
vertically to the framework.
Siniat B.V. ● Oosterhorn 32-34 ● 9936 HD FARMSUM, THE NETHERLANDS
Technical Service +31 (0) 596 – 649
333 www.siniat.se
Page 1 of 3
2.4 Installation of Siniat Weather Defence
Siniat Weather Defence gypsum plasterboards may only be fixed to a metal or wooden framework with
vertical studs placed with a centre distance of maximum 600 mm.
Studs and screws must be CE marked and approved for the area of use. Self-drilling or self-threading
screws with bevelled edges are used. They must have a length of minimum 32 mm for mounting on steel
studs and minimum 42 mm for mounting on wooden studs. The screws must be intended for mounting
gypsum plasterboards and have a corrosion class of C4 or higher.
Weather Defence boards should preferably be installed vertically. If the boards are installed horizontally,
the joints shall be supported half way by horizontal studs, noggins or metal strips. If horizontal noggins
are used in the frame as a support for horizontal joints, the Weather Defence boards must be screwed to
the noggins.
Weather Defence gypsum plasterboards can be cut using a suitable knife to first cut the surface of the
board, break it and then cut off the remaining part, in order to finally adjust the board in place with a
jigsaw.
Fix the Siniat Weather Defence board to the steel frame with self-drilling or self-threading screws, at
least 32 mm long with a centre distance of maximum 300 mm. Stagger the joints on the outer board
layer by a minimum of 600 mm compared with the inner layer if double layers are used.
Fix the Siniat Weather Defence board to the wooden frame with Siniat WAB self-drilling or self-threading
screws, at least 42 mm long with a centre distance of maximum 300 mm. Stagger the joints on the outer
board layer by a minimum of 600 mm compared with the inner layer if double layers are used.
For prefabricating when the wall is assembled in factory, the screws can be replaced with staples or nails
with a centre distance of maximum 200 mm.
Seal the joints between the Weather Defence boards by applying a tape to ensure optimal air and water
tightness. The minimum width on the tape strip must be 50 mm. The tape must be of a type that is
intended for this purpose. Examples of tapes are PAROC XST 013 or PAROC XST 020.
The taping must be checked so that damage or other defects do not occur during the time the boards
are exposed to weather and wind. If needed, the tape is to be repaired, supplemented or replaced.
If additional sealing is deemed as being necessary, first apply a string of silicone on the edge of the
board, on the one side of the joint, just before the other board is mounted.
When the Weather Defence board is fixed with screws, accuracy must be observed so that no screws
protrude on the surface of the board or have been screwed in too deep. Screws must have a minimum
distance of 15 mm from the joint.
Siniat B.V. ● Oosterhorn 32-34 ● 9936 HD FARMSUM, THE NETHERLANDS
Technical Service +31 (0) 596 – 649
333 www.siniat.se
Page 2 of 3
3. Wind load
The Weather Defence board is intended for use as a wind protection board in exterior walls. The
Weather Defence board is screwed firmly into load bearing wooden or metal studs and can be left
exposed to weather and wind during the construction phase of the building. The Weather Defence board
can handle mechanical stress in the form of wind loads and in combination with high humidity and rain.
The resistance of the Weather Defence board against wind loads is shown in the table below. The value
of wind loads shown in the table is based on tests of the Weather Defence board on full sized walls and
based on calculations in accordance with Eurocode EN 1990 and from The Swedish National Board of
Housing, Building and Planning's EKS, Eurocodes and national annexes. These calculations are based on
several safety factors such as partial coefficient for material properties, partial coefficient for safety class
and partial coefficient for load and for model and dimension instability.
In the values, regard has not been paid to other factors such as form factor and the building's height
which is relevant for the construction of the building (must be calculated by the responsible builder).
The resistance against wind loads depends on the distance between the studs and the distance between
screws.
Table 1: Characteristic load capacity in safety class 1
Distance
between studs
Distance
between screws
Capacity
(mm)
(mm)
Qk-value (kPa) based on pull-through
resistance of screws
600
600
450
450
300
200
300
200
0.85
1.28
1.14
1.70
400
400
300
200
1.28
1.92
Higher resistance against wind loads can be obtained by installing horizontal battens between the
vertical studs.
Shorter centre distances can be required in order to achieve higher wind load resistance. If higher wind
load resistance is required, contact Siniat's technical department.
If there are requirements for shear strength, contact Siniat's technical department.
Siniat B.V. ● Oosterhorn 32-34 ● 9936 HD FARMSUM, THE NETHERLANDS
Technical Service +31 (0) 596 – 649
333 www.siniat.se
Page 3 of 3