External Boards
Boards suitable for external applications.
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How long can I leave Weather Defence™ exposed?
Siniat Weather DefenceTM is water, weather and mould resistant and can be left installed and exposed for up to 12 months on site before you need to complete the final cladding.
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Can I omit my breather membrane when using Weather Defence™?
Siniat Weather DefenceTM does act as a breather membrane when installed and sealed in line with the installation procedure. The board and sealing have been tested to show negligible air leakage (0.002 m3/m2/hr). The prevention of water penetration test demonstrated performance at the highest level - Class W1 to EN13859-2 matching that of standalone
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Is Weather Defence™ Non-Combustible?
Yes, Weather DefenceTM is classed as A1 Non-Combustible according to BS EN13501-1:2007
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What EPDM do Siniat recommend for use with Weather Defence™?
Siniat do not have any specific recommendations for waterproofing products/membrane manufacturers for use with the board. Siniat advise that an appropriate cold-applied sealing methods such as butyl tapes or EPDM (by others) should be used to seal deflection or movement joints created in the board layer, or to infill panel edges to other materials (
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Can hot melt waterproofing systems be used with Weather Defence™?
Siniat do not recommend the use of hot-applied waterproofing materials with Weather DefenceTM . You must only use cold applied waterproofing materials. Gypsum based boards should not be subjected to temperature conditions where the surface of the board is likely to rise above 50°C, as the state of the surface and core can begin to change beyond this
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How should Siniat Bluclad board be fixed?
Siniat does not manufacture fixings for Bluclad. (click link for general information) It is recommended to use a stainless steel fixing suitable for either timber or metal SFS studs. Your preferred fixing suppliers will be able to advise you on suitable fixing for autoclaved fibre cement boards and the substrate. Boards must be fixed back to a suita
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Do the wind loadings stated in the Weather Defence brochure account for internal wind loadings as well as external wind loadings?
The designed for wind load is the maximum magnitude that can be withstood by the Thruwall element. The load can be positive or negative (pressure or suction). Typical design range is 1kN/m2 to 1.8kN/m2 but can be more or less. Internally, unless advised by the project design team, internal pressure is default designed to 200Pa (0.2kN/m2) which is ea
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Does Siniat Weather Defence omit the need for a VCL?
The Siniat Weather Defence board does not act as a Vapour control layer. It does work as a breather membrane which may allow for the omission of a separate breather membrane. If required, a vapour control layer (VCL) should be installed on the warm side of the element. This can be via a Siniat vapour check grade plasterboard or a separate membrane d
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Can a render be directly applied on Siniat Weather Defence board?
Siniat Weather Defence is not suitable to receive a direct render finish. The only product in the range that is suitable for such a finish is the Bluclad product. There is a BBA associated with Bluclad and Weber Rend and general guidance can be found in the Bluclad brochure.
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Where a Siniat Thruwall system interfaces with a Promat encased steel is the complete elevation covered by the Thruwall warranty?
The Siniat Thruwall warranty covers the tested Thruwall system only and does not include any surrounding structural frame even if encased in Promatect fire protection systems. The Promat encasement systems are covered by their own product warranty and system performance is covered by third party certification.
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Does the reverse side of Siniat Weather Defence offer the same weather resistance as the front purple face?
Siniat recommend that Weather Defence is installed the correct way round with the purple side facing outwards. Whilst the grey facia to the back uses the same nonwoven technology as the purple front, the grammage is slightly lower and therefore will not offer the same level of water and weather protection as the front.
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Do you have to line framed opening in the Siniat Thruwall System?
The standard recommendation is that all framed opening with-in Siniat Thruwall systems should be lined with layers of 12.5mm GTEC Weather Defence board to maintain the system performance in these locations. As ever this should be checked and confirmed with relevant window, ducting or firestopping manufacture to ensure that this lining meets their p
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How do you finish Siniat Weather Defence board when it is used for an internal application?
Siniat Weather Defence board can be finished using the following methods: Where the need for an A1 classed plasterboard is required but not for moisture/wet applications, Weather Defence can be used and be finished with the standard Siniat Jointing compounds. Siniat Joint Filler to be used to bed and fill the joint, with the Siniat Joint Cement or S
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Can cavity barriers be directly fixed to Weather Defence?
Siniat general recommendations are to fix 3rd party products through the Weather Defence board into the supporting metal or timber framework behind which will be installed at maximum 600mm centres. It is possible to fix in the board only, for this the correct fixing type and number of fixings used must be correctly to install the product and provide
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How to fix external insulation to Weather Defence board?
Firstly the insulation manufacturers guidance must be considered. They will have a recommended fixing pattern which must be achieved as a minimum. The type of fixing used can be advised by a fixing manufacturer and must be suitable for the insulation in question and the substrate it is fixing through to. Siniat Weather Defence board will be fixed t
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Can Siniat boards be used in semi exposed conditions?
Bluclad is the only product within the Siniat range that can be used in permanent semi exposed conditions. This is available as board only, Siniat have no specific system data associated with it so the design team will need to ensure it is fit for purpose in the system it is to be used in. Siniat Weather Defence (used as a sheathing board to SFS) ca
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Is Weather Defence recyclable?
The core of Siniat Weather Defence is recyclable, however the liner is not. The waste processing plant will separate the liner from the core of the board and process in other waste streams. The Weather Defence core will be recycled as per a gypsum process.
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How should Siniat Weather Defence board joints be treated when used in Thruwall systems?
There are two ways in which the board to board joints in Siniat Weather Defence can be treated as part of the Siniat Thruwall system. Which method is used is dependant on the performance the element is required to achieve. Siniat Weather Defence™ Joint Tape may be used where no fire resistance or acoustic performance is required. This is to achieve
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What Siniat components must be used in the Siniat A1 shaftwall system?
Siniat A1 shaftwall systems are designed to seamlessly interchange with the traditional Shaftwall components and construction method. The only differences include the use of A1-classified plasterboard (EN13501-1), 12.5mm Weather Defence boards to the corridor side, and 19mm Weather Defence board to the shaft side. For full details of the A1 Shaftw
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What fire and acoustic performance is possible with Siniat A1 Shaftwall systems?
The fire and acoustic performance of the Siniat A1 Shaftwall systems are dependent on full system build-up. See the Siniat Drywall Manual -Shaftwall Section for full details. The two system variants available are shown below:
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What is the maximum deflection allowance that can be incorporated within the Siniat A1 Shaftwall system?
The Siniat A1 shaftwall deflection head detail can cater for upto 40mm movement. At construction you will need to understand whether you need to allow for upward and downward movement or just downward and install accordingly, but the maximum range of movement is 40mm. The deflection head configurations are shown below: Please follow the link for f