Siniat Weather Defence™ Plasterboard 12.5mm - 1200 x 2400 mm

• As a general external sheathing board
• As an external sheathing board substrate for insulation boards

What is Siniat Weather Defence™?

Siniat Weather Defence™ is a high-performance external sheathing board designed for use in steel and timber frame construction. It features a water-repellent facing and provides excellent moisture, weather and fire resistance.

What size is Siniat Weather Defence™?

This product is supplied as a 12.5mm thick board measuring 1200 x 2400mm, with square edges.

Is Siniat Weather Defence™ suitable for external use?

Yes. Weather Defence™ is specifically designed for external sheathing applications, including use behind rainscreen, insulated render, brick and block façade systems.

Is Siniat Weather Defence™ waterproof?

Weather Defence™ is highly moisture resistant and designed to provide weather protection. It can also be left exposed during construction for up to 12 months, when installed as part of the appropriate system and in accordance with Siniat's requirements.

Is Siniat Weather Defence™ fire resistant?

Yes. Weather Defence™ is A1 non-combustible according to EN 13501-1, providing the highest Euroclass reaction-to-fire classification.

Can Siniat Weather Defence™ be used on timber and steel frames?

Yes. It is suitable for external sheathing applications on both timber and steel frame construction, subject to the requirements of the relevant system.

Is Siniat Weather Defence™ easy to cut?

Yes. The board can be cut using the score-and-snap method, similar to conventional plasterboard, meaning specialist power-cutting equipment is generally not required.

Does Siniat Weather Defence™ need a breather membrane?

Depending on the construction system and design, Weather Defence™ can eliminate the need for a separate breather membrane because it provides weather protection and functions as a rigid air barrier. Always check the requirements of the specified system before installation.

Is Siniat Weather Defence™ mould resistant?

Yes. The board is designed to resist mould growth and has a moisture-resistant gypsum core and facing. Siniat's technical data states that the board is mould resistant with zero biodegradability.

What is the weight of a 12.5mm Siniat Weather Defence™ board?

The board has a nominal weight of approximately 10.8kg/m², with an individual 1200 x 2400mm board weighing approximately 31kg.

What fire classification does Siniat Weather Defence™ have?

Siniat Weather Defence™ has a Euroclass A1 reaction-to-fire classification and is classified as non-combustible.

What standards does Siniat Weather Defence™ comply with?

The 12.5mm Weather Defence™ board is manufactured to BS EN 15283-1, including classifications GM-F, GM-H1 and GM-I, and is CE marked accordingly.

Can insulation be installed over Siniat Weather Defence™?

Yes. Weather Defence™ can be used as an external sheathing board substrate for insulation boards and is suitable for certain insulated render and external insulation systems. The complete system specification should always be followed.

What is Siniat Weather Defence™ used for?

Typical applications include external sheathing for:

• Timber frame buildings
• Steel frame construction
• Rainscreen façade systems
• Insulated render systems
• Brick and block façade systems

How should Siniat Weather Defence™ be sealed?

For a weathertight installation, Siniat specifies appropriate Weather Defence Joint Tape or GTEC Fire Rated Silicone Sealant, depending on the required system performance.

Where can I buy Siniat Weather Defence™ 12.5mm?

You can purchase Siniat Weather Defence™ 12.5mm – 1200 x 2400mm from National Insulation Supplies. It is a suitable choice for contractors and building professionals looking for a robust external sheathing board with high moisture resistance and A1 non-combustible performance.