RCM Y-Wall 2400mm x 1200mm x 12mm

Y-wall Sheathing Board is a calcium silicate cement-based board intended for use as a fire-rated sheathing/building board.

Composition and appearance

Material composition: calcium silicate cement-based board.

Appearance: light grey/yellow, with a smooth front face and a textured back face.

Sizes, thicknesses and dimensional tolerance

Standard sheet size: 2400mm x 1200mm, supplied in a 12mm thickness. Corresponding nominal weights are 7.2kg/m² (6mm), 10.8kg/m² (9mm), 14.4kg/m² (12mm) and 18kg/m² (15mm).

Dimensional tolerance: length ±3mm, width ±3mm, thickness ±0.5mm.

Declared technical performance

Reaction to fire: Class A1 to BS EN 13501-1.

Nominal board density: ≥1200kg/m3.

Bending strength (modulus of rupture): 9-12MPa to BS EN 12467.

Modulus of elasticity (MoE): 4000MPa.

Mechanical resistance: Class 3.

Thermal conductivity: ≤0.23W/mk.

Water content: ≤10%. Moisture movement: ≤0.25%. Moisture resistance: Class A to BS EN 12467.

Performance testing to BS EN 12467 is stated as Pass for heat-rain, warm water, freeze-thaw and soak-dry performance.

Exposure: can be left exposed for up to 12 months when board joints are suitably sealed.

Fire resistance information stated

The document states the following fire resistance outcomes (outside to inside), subject to the referenced test standards:

• BS EN 1364-1 (non-loadbearing): achieving 120 minutes integrity and insulation.
• BS EN 1365-1 (loadbearing): achieving 120 minutes integrity and insulation.
• BS 476: Part 22 (non-loadbearing): achieving 60 minutes integrity and insulation, and achieving 90 minutes integrity and insulation.
  
  

Environment and intended exposure conditions

The board can be left exposed for up to 12 months when joints are suitably sealed. It is intended for applications where it may be subject to heat, high moisture and severe frost.

Installation and handling considerations

Installation is stated as for a competent builder or contractor experienced with this type of product, with the design and method of installation checked by a suitably qualified and experienced individual.

Cutting: the board can be cut with a fine tooth hand saw or power saw, with suitable dust control measures and appropriate personal protective equipment (for example, safety glasses, gloves and respiratory masks) and in accordance with health and safety regulations. Damaged boards must not be used.

Framing: framing grade timber studs or galvanised steel framework should be provided at a maximum 600mm centres for single-layer partitions. The frame must be structurally sound and constructed in accordance with relevant national Building Regulations and Standards.

Water protection and detailing

The board should be treated as a conventional sheathing board for detailing and damp-proofing at openings, eaves and sole plate, and for the fixing of wall ties. Where required by design, a breather membrane must be in accordance with BS5250:2011. The outer weatherproofing should have adequate resistance to wind-driven rain, particularly in regions classified as severe exposure.

Fixing and jointing

Boards are fixed to steel or timber studs using specified screws, with screws flush-fitted (not overtightened), positioned at least 12mm from board edges and at least 50mm from corners. Subsequent boards are installed with a 2-5mm gap between boards.

Fixings stated:

• Steel frame: Ø4.8x38mm FIX006 self-drilling drill point winged.
• Timber frame: Ø4.2x42mm FIX005 self-drilling.

Fixing layout: maximum 600mmx300mm grid pattern is stated, and boards are stated to be installed in a brick bond pattern in accordance with the manufacturer's recommendation.

Jointing stated:

• Non-fire-rated walls: tape over board joints using DAFA UV tape or ME315 tape.
• Fire-rated walls: fill board joints with NULLIFIRE fire-rated silicone sealant.

Air tightness: apply the joint seal kit over the joints; for fire-rated walls, use NULLIFIRE within joints as stated above.

Inspection

The document states completing visual inspections to ensure the product is installed correctly, with each area inspected and recorded as installation progresses.

Technical Data