Subframe for fibre cement panels

Subframe for fibre cement

Fibre cement boards are made from cement, mineral fillers and cellulose or synthetic fibres, then pressed and cured. They are non-combustible in most grades, impact resistant and dimensionally stable, so they are a common choice for schools, offices and housing where a robust, matte, mineral finish is wanted without the cost of stone. Boards come in plain colours, painted and through-coloured versions and some with textures.

Fixing options

• Visible fixing with coloured rivets or screws, with the pattern forming part of the design
• Concealed fixing with back anchors or clips on horizontal rails
• Adhesive fixing for selected products

Weight is moderate, normally in the range of 14 to 20 kg/m2 depending on thickness, so brackets need to be chosen with care. Vertical rails are placed at board joints and at intermediate points, since fibre cement is stiffer but more brittle than HPL or composite.

Design points

• Hole positions and edge distances are strict, and holes are drilled oversize in sliding zones to avoid cracking.
• Boards absorb a little moisture, so the cavity and edge sealing are important, and cut edges should be sealed according to the manufacturer's rules.
• Expect limited bending, which restricts use on curved walls.
• Horizontal joints may be open, closed with a profile or covered, depending on the system.
• Use thermal breaks under brackets.
• Take care of dust during cutting; cutting is best done at a workshop.

Fibre cement helps in fire design, but in Georgia the complete wall above 12 m is reviewed under Chapter 14 of the Building Safety Rules, so insulation and cavity barriers are included.

Pricing is on request. Send us your drawings and we will prepare a board layout and calculation.

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