What is Rockpanel?
Rockpanel is a brand name for facade boards made of heavily compressed stone wool bound with a synthetic resin and finished with a coating on the face. They are produced by Rockpanel, part of the ROCKWOOL Group. In practice the name — like “Trespa” — is often used loosely for any flat facade board, although it refers to a specific product.
Properties
- Make-up — basalt stone wool fibres compressed into a dense, rigid board, with a painted or coated face.
- Thickness — 8 mm is standard; some ranges also come as a 9 mm A2 variant.
- Board sizes — common formats are 2500 and 3050 mm long by 1200 or 1250 mm wide.
- Weight — in the order of 11 kg/m², appreciably lighter than fibre cement or natural stone.
- Reaction to fire — varies by range. The A2 versions are classified A2-s1,d0 to EN 13501-1: non-combustible, very limited smoke, no flaming droplets. Always check the declaration for the specific product you buy.
- Bendable — the boards can be curved to a generous radius, which suits curved fascias and rounded facade panels.
Where they are used
Widely used on dormers, fascias, bargeboards, verges, roof edges, gable ends, soffits and as complete ventilated rainscreen cladding. They are popular in refurbishment because they are light, available in many colours and wood finishes, and can be worked with ordinary woodworking tools.
Installation rules that matter
- Always install ventilated. There should be a cavity behind the board of normally at least 20 mm, with openings at both bottom and top. Without ventilation the board moves and moisture stays trapped behind it.
- Allow for movement. The boards expand and contract with temperature and moisture. Keep the manufacturer’s specified joint width between boards and around fixings; butting them tight leads to bowing and cracking.
- Fix as specified. Usually with proprietary colour-headed nails or screws onto timber battens, or bonded with an approved adhesive system. Never fix rigidly in a way that prevents movement.
- Seal cut edges. Sawn edges are unfinished; treat them with the matching edge sealer, especially at the bottom where water runs off.
- Cut with a fine-toothed blade and use extraction; stone wool dust is fine and abrasive.
Rockpanel installation checks
- Ventilated cavity behind the board: Normally at least 20 mm, with openings at both bottom and top.
- Joint width kept: The manufacturer's specified joint width between boards and around fixings; butting them tight leads to bowing and cracking.
- Fixings allow movement: Usually proprietary colour-headed nails or screws onto timber battens, or an approved adhesive system; never fix rigidly in a way that prevents movement.
- Cut edges sealed: Treat sawn edges with the matching edge sealer, especially at the bottom where water runs off.
- Cutting: Use a fine-toothed blade and extraction; stone wool dust is fine and abrasive.
Related terms
- Facade cladding
- Mineral wool
- Cavity wall
- Dormer
- Fire classification
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.