UK MDF & Chipboard Sizes & Grades

P2 chipboard is general-purpose for dry conditions only (kitchens and bathrooms excluded). P5 chipboard is moisture-resistant, with a green-dyed core to identify it. P5 is required for floor decking in domestic construction per BS EN 312 and is the standard for all structural flooring applications. P5 can withstand intermittent wetting during construction.

Common MDF thicknesses: 3 mm for backing panels and templates, 6 mm for panel inserts, 9 mm for wall panelling, 12 mm for shelving and light doors, 15 mm for cabinet doors and panels, 18 mm for worktops, cabinets and heavy shelving, 25 mm for acoustic panels and heavy-duty surfaces. MDF is available up to 30 mm for specialist applications.

No. Moisture-resistant (MR) MDF has added wax and resin to resist swelling from humidity, but it is not waterproof. It is suitable for kitchens and bathrooms where it may be exposed to occasional moisture but must be painted or sealed. For wet areas, use marine plywood or cement board instead. MR MDF is typically identified by its green-dyed core.

The most common UK sheet size is 2440 x 1220 mm (8 x 4 ft). Larger sheets are available at 3050 x 1220 mm (10 x 4 ft) and 3050 x 1525 mm (10 x 5 ft). Chipboard flooring panels are typically 2400 x 600 mm with tongue-and-groove edges for easy installation at 400 mm or 600 mm joist centres.