OSB, MDF & Chipboard

What we supply

• OSB3Load-bearing board for humid conditions: floors, roofs, sheathing and site hoardings.
• OSB3 tongue and grooveFlooring-grade OSB that locks together over joists.
• Standard MDFSmooth, stable sheets for internal joinery and shelving.
• Moisture-resistant MDFFor bathrooms, kitchens and window boards.
• P5 chipboard flooringMoisture-resistant tongue-and-groove floor decking.
• HardboardThin sheets for protection and backing.

Sizes and specifications

OSB	OSB/3 to BS EN 300
Chipboard flooring	P5 to BS EN 312, 18 and 22 mm
MDF	BS EN 622-5; MR grades for damp areas
Sheet sizes	2440 × 1220 mm; flooring 2400 × 600 mm

Sizes and standards are typical for the UK market; exact figures depend on the manufacturer and are confirmed on your quote.

Common uses

• Floor decking
• Roof and wall sheathing
• Joinery and shelving
• Site hoardings

Choosing OSB, MDF and chipboard

OSB or plywood?

OSB3 is usually cheaper and fine for most structural decking in humid conditions. Plywood is stiffer, takes fixings near edges better and performs better where it may get wet.

Which flooring?

P5 chipboard flooring is the standard moisture-resistant floor deck. 18 mm is common at 400 mm joist centres and 22 mm at 600 mm centres, but follow the maker's span table.

Cutting MDF safely

MDF dust is fine; cut with extraction and wear suitable respiratory protection.

How it arrives on site

Sheets come in packs on the lorry bed, crane-lifted or hand-offloaded. We agree the drop point and offload method when we price your order. Read more about how delivery works.

How much do you need?

Decking 24 m² with 2440 × 1220 mm sheets takes 9 sheets including 10% for cutting. In P5 chipboard flooring (2400 × 600 mm) the same floor takes 19 boards.

OSB, MDF & Chipboard: questions

What is OSB3?

OSB3 is oriented strand board graded for load-bearing use in humid conditions under BS EN 300. It is the common grade for floors, roofs and sheathing.

What chipboard flooring should I use?

P5 moisture-resistant tongue-and-groove chipboard. 18 mm is common on joists at 400 mm centres and 22 mm at 600 mm centres.

Can OSB get wet?

OSB3 copes with humid conditions and short exposure during construction, but it should not be left in the rain for long or used where it stays wet.

Is MDF waterproof?

No. Moisture-resistant MDF handles humid rooms better than standard MDF but must still be sealed and kept out of direct water.

What size are flooring boards?

Chipboard flooring is commonly 2400 × 600 mm with tongue-and-groove on all four edges.