Timber Sheet Materials

Sheet materials are the boards that make up floors, roofs, walls and decks: OSB for sheathing, plywood for structural work, tongue and groove chipboard for flooring. Grade matters more than most people expect, because the same board in the wrong class fails early. Every sheet stocked here is a load-bearing, humid-conditions grade, chosen to sit inside a real build-up alongside insulation, membranes and tape.

Insulation UK
11mm OSB 3 BOARD 2.44m x 1.22m

£15.29 Ex VAT

In stock
Insulation UK
12mm Chinese Hardwood Faced Plywood 2.44m x 1.22m EN636-2

£22.89 Ex VAT

In stock
Insulation UK
18mm Chinese Hardwood Faced Plywood 2.44m x 1.22m EN636-2

£30.44 Ex VAT

In stock
Insulation UK
18mm OSB 3 BOARD 2.44m x 1.22m

£20.55 Ex VAT

In stock
Kronospan
22mm Kronobuild P5 (Moisture Resistant) Tongue and Groove Chipboard 2400mm x 600mm

£11.40 Ex VAT

In stock
Insulation UK
5.5mm Chinese Hardwood Faced Plywood 2.44m x 1.22m EN636-2

£12.66 Ex VAT

In stock
Insulation UK
8mm OSB 3 BOARD 2.44m x 1.22m

£11.76 Ex VAT

In stock
Durelis
Durelis TG Moisture-Resistant Chipboard 2400 x 600mm 2400 x 600 x 18mm

£10.67 Ex VAT

In stock

What are Timber Sheet Materials?

Timber sheet materials are engineered wood panels made by bonding timber strands, veneers or particles together with adhesive under heat and pressure. They are used across construction for flooring, roof decking, wall sheathing and general structural work.

The three stocked here are the three that do structural work in a building:

OSB (oriented strand board) is made from timber strands laid in layers at alternating orientations, which gives it high shear strength. It is the cheapest structural sheet and is used for wall, floor and roof sheathing.
Plywood is made from thin wood veneers bonded with the grain of each layer turned 90 degrees to the one below. That cross-graining is what makes it stable and strong for its weight. Used for structural decks, flooring and roofing.
Chipboard (particleboard) is made from wood chips bonded in layers. In tongue and groove flooring grade it is the standard board for domestic floors.

MDF, hardboard and marine plywood are not stocked. If that is what you need, this is not the range.

Grades Explained: The Bit That Actually Matters

Two boards can look identical and be rated for completely different jobs. The grade is the specification, not the material.

Board	Grade stocked	What the grade means
OSB 3	OSB/3 to EN 300	Load-bearing, for use in humid conditions
Hardwood faced plywood	EN 636-2	Plywood for use in humid conditions
T&G chipboard	P5 to EN 312	Load-bearing, for use in humid conditions

Every board in this range is a humid-conditions, load-bearing grade. That is deliberate. These are boards for floors, decks and sheathing on real sites, where they will meet damp during the build and need to carry a load afterwards.

Is Any of This Waterproof? No.

This is worth being straight about, because a lot of listings are not.

Humid conditions means the board will handle occasional wetting, high humidity and exposure during construction. It does not mean the board is waterproof, and it does not mean it can be left permanently exposed outdoors.

Exterior grade (EN 636-3 in plywood) is a step above and is intended for external use. Marine plywood (BS 1088) is different again, and is a specific spec for boat building that is routinely, and wrongly, used as a synonym for "waterproof plywood".

None of the boards here are marine ply, and none are permanently weatherproof. If a sheet is going to live outside in the rain, it needs the right grade and a proper finish, and it is worth asking rather than guessing. Call us on 03003 034 578.

Which Sheet Material Do I Need?

Job	Board	Why
Wall, roof or floor sheathing	OSB 3, 11mm or 18mm	Structural, humid-rated, cheapest per sheet
Structural deck or roof deck	Hardwood faced plywood, 12mm or 18mm	Stronger and more stable than OSB for its thickness
Domestic floor, including over insulation	P5 T&G chipboard, 18mm or 22mm	Interlocking edges, moisture-resistant flooring grade
Thin sheet, lining or backing	5.5mm hardwood faced plywood	Thinnest sheet stocked
Cheapest structural sheet	OSB 3, 8mm	Lowest cost per square metre in the range

What is the Cheapest Sheet Material?

OSB 3, on every measure. It is significantly cheaper than plywood of the same thickness and carries a load-bearing, humid-conditions rating, which is why it is the default for sheathing on most sites.

Plywood costs more and earns it where you need strength and dimensional stability in a thinner board, or a better face. Chipboard sits in the middle and is the standard choice for flooring specifically, because of the tongue and groove edge.
The cheapest board is not the same as the cheapest job. A sheet in the wrong grade that has to come back up is the most expensive option there is.

Standard Sheet Sizes

OSB 3 and hardwood faced plywood are stocked at 2440mm x 1220mm, which is the standard 8ft x 4ft sheet.

Tongue and groove chipboard flooring is stocked at 2400mm x 600mm, which is the standard flooring board size, sized to be handled and laid by one person.

Full sheets need a van or a trailer. Bespoke cutting is available if you would rather have the boards cut before they arrive.

Why Choose Insulation UK for Timber Sheet Materials?

Structural Grades Only with OSB/3, EN 636-2 plywood and P5 chipboard, all load-bearing, humid-conditions boards. No decorative panels, no filler.

The Board and the Build-Up in One Order so the OSB, the insulation, the DPM and the tape arrive together rather than from four suppliers.

Bespoke Cutting Available if you need the sheets cut to size before delivery.

Competitive Trade Pricing with no minimum order value.

Fast UK-Wide Delivery from our distribution centre in Rotherham, with free shipping on orders over £500 (ex VAT).

Help and Advice with over 50 years in the industry behind the team. Tell us the job and we will tell you the grade.