Structural thermal roof decking

OSB is made of small rectangular shaped wood chips from small resinous trees, which are bonded into a panel form with wax and synthetic resin. OSB boards do not have the disadvantages typical for solid wood, such as knots, and cracks or, in the case of softwood, susceptibility to damage and deformation. OSB simply have greater strength then traditional wood.

This is a reason why OSB is becoming popular. Not only they are used for finishing flats and houses but it turns out that they are also used for roof decking.


corner of osb board











Flat roofs have been common in construction for the last 150 years. From the 1950s right up to the 1970s flat roof properties and flats were quite popular, many were built and are therefore found throughout the UK.
The current target U-value for new or replacement flat roofs should be 0.18W/m²K. 
For roof construction project, it is worth choosing the best and most advanced solution that brakes magic U-value point. When building a flat roof, we must also take into account the load parameters. OSB panel will work best here.

Roofing Board is the ergonomic solution for fast and safe roof decking. OSB Plydeck has a low thermal conductivity, minimising the thickness required to achieve best U-value.

OSB deck is relatively inexpensive compared to other building materials. Once installed, panels deliver unrivaled insulation and airtightness, which reduces energy costs over the building’s lifetime.
A build-up of structural deck, vapour control layer, PIR (polyisocyanurate) insulation and waterproofing offers reliable performance for the lifetime of the waterproofing membrane.

What is OSB Deck?

Ply-Deck Insulation Decking is a three-in-one solution designed to provide decking, vapour control layer and high levels of thermal insulation in one easy applicable product.
OSB deck consists of a core of PIR (polyisocyanurate) foam with laminated 9mm Oriented Strand Board (OSB) top and a bonded foil facing on the underside.
The gas filled cells give osb deck high thermal performance and strength while the foil facing has a very high vapour resistance.


How to install OSB DECK?

OSB deck should be fixed to joists set at a maximum of 600mm centres, with the timber side uppermost and the board laid with the long edge running along the joist. Where an overall vapour control layer is required, this should be achieved by applying a continuous bead of mastic to the upper surface of all supporting timber.

Board should be laid onto the mastic and fixed with Helical Flat Roof Nails. The nails should be long enough to allow a minimum 35mm penetration of the supporting timber. Helical nails should be positioned not less than 10mm from the edge of the board or 50mm from the corner. OSB panels should be lightly butted. All edges must be supported by a minimum of 20mm bearing onto the face of the supporting timber.


corner of 9mm osb board bonded to pir insulation











What is the common size of insulated OSB used on roof decking?

It can be assumed that the common thickness is 129 mm



The product is stable, rot proof and durable and will remain effective as an insulation system at least as long as that of the waterproof covering.

Themal conductivity

The thermal conductivity of the foam is 0.022 W/mK.
The thermal conductivity of the OSB is 0.14 W/mK


Wide range of thicknesses available

 24mm, 29mm, 34mm, 39mm, 44mm, 49mm, 54mm, 59mm, 69mm, 74mm, 79mm, 84mm, 89mm99mm, 109mm, 119mm, 129mm, 139mm, 149mm, 159mm, 174mm.