Tongue-and-groove roof sheathing panels, G4-3

Underlay tongue-and-groove panels from Norra Timber provide a strong, stable and efficient solution for roof decking applications. Manufactured from Northern Swedish spruce and graded to G4-3 quality, they are designed for dependable performance in demanding conditions. Norra Timber roof sheathing panels are assembled with crimped metal nail plates, allowing them to be handled from either side without coming apart.

Product characteristics

Save time and money with roof sheathing panels from Norra Timber. In Sweden, the roof sheathing panel, also known as a “råspontlucka”, has become the most common product for roof decking. It is considerably more efficient than installing individual tongue-and-groove boards because each panel covers a width of 540 millimetres.

Choosing a painted, factory-undercoated version saves even more time.

Making construction easier and more efficient

Norra Timber roof sheathing panels are made from slow-grown northern Swedish spruce with close annual rings, providing durable and highly stable roof decking beneath roofing felt, tiles and sheet metal. One face of the panel is finely grooved to remove nutrients from the surface and thereby reduce the risk of mould growth and discolouration.

All our roof sheathing boards are end-matched, so joints do not have to fall on the rafters and the full board length can be used. This makes installation more efficient.

Easy installation of roof sheathing panels

Norra Timber roof sheathing panels are assembled with crimped metal nail plates, allowing them to be handled from either side without coming apart.

Install the panel with its best face down and with the grooved edge facing down the roof slope. Drive the panels tightly together.

Remember that roofs must always be covered to protect them from moisture while installation work is in progress.

For visible eaves and exposed soffits, we recommend eaves panels in grade G4-2. This higher grade is better suited to painting and therefore also gives a better visual result.

The completed roof decking must not contain protruding nails, screws or other objects that could damage sheet-metal roofing, waterproofing membranes, roofing underlays or similar materials.

Form butt joints over supports, with no more than every second joint positioned over the same support. The maximum centre-to-centre spacing between supports is 1,200 millimetres. We recommend hot-dip galvanised nails measuring 2.8 × 75 millimetres or 2.3 × 60 millimetres.

Panels made from 95-millimetre boards are fixed with one nail per board. Panels made from 120-millimetre boards are installed with the joint over the rafter and fixed with two nails per board.