Timber Wall Overhang Base To Make Room For Insulation/Cladding?

4 May 2016
Reaction score
United Kingdom
Hi. I initially designed the wall to be double 12mm ply/OSB on the exterior totaling 24mm but now found out that timber is a thermal "weak spot" in terms of insulation so figured it would be better to add exterior insulation to the building wedged between the ply/OSB?

Here's what I got:



So the timber is build on a single skin brick layer. There is already overhang on the inside of about 20mm.

Am thinking of splitting those 2 12mm sheets and wedging insulation board in between.

Complete with the battens and render cladding this would leave a pretty big overhang.

Layers would go like this:


Would the bricks and concrete slab and timber framework be able to take the weight of this overhang?

That piece of "wood" you see in the top pic would be screwed to the base of the timber framework so the Celotex and plywood can rest on it without putting too much pressure on the edge of the brick.

Also the framework studs are 400mm spaced and will be filled with acoustic rock wool which isn't as thermally good, hence the added external PIR boards idea.

Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links