Hi Whoever can help
We are currently carrying out retrofit on a 1910 house. Specifically insulating suspended timber floors from the crawl space below.
The timbers and floorboards are all in good condition.
The plan is to:
- draught proof: seal holes around central heating pipes; parge bricks between joists upto and behind floorboards with Diathonite
- use Thermafleece between joists
- cover the Thermafleece on the cold side using a windproof membrane (Thermafleece breather membrane ) taped (Tescon Vana) to the parge (Diathonite) on bricks.
Our conundrum is what to do where the joists sit in the brick wall.
Currently the brick pocket is open all around the joist (except where the floorboards sit above and the joist sits on slate or brick below) i.e. the timber is well ventilated.
Our thinking is that the insulation steps above will effectively put the open space around the joists that were on the cold-side into the ‘warm-side’. At the end of the joist there is only a single brick of the outside wall, so if the space is left open are we creating the potential for condensation?
Would appreciate a view on the following:
Should we leave the space open or fill around the joist?
If we fill what is best to fill with? (in some cases access to the outer most end of the joist is limited).
Hope someone can help, thanks
Don & Helen