Insulating Wooden Bay Window

SachaJ

Hi all.....

I'm currently renovating a 1950's house prior to moving in. Plastering, floors, insulating suspended floors, wiring, kitchen etc....

The house has a bay window that that extends the full height. IE. In a downstairs room and extends up to be part of the master bedroom. I've discovered this week that underneath the window downstairs is block construction but everything above that is wood with zero insulation. So from above the bay window downstairs up to the roof, the part extending out is built up of wood and pebble dashed externally.

I cut out a hole upstairs (through plasterboard) and it's about 12 inches of nothing before I hit the wood so no insulation.

My question is, how do I insulate the window?

I have a roll of Solitex Plus that I'm going to use for insulating the suspended floors downstairs. I was thinking of taking off all the plaster board and covering the external side wood with the Solitex Plus before filling with Earthwool (have 9 rolls in the garage).

Would that work ok? Chances are that there is already a waterproof membrane between the external wood and pebble dash as the wood looks dry as a bone so I might not need to re-line.

See below for a photo. So everthing above the downstairs window is constructed from wood with no insulation and pebble dashed over. (Just the actual sticking out part is wood. Block with a 50mm cavity to the left and right)

BryanF

dont presume that the current build-up has felt between wood and plaster,but it may well have.

id be carefully considering the due point/ interstitial condensation risk that increased insulation may cause

whatever you do,you'll be wanting a vapour barrier on warm side of insulation also

SachaJ

BryanF wrote: »

id be carefully considering the due point/ interstitial condensation risk that increased insulation may cause

Would the Solitex Plus not sort that issue for me? It's one way breathable - lets moisture out but not in. In this case could it cause condensation on thwe wood?

BryanF wrote: »

whatever you do,you'll be wanting a vapour barrier on warm side of insulation also

Really? I thought as with insulating the suspended floors that I just needed the Solitex Plus on the cold side.

BryanF

SachaJ wrote: »

1. Would the Solitex Plus not sort that issue for me? It's one way breathable - lets moisture out but not in. In this case could it cause condensation on thwe wood?
2. Really? I thought as with insulating the suspended floors that I just needed the Solitex Plus on the cold side.

1. its not about the solitex, where does the moisture come from? the internal enviroment
2. yes really, in both instances you need the addition of a VB on the inside

we'd need to see the details and treatment at the junctions to consider this fully

SachaJ

Some photos.

Upstairs window


Below upstairs window


Above upstairs window


Downstairs window


Close up of above downstairs window