Mould under 1930 bay window

[JohnD]

I wouldn't cut the felt, because it needs to be nailed to the outer face of the timbers, which you can't do from outside. Your membrane you can fold and staple into place. It is possible to patch roofing felt with a black tarry compound used like glue, don't know what it is called. Ask on the Roofing section,

 

[marc.knuckle]

I wouldn't cut the felt, because it needs to be nailed to the outer face of the timbers, which you can't do from outside. Your membrane you can fold and staple into place. It is possible to patch roofing felt with a black tarry compound used like glue, don't know what it is called. Ask on the Roofing section,

How about the clout nails? I don't want to get ones too long and pierce something in the window.
Thanks mate

 

[JohnD]

You can get half- inch ones

Galvanised Extra Large Clout Nails - 13 x 3mm - 500g | Wickes.co.uk

Galvanised Extra Large Clout Nails - 13 x 3mm - 500g

www.wickes.co.uk

 

[marc.knuckle]

Right. I'll take a photo in a bit but i did the wood treatment, i added OB1 on top of the lead then nailed it up to make sure that if moisture got in below the window from the outside it wouldn't get past the silicone.

Now i have added two 1 inch layers (i had it left over from another job) of the foil backed insulation board, celetex i think or something like that.

Now I'm about to get the moisture resistant plasterboard. However i don't know if i should somehow try to bend the board around the curve or cut it into the 10 narrow sections the bay is in or if that somehow compromises the moisture resistant benefit of the board?

 

[Deluks]

If you don't insulate over the timber studs, they may end up showing through the plasterboard.

Use insulated plasterboard, cut mitres where they meet over the studs.

Staple some aluminium tape, sticky side out, over the studs before fixing. That will ensure airtightness where the boards join.

Your window board can sit onto the insulated plasterboard.

 

[JohnD]

You can steam or spray and bend ordinary plasterboard and fix it to a curve. When it dries it will hold the shape. I have some in a half round in a stairwell, the radius is the staircase width.

I did not do it myself but one of the builders told me how it was done.