Redoing dormer cheeks and front

[0Floz0]

Hi all

Had a good read through the many dormer threads on here but all seem to be brand new dormers or lead based approaches.

To keep it brief. Whoever did the dormer on my house 20 years ago did a cowboy job. I’ve only been in this house 3 years but they used the hollow soffit board vertically (it’s not rated for vertical) and didn’t put any trims on (or they did and they’ve not lasted). This combined with no drip trays over the windows means the studs have rotted through moisture ingress.

I’ve got to rip it all out and start again (but hoping most of internal studs are ok). I’ve got upvc cladding (proper stuff not the soffit stuff).

Questions are:

Do I use osb or ply? How thick should I go?

Im going to use tyvek house wrap over the osb or ply. I’ll then fix tile lathes as battens over the house wrap for the cladding to go onto. Is that the right approach?

The weather has been a bit rubbish recently. As long as I can rip it out and get it all boarded back over and the house wrap on before any rain I assume that’ll be fine? Wary of getting moisture on anything before the cladding goes on.

Many thanks

 

[noseall]

Hi all

Had a good read through the many dormer threads on here but all seem to be brand new dormers or lead based approaches.

To keep it brief. Whoever did the dormer on my house 20 years ago did a cowboy job. I’ve only been in this house 3 years but they used the hollow soffit board vertically (it’s not rated for vertical) and didn’t put any trims on (or they did and they’ve not lasted). This combined with no drip trays over the windows means the studs have rotted through moisture ingress.

I’ve got to rip it all out and start again (but hoping most of internal studs are ok). I’ve got upvc cladding (proper stuff not the soffit stuff).

Questions are:

Do I use osb or ply? How thick should I go?

Im going to use tyvek house wrap over the osb or ply. I’ll then fix tile lathes as battens over the house wrap for the cladding to go onto. Is that the right approach?

The weather has been a bit rubbish recently. As long as I can rip it out and get it all boarded back over and the house wrap on before any rain I assume that’ll be fine? Wary of getting moisture on anything before the cladding goes on.

Many thanks

12mm minimum thickness. We use ply. Breather then batten - ok. Don't forget to insulate.

 

[0Floz0]

12mm minimum thickness. We use ply. Breather then batten - ok. Don't forget to insulate.

Thank you. I’m hoping to reuse the insulation as that looks ok from the inside. But I’ve got some Pir spare should I need to insulate. Good point though. Do you need an air gap for the insulation?

I’ll go for the ply option. If it’s wbp do I need to seal the cut edges? I’ve got some Sbr for some tiling so I could use that if i need to seal?

Thanks