Window Reveal Question

[john0wingnut]

I currently have 2G uPVC windows, which I am going to change to AluClad 3G - quotes have been requested from the usual suspects.

 

Now, I've been investigating our master bedroom due to drafts and mold on window and door internal reveals etc, and thus I ripped off the plasterboard/ window sill.

 

What Ive found is the current windows are poorly installed as I can see daylight in places around the frame and a section of cavity closer was missing / were poorly fitted.

 

The lintels over the windows / patio door are the continuous metal type, and if memory serves me well, this means that one should use some form of insulation between the lintel and the reveal - eg PIR backed plasterboard.

 

Given what Ive found here, Im concerned the reveals/openings in other rooms potentially have issues as well. The =uPVC is currently 70mm and most aluClad timber is wider, so reveals will need to be cut back anyway, and I think most get mounted on straps screwed into the inner block, which would probably mean removing or damaging the plasterboard anyway to allow proper window installation.

 

So, if others where in my shoes, would you just go around and pull the inner reveals off and fix any potential issues prior to the windows turning up, then put in new PIR backed plasterboard, once the windows are fitted, or leave it until the uPVC windows are taken out to see whats what, then take it from there?

[Russdl]

I’d pull the reveals off to see what’s what and then expanding foam any holes as a stop gap. 
 

I presume your preferred supplier, when chosen, will do a survey so they will see what they have to work with and maybe advise on any work required prior to them installing the 3G windows.
 

Once they’ve installed the windows  (a good idea to watch them like a hawk) get them to fix any cock ups and then put the reveals back. 
 

Thats what I would do but hopefully wiser folk will be along soon with further advice. 

[Mr Punter]

+1 Strip one of them off, as well as the cill.  They will probably all be the same.  What insulation you can get in will depend on the windows profile.  Even 20mm PIR will be better than none.  All around.  Fit the windows close the the insulation zone.  If it is cavity wall, 80mm back from the outside of outer leaf.

[MikeGrahamT21]

Just a note on your lintels, I don’t think using PIR backed plasterboard is a good idea, and I’m pretty sure it could be a dangerous move. Use fireline plasterboard (1 layer) or normal plasterboard (2 layers) on your lintels

 

i forget what amount of fire protection you need on lintels, but make sure you adhere to it

Edited January 9, 2021 by MikeGrahamT21

[Russell griffiths]

I think you need two different trades here, your window fitters won’t be interested in fixing any poor work unless they have quoted for it previously, they will want to chuck them in and foam them up and run away, they will probably be subbie fitters working for the window company. 

I would rip out everything first and see what you are dealing with then work out a plan on how to fix the reveals, if that means another builder then he needs to be there to fix the mess as the windows are ripped out. 

[john0wingnut]

Hi all

 

Thanks for the replies. I'll go around and rip them all off and see whats what then. Not such a bad thing, as the misses would like Oak window sills anyway. I'll just have to be careful when pulling the bead edges off, as I've damaged some of the plasterboard on the wall above the window in this room, as I didnt notice nails through it....

 

Ive just had a 12 pack of illbruck 2 in 1 airseal foam delivered, so I can fill all around the window opening between the block and plaster board.

 

With regards to the Lintels,  and  internal reveals, I looked through a document by LABC called "Builders Book - An illustrated guide to building energy efficient homes" and it advises the use of insulated backed plasterboard, to avoid cold bridging, so figured I would use that when replacing the removed plasterboard, and maybe 15mm PIR or XPS under the window sill.

 

Im doing the repair work myself, well, except the plastering that is.

 

John