Retrofit Cavity closer around window - advice / suggestions please

[SouthDrive]

Hi,

Whats the best solution regarding cavity closing without taking the window out? - I was going to put a layer of mortar on the inner leaf and set a cavity closer into it, then do what I can to seal it on the outer leaf with some silicon sealant
Any advice


Id like to leave the window reveals intact aswell - might revisit them in the summer but for now id rather not disturb.

Thank you
Will

 

[Ivor Windybottom]

Is there a sliver of a gap under the window? If so then trim down a cavity closer so it has a shorter side that pops into that gap.

If there isn't a gap then try to make one.

Worst case, trim the cavity closer so it merely butts up to the inside of the window frame.

Resist the urge to squirt a load of expanding foam in, it can bridge damp.

 

[Ivor Windybottom]

Actually, looking at the shape of the top of the wall, a cavity closer probably wouldn't do anything. It looks like there's no wall behind the plaster for the top inch or so. Is this right?

In which case it needs a wall there first.

 

[jono_h]

Fold some DPM into the cavity, then stick some Celotex in there, with a bit of foam to hold it in place?

 

[Ivor Windybottom]

Fold some DPM into the cavity, then stick some Celotex in there, with a bit of foam to hold it in place?

It might need some interesting trimming!...

I'm assuming that notch in the middle of the photo above was where there was a bit of wood under the old sill?

I'd say SouthDrive's idea of mortar behind the plaster then a cavity closer is spot on.

 

[noseall]

Hi,

Whats the best solution regarding cavity closing without taking the window out? - I was going to put a layer of mortar on the inner leaf and set a cavity closer into it, then do what I can to seal it on the outer leaf with some silicon sealant
Any advice


Id like to leave the window reveals intact aswell - might revisit them in the summer but for now id rather not disturb.

Thank you
Will

View attachment 426160

Foam in a length of PIR cut to suit with some DPC stapled to the cold side. Once it has set and stabilised those blocks, you can trim the old plaster etc. Friction fit the PIR (we make PIR wedges) then foam it.

 

[cdbe]

Foam, baby, foam.

Use low expansion stuff and you could probably stick the window board on at the same time, have a few bricks to hand to stop it floating away before it sets.