Foil back plasterboard

[Hitch]

I want to board the walls in our conservatory...
I plan on putting 2x1 battens and 25mm cellotex, with foil backed plasterboard over... Because of the uneven stonework I anticipate there will be a bit of an air gap behind the cellotex and battens.

The walls are dry apart from one little bit, where the window meets the wall. When it's really wet you can see it, as per picture. That's as bad as it gets.

Do we think a little air gap behind will be fine to allow it to dry out as and when it gets a touch damp, and not lock in the moisture and cause issues..?

Worth bothering with foil backed board, seeing as I'm going to use cellotex? Just go over the insulation joints and over the battens with foil tape..? Same difference as far as I can see.

Any thoughts... ?

 

[eLuSiVeMiTe]

I want to board the walls in our conservatory...
I plan on putting 2x1 battens and 25mm cellotex, with foil backed plasterboard over... Because of the uneven stonework I anticipate there will be a bit of an air gap behind the cellotex and battens.

The walls are dry apart from one little bit, where the window meets the wall. When it's really wet you can see it, as per picture. That's as bad as it gets.

Do we think a little air gap behind will be fine to allow it to dry out as and when it gets a touch damp, and not lock in the moisture and cause issues..?

Worth bothering with foil backed board, seeing as I'm going to use cellotex? Just go over the insulation joints and over the battens with foil tape..? Same difference as far as I can see.

Any thoughts... ?

View attachment 374763

Address the ingress. Probably just a matter of pulling out the mastic and resealing it. Not got much depth to play with for battens and board?

 

[Hitch]

It's a mortar fillet taking up the discrepancy in the stonework, thats getting wet, mastic is fine on the outside.

Don't really want to go much further, or it starts getting too close to the edge of the glazed part of the frame.

 

[dan treg]

i would imagine you know but you could just use insulated plasterboard and just dot and dab it so no cold bridging effect

 

[eLuSiVeMiTe]

It's a mortar fillet taking up the discrepancy in the stonework, thats getting wet, mastic is fine on the outside.

Don't really want to go much further, or it starts getting too close to the edge of the glazed part of the frame.

Dry above the line?

I'd pull the mastic and redo myself.

 

[Hitch]

i would imagine you know but you could just use insulated plasterboard and just dot and dab it so no cold bridging effect

Yeah, that did cross my mind too...

 

[Hitch]

Dry above the line?

I'd pull the mastic and redo myself.

View attachment 374765

As its a bungalow, the top few inches is sheltered as it's right under the soffit.
Your red verticle line is an old mastic joint from a smaller conservatory, not a damp stain line.

Mortar fillet isn't a great colour match, so looks damper than it is.
Effectively the same as just the dampness where the same stone is inside and the other half inside.
The mastic line from frame to mortar fillet is absolutely fine on the outside.

 

[Dee J]

Ordinary plasterboard in a conservatory with or without existing damp issues is a bit dodgy. Moisture resistant board, ply, t&g timber or plastic cladding will all fare better when, not if, damp and mould strike.

 

[mike os]

If it’s damp you need to deal with the cause

Covering it will lead to future problems

 

[addjunkie]

Id dig that out, and the pointing away from the window and redo, with water-proffer in the mortar.

you could if you have the patience but and scribe a piece of upvc trim to the stone work sothe mortar is covered.

 

[dobbslc]

You could give the stone on the outside a coat of water repellant so it doesn't soak in and let capillary action draw it through into the house.

 

[Hitch]

you could if you have the patience but and scribe a piece of upvc trim to the stone work sothe mortar is covered.

I like that idea....


It's literally that one corner where the mortar looks slightly damp, same setup in the opposite corner, but rain doesn't drive into there any where near as much.

Perhaps put some tanking slurry on that section of the wall, back round to the patio door? (Right of the pic)

 

[brightspark]

if the mortars ok and the sealant . when its dry give it a coat of thompsons waterseal.ive had to do mine outside the windows

 

[gaz1]

if the mortars ok and the sealant . when its dry give it a coat of thompsons waterseal.ive had to do mine outside the windows

if its driving rain and all the seals look ok just use above

if the sealent has failed better off doing it now and reseal and then thompsons after that

 

[500e]

We had that problem rain smoking into concrete bricks, Thompson water seal 2 coats stopped itt

 

[Fazerruss]

The problem is possibly damp spreading to the inside wall when the outside is saturated. This is why buildings have cavities.
When an extension is correctly built on to the house then the wall it adjoins is cut in continue the cavity. This isolates the inside from the outside wall.
Problem with a conservatory is you don't have this so the inside wall next to the window is still connected to the outside wall so there is no barrier to stop moisture creeping in.

 

[gaz1]

its got no cavity as its a window butted up against the outsidewall

the silicone seals will have failed so windows that suffer blown wind and driving rain suffer from leaking silicone seals that need replacing every so often

the brick and stone most surfaces are pourous and flake off so that seal then breaks down and leaks over time stone is one of the worst for doing it

 

[500e]

Clean out the silicon seal as much as possible 2 coats of Thompson silicone water seal on that wall all of it not just a strip getting in to the joint then re seal the joint.
Note Do not get the sealer on the glass.
It will mark it permanently