IWI on wallpaper

[NandM]

So we finally managed to complete on our purchase and get our keys a couple of weeks ago. I plan on IWI but am wodering if it's OK to leave the old wallpaper in place if there's no sign of damp and the plaster sounds OK.

 

I'm planning on using adhesive to fix the first layer of insulation to the wall. These will then have additional support via a stud wall pressed up tightly against it (no screws into wall), and by additional insulation in the frame.

 

 

[jayc89]

What's on the external face of the wall? Render etc?

I guess you're going for the "warm batten" method - the idea of the insulation taped tight against the wall is to form an impervious barrier. If there was ever any moisture build up behind the insulation, you'll end up with mould on that wallpaper and no access to it.

 

I'd be inclined to knock it all off it back to brick and gain a few cm extra in the process.

[NandM]

Thanks Jay. It's a cavity wall (brick - cavity - brick) which isn't currently filled. I may get it filled depending on what quotes I get.

 

There's only a around 1CM of plaster on the wall - so not alot of of space to gain. Going back to brick would be easier than stripping the paper....but only if needs to be stripped.

 

** Edit **  - looks like the paper needs to come off...so might aswell remove the plaster. https://www.kingspan.com/gb/en-gb/products/insulation-boards/insulation-technical-hub/articles-and-advice/can-you-fix-insulated-plasterboard-to-existing-pla

Edited October 28, 2021 by NandM

[PeterW]

I would start with cavity wall insulation - blown bead isn’t expensive and is a days job for a decent company. I can recommend a couple depending on where you are in the U.K.  

 

Then I would look at air tightness, windows and doors and finding the leaks. 
 

Finally, look at improving internal insulation but only when you’ve done the first two. 
 

What insulation is in the attic and the floor..? 

[NandM]

I'm in Brum - so recommendations would be great.

 

It looks like the cavities (50mm) at the front and rear have been filled as I can see the mortar for the holes - but I need to check the side again as it looks like it wasn't done. Also - I don't have details on what was done in the filled cavities or when. It's an empty house but I'd like to get this (and some more) done in the next 4-5 months so we can move in.

 

Yes, air tightness is on my list, but wanted to get the walls out of the way first....or does it make more sense to do air tightness first??

 

Windows and doors will be upgraded once in two phases as I'm planning on some fairly extensive work in the summer.

 

The 1950's floor is concrete with a screed, wooden blocks, timber boards and more fancy timber strip on top. I have around 80mm to current floor height, so will be getting 70mm insulation down and laying a floating engineered floor (18ish mm) on top. 

 

The attic also needs insulating above what's currently there - but it's boarded so hard to tell. I'd probably leave this until last as doing the others first would mean we can move in.

 

 

[NandM]

I took the plaster off one part of the wall and found it easy to fall off and almost sand like.

 

I'm guessing the plaster throughout the house may be like this. I'll drill some pilot holes and see how it behaves, but if it is that crumbly, does it make sense to take it all off? The main reason is that it could cause some headaches when fixing into the walls.

[markc]

3 hours ago, NandM said:

I took the plaster off one part of the wall and found it easy to fall off and almost sand like.

 

I'm guessing the plaster throughout the house may be like this. I'll drill some pilot holes and see how it behaves, but if it is that crumbly, does it make sense to take it all off? The main reason is that it could cause some headaches when fixing into the walls.

Once plaster starts to crumble and come away from the wall easily it’s time to remove it.

ppl  get them skimmed over but they sound hollow if bumped and often fall off anyway.

[NandM]

Thought so...at least its easier than removing wallpaper!