Internal insulation and damp proofing

[slimsoul]

Hi,

Looking for some guidance on a kitchen renovation/damp proofing diy project, ......

as it stands:

A new chemical DPC has been injected, and high-level external floor levels lowered.
Walls hacked off and tanked.
The existing concrete floor was cut back sufficiently to expose the DPM and enable tanking below the floor level, as the DPM did not consistently reach the floor height (looked like it had been ripped in some areas).
I also applied liquid DPM in this area (rush of **** to the brain, I think, as the tanking already doing the same job. might regret this!)
Floor concreted back in.
I planned on tanking the joint between the floor and the wall, but may have created an issue with the liquid DPM???

I am now looking at creating a perimeter stud wall all round with Celotex insulation/vapour control/plasterboard. Did consider the insulated plasterboard, but with lots of fixing points/power points required in the room, decided on the stud option as i can also square/plumb things up. Happy to reconsider, though, if better options?

As far as the hacked off area of render, is it possible to fix Celotex over the tanking, bringing it out to the render depth rather than re-render?
This will all be hidden behind studs, so I thought it would be easier to foam adhesive the Celotex on.

Any help appreciated

 

[robinbanks]

Don't understand your question; you want to glue insulation onto a (becoming) cold wall, then leave a gap(cavity), then build an insulated stud wall. If the gap ends up with world air in it, what are you expecting the insulation glued to the cold wall to do?

If there will be no cavity, doesn't need to be a stud wall, just glue insulation all over the wall so it's flush/plumb then fix battens to the wall, through the insulation. This forms a void for you to run pipes and wires in and the battens help in keeping the insulation against the wall, then plasterboard over.
Note: vapour control barrier against the insulation, and try to avoid bashing holes in it when installing sockets (eg use 37 mm back boxes, 12.5mm plasterboard and 25mm battens)

Also please note the "your projects" forum is for blogging about what project you're doing, not asking questions- better to post queries like these in Building where they will be seen by more people

 

[slimsoul]

Hi Robin,

Sorry for the confusion! i think you have answered my question though.

In a nutshell, i was trying to make up the depth of the removed render and seal off the tanked area, probably an expensive method, thinking about it now.

Would you suggest re-rendering over the tanked area to make up the depth first (its about 25 - 40mm), so I will be glueing to a uniform surface?
I was under the impression exposed tanking might sweat, I am a novice though, so I might be talking ****

I have re-posted/clarified this in the Building forum, thanks for letting me know!

Thanks,

 

[robinbanks]

I wouldn't bother rerendering anything, just slice one of your insulation boards up into some thin strips and glue em to the wall to flush it off before you stick the sheets on. Once stuck in they'll stay in place while you fit a VCL (spray glue) then fix through it all with long screws through battens (put rawl plug on screw end before pushing through the insulation into the drilled hole

 

[slimsoul]

Thanks Robin, any suggestions for the adhesive for insulation to the wall, foam type?
I have some out-of-plumb walls up to 40mm in some areas. Will this be too deep for adhesives to dry properly

 

[robinbanks]

I use expanding foam, spray it in a \/\/\/\/\/\ pattern on the board, let it expand and go tacky (but not to the point it's skinned over and doesn't stick any more) then offer it up and press in place and wait a little/prop it with wood

It isn't going to be the final thing that holds everything, just for now

 

[ToolboxTalks]

You’ve done solid prep work already. Since the wall is tanked, you can fix Celotex over it with foam adhesive, just avoid puncturing the membrane. No need to re-render if it’ll be hidden. Leave a small air gap behind the insulation and put a vapour barrier on the warm side. Your plan for a stud wall makes sense for wiring and fixing points.

 

[slimsoul]

hoping it’s condensation…. but the tanked area where the jointing was repaired keeps showing surface moisture and looks darker than other areas. Tanking was done a month ago.

When bonding the boards to this is it a good idea to seal the perimeter of the board with foam adhesive so no moisture can get through, or is this all relying on the vapour barrier.