Vapor membrane for prefab concrete walls?

[julianf]

Ever ongoing garage -

Prefab concrete sections. Put together with mastic. But some of the joints still weep on the inside in heavy rain.

I'm about to batton and add 50mm cellotex.

What should I do prior?

I was considering sbr, but that's unlikely to be flawless.

So I guess some sort of vapor membrane behind the cellotex?

Walls will, eventually, be rendered externally (and, yes, I understand and accept that cracking may occur) which will limit ingress, but that's a job for about 3 years time...


So,

Sbr?
Membrane?

What's my best plan?

Thank you.

 

[mike os]

Probably best with a breathable membrane

 

[gaz1]

well id use 3x2 plastic blocks under a wood frame

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build4less.co.uk

whilst the wood frame is protected by the vapor barrior

however this may cause problems if you intend to hang stuff on the walls these blocks must be fitted under the uprights to support them

the base of these walls can be fitted with plastic skirting board so will give an air gap

the walls can also be fastened to the roof if you have also insulated or upgraded the roof

you can use the tanking method like this to plastic coat them first but thats up to you

https://www.mig-welding.co.uk/forum/threads/tanking-old-houses.102976/#post-1611350

 

[S-Rail]

I had this with mine . I bought some 100mm wide flashband , cut it into 50mm wide strips , stuck over all the joints then used a heat gun to melt the tar and pushed it on with a 2” chisel .

Also went around the base with 2 coats of bitumen , 50mm out and up , then allied a 100mm wide strip all the way round , again , used heat to massage the tar / bitumen on .

Hasn’t leaked since .

 

[brightspark]

caulk the leaking joints inside .you dont want any wet or dampness behind the membrane if possible it will only puddle on the floor behind and cause problems

 

[8ob]

I wouldn't bother with a membrane, pick a dry day caulk every nook and cranny and drown the internal walls/posts in sbr, let that dry and give everything a few coats of blackjack. Job done. no point in trying to hold back moisture in a cavity, way better to just stop water/moisture getting into it.

Bob