Need help

[lee2012]

Hi, I've recently done a job where there was damp patches on the external walls. I hacked back the old lime plaster left 7 days to dry out.
Then applied a strong water proof scratch coat to walls. Followed by 25 mm cellotex then dot and dab moisture board. Then a skim.
2 weeks later there is a 50 mm damp patch in the middle of the wall.
Any advise would be appreciated!!!!

 

[brimplas1]

You dot and dabbed onto the cellotex???

 

[brimplas1]

You would have been better studding it to create a cavity..... breathable membrane on the back, insulate the stud and vapour barrier on the front then board and skim...... This is how regs advise it be done..

 

[lee2012]

I foamed the cellotex to plasterboard then stuck with adhesive. I thought the cellotex would act as a vapour barrier as its foil back. All other rooms are fine just this one spot.
Don't understand why. Next room I will try your method thanks.

 

[kgreigh]

That damp patch would be the least of my worries,I'm not convinced that the board adhesive will hold the weight of the celotex,board and skim for very long,it is likely to fail at the celotex/adhesive bond.

 

[kgreigh]

I know you've skimmed it now but could you put some secondary fixings at or below skirting board level?its not much but at least it's something.

 

[beddy]

Id hate to see this room in 10 years

 

[roryston]

You should of.studded in front of the wall.

The celotex probably got a break in it somewhere and the foam.inside is acting as a sponge

 

[zolco]

You have to mechanically fix insulated plasterboards when you dab them due to fire regs isn't it?

 

[beddy]

Yes. And sticking celotex boards to the wall with board adhesive? And putting a sand and cement scratch on instead of lime?

 

[lee2012]

There is a few fixing in each board so boards going no where.
I couldn't stud wall as involved moving door ways and pipe work.and customer didn't want this. It's only 3 boards do might start again cheers for input.
All taking in thanks