Our victorian terrace has a history of damp problems. The previous
owners had a standard injection/render/skim treatment to rectify
this. The thing is - in a fit of rage and stupidity when trying to
free up a radiator tailpipe that had got stuck - I broke away a fist-
sized chunk of inch-thick render where the pipe passes through the
wall. Once I'd got the radiator sorted, I simply plastered in the
broken area. The problem - as you may have guessed - is that the
plastered-in section has since become extremely damp to the touch and
smell. I'm sure the water isn't from the radiator; the rest of the
surrounding area is dry and the water pressure is stable (if a little
high). We have put a lot of time and effort into this house, so am
now having hysterical visions of all moisture migrating to this one
spot once we finally decorate the place!

So, before I do anything else reckless, I thought I'd consult the
collected wisdom here for a solution. Would some kind of paint-on
barrier do the job of the broken render and protect the surface
plaster? Or should I replace the render? If the latter, what exactly
is it made of?

dangemrod wrote:
Our victorian terrace has a history of damp problems. The previous
owners had a standard injection/render/skim treatment to rectify
this. The thing is - in a fit of rage and stupidity when trying to
free up a radiator tailpipe that had got stuck - I broke away a fist-
sized chunk of inch-thick render where the pipe passes through the
wall. Once I'd got the radiator sorted, I simply plastered in the
broken area. The problem - as you may have guessed - is that the
plastered-in section has since become extremely damp to the touch and
smell. I'm sure the water isn't from the radiator;

I think I'd want to verify this by knocking out the new plaster.
"Extremely damp" sounds like a leak


the rest of the
surrounding area is dry and the water pressure is stable (if a little
high). We have put a lot of time and effort into this house, so am
now having hysterical visions of all moisture migrating to this one
spot once we finally decorate the place!

So, before I do anything else reckless, I thought I'd consult the
collected wisdom here for a solution. Would some kind of paint-on
barrier do the job of the broken render and protect the surface
plaster? Or should I replace the render? If the latter, what exactly
is it made of?

In article ,
Stuart Noble writes:
dangemrod wrote:
Our victorian terrace has a history of damp problems. The previous
owners had a standard injection/render/skim treatment to rectify
this. The thing is - in a fit of rage and stupidity when trying to
free up a radiator tailpipe that had got stuck - I broke away a fist-
sized chunk of inch-thick render where the pipe passes through the
wall. Once I'd got the radiator sorted, I simply plastered in the
broken area. The problem - as you may have guessed - is that the
plastered-in section has since become extremely damp to the touch and
smell. I'm sure the water isn't from the radiator;

I think I'd want to verify this by knocking out the new plaster.
"Extremely damp" sounds like a leak

I'd agree.

the rest of the
surrounding area is dry and the water pressure is stable (if a little
high). We have put a lot of time and effort into this house, so am
now having hysterical visions of all moisture migrating to this one
spot once we finally decorate the place!

So, before I do anything else reckless, I thought I'd consult the
collected wisdom here for a solution. Would some kind of paint-on
barrier do the job of the broken render and protect the surface
plaster? Or should I replace the render? If the latter, what exactly
is it made of?

Gypsom plaster will wick moisture through, so you'll have to
remove what you put in. If it's been wet for a while, that should
be easy.

Do you know if the wall was internally tanked to prevent moisture
coming through? This might be the case if it's below ground level.
If so, it will need the tanking properly repaired.

If not, then use a sand/cement and waterproofer scratch (under)
coat, and then you can apply gypsom plaster finish coat on top.
Wrap the copper pipe to protect it from the cement.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 30 Jul, 15:20, dangemrod wrote:
Our victorian terrace has a history of damp problems. The previous
owners had a standard injection/render/skim treatment to rectify
this. The thing is - in a fit of rage and stupidity when trying to
free up a radiator tailpipe that had got stuck - I broke away a fist-
sized chunk of inch-thick render where the pipe passes through the
wall. Once I'd got the radiator sorted, I simply plastered in the
broken area. The problem - as you may have guessed - is that the
plastered-in section has since become extremely damp to the touch and
smell. I'm sure the water isn't from the radiator; the rest of the
surrounding area is dry and the water pressure is stable (if a little
high). We have put a lot of time and effort into this house, so am
now having hysterical visions of all moisture migrating to this one
spot once we finally decorate the place!

So, before I do anything else reckless, I thought I'd consult the
collected wisdom here for a solution. Would some kind of paint-on
barrier do the job of the broken render and protect the surface
plaster? Or should I replace the render? If the latter, what exactly
is it made of?
Dear Dangemrod

Penny to the pound you have not put back in render to the dpc spec but
have put in a gypsum-based material which has allowed the hygroscopic
salts present in the brickwork to permeate through to the finish
plaster
cure is to remove all traces of said plaster
hack out more render such that it is excavated like a dental filling
with a greater area of removal adjacent to the wall than visible hole
on the surface
this can be done in a moment or two with an suitable angle grinder
roughen up the surface by keying brick and disc cut render
apply coat of SBR bonding additive and whilst still wet a spatter coat
of 3:1 sand cement render 12 mm thick containg glue (sbr) and SIKA No
1
Let is set but not dry
apply further coats of same till 2 mm left and finish off with multi
finish
if fussy remove 25mm of finish on old plaster to spread joins and
minimise cracking
Chris

On 30 Jul, 15:20, dangemrod wrote:
Our victorian terrace has a history of damp problems. The previous
owners had a standard injection/render/skim treatment to rectify
this. The thing is - in a fit of rage and stupidity when trying to
free up a radiator tailpipe that had got stuck - I broke away a fist-
sized chunk of inch-thick render where the pipe passes through the
wall. Once I'd got the radiator sorted, I simply plastered in the
broken area. The problem - as you may have guessed - is that the
plastered-in section has since become extremely damp to the touch and
smell. I'm sure the water isn't from the radiator; the rest of the
surrounding area is dry and the water pressure is stable (if a little
high). We have put a lot of time and effort into this house, so am
now having hysterical visions of all moisture migrating to this one
spot once we finally decorate the place!

So, before I do anything else reckless, I thought I'd consult the
collected wisdom here for a solution. Would some kind of paint-on
barrier do the job of the broken render and protect the surface
plaster? Or should I replace the render? If the latter, what exactly
is it made of?

Better ask the folk with the subject knowledge on the pp forum:
http://periodpropertyshop.co.uk/phpB...wforum.php?f=1


NT