chemical damp proofing

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Need to install a chemical damp course. Old house, solid brick walls, no D.P.C.
Seem to be lots of products ( all claiming to be the best ) on the market.
Would appreciate any feedback on what's good and what's not
 
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why do you need a DPC?
do you mean injected chemicals?
is the house rendered?
is it a solid floor? is the ground level lower than the FFL?
can you post pics of inside an outside?please show any damp signs.
 
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Thanks for your reply
yes I meant injected chemicals
House isn't rendered.
Not a solid floor. joists and floorboards
Ground level is lower that the FFL
The damp is coming up on an internal wall from the earth floor under the floorboards
 
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is the damp showin on both sides of the internal wall?
does, or did, this wall have a chimney breast on it?
have you looked below the suspended floor?
are ther enough air bricks givin through ventilation under the floor?
 
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The damp only shows on one side of the wall. the other side is bare brick.
There has never been a chimney breast on the wall
There are 2 airbricks both of which are clear, one on the front elevation, one on the side
The earth under the suspended floor feels dry to the touch
 
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thanks for answerin my questions - pics would still be handy.

moisture on the bare brick side of the wall might be evaporatin - any signs of white salts?
the plaster on the other side will hold the salts an these salts maybe attract condensation.

without pics i can only suggest, i dont have much faith in DPC chemicals so i'd advise you hack off the plaster to about 300mm above damp stains an render in a 3:1 sand an lime mix with a remedial skim.

air bricks should be 2m min centres around the buildin except for solid floors.
 
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Thanks again for your replies. Will post some pictures over the weekend. We did have a chemical DPC installed on the external walls about 7 years ago and that did resolve a similar problem we were having on those walls
 
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when they installed a chemical DPC 7 years ago did they also nock off an re-plaster/render?
 
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We had the same, poor sub floor ventilation, line mortar, narrow void and old slate dpc on single brick wall allowing some moisture by, and no where for it to evaporate. We just bought a couple of tubes of cream from Wickes, dry zone or something, and injected it. Also improved the ventilation. And tried to reduce the dampness under the floor in general.
It seems to be drying out quicker than it gets wet now, which was the aim.
 
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Pics as requested. The damp rises about 150mm but no higher. The wall was replastered 7 years ago but at that time there was no sign of damp on the wall.First noticed it 2-3 years ago. Wasn't sure it was damp at first, so used stain-blocker on it.
IMG_20181103_132539.jpg
IMG_20181103_132528.jpg
IMG_20181103_132518.jpg
IMG_20181103_132510.jpg
 
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some confusion here. my question in post #8 was about the outside walls that were DPC'ed 7yrs ago. were they hacked off an rendered at that time?

the pics presumably show the inside wall - was that inside wall also hacked off an rendered 7yrs ago?

your joists will be seated in pockets in that wall an might be rottin - a couple of boards have been renewed in the past.
the joist tails on the other side of the wall might also be seated in pockets in the wall an likewise rottin.
you need to examine an probe all the joist tails in the wall.
 
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some confusion here. my question in post #8 was about the outside walls that were DPC'ed 7yrs ago. were they hacked off an rendered at that time?

the pics presumably show the inside wall - was that inside wall also hacked off an rendered 7yrs ago?

your joists will be seated in pockets in that wall an might be rottin - a couple of boards have been renewed in the past.
the joist tails on the other side of the wall might also be seated in pockets in the wall an likewise rottin.
you need to examine an probe all the joist tails in the wall.

Hi Bodasd. Is it normal to hack off internal plaster and then render in the case of rising damp? I thought it was only necessary in the case of dry rot.
 
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opps, yes its always done for rising or penetrating damp because the salt in the plaster will continue to attract moisture from the masonry and condensation fron the air.
 
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opps, yes its always done for rising or penetrating damp because the salt in the plaster will continue to attract moisture from the masonry and condensation fron the air.

That makes sense, thanks.
 
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Yes. The pics are of the inside wall. The outside wall were all hacked off to 1 metre above FFL rendered then replastered. The inside walls were replastered only as at that time they showed no signs of damp. The floorboards are all original. Have checked the joists under the floor and the exposed joist tails in the cellar. They feel dry but am going to invest in a moisture meter. Thanks again for all your advice
 

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