Need advice on plastering penetrating damp

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My gable end needs externally rendering to stop penetrating damp, but this can't be done until spring time. In the meantime I need to re-plaster said wall internally due to a blown skim coat. I'd like to stop the penetrating damp coming through the wall until I can render it, how is best to do this?

Before the penetrating damp became such an issue I was just going to PVA the bonding then skim with multi finish, but am I now best to take it to the brick work and cover it with some sealer, anything recommended?

The wall is a double skin accrington brick construction for extra info, would it benefit from a lime 'breathable' finish?
 

zolco

Private Member
My gable end needs externally rendering to stop penetrating damp, but this can't be done until spring time. In the meantime I need to re-plaster said wall internally due to a blown skim coat. I'd like to stop the penetrating damp coming through the wall until I can render it, how is best to do this?

Before the penetrating damp became such an issue I was just going to PVA the bonding then skim with multi finish, but am I now best to take it to the brick work and cover it with some sealer, anything recommended?

The wall is a double skin accrington brick construction for extra info, would it benefit from a lime 'breathable' finish?
Safeguard stormguard might work
 

robbiboy1970

Active Member
back to brick......then sika uk.(check them out)...i know of a dude who painted on acrypol roof seal then dot & dab and skim
 
Just repoint the gable and use a good stone/brick sealer
https://www.kingfisheruk.com/extreme_climate_-_next_generation_water_seal-item-26ec
this is what we use to seal mono
I can't repoint and after spending 2.5k on a conventional dpc because I was told this would fix the damp I also can't afford to pay someone right now.

Do you have any idea how the damp is bridging the cavity to come through the internal skin? I've had the cavity cleared of 'snots' etc, the only thing I can think is the brick ties.
 

paddy5

Active Member
If the bonding is saturated am surprised it did not blow just as the skim, if the bonding saturated how will you skim over, presume cavity was scoped, strange to have cavity wall without dpc, are you below external ground level.

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He is taking the piss what did the damp firm do for 2.5k? and why aren't they fixing the problem?
They took out two rows of bricks along the dpc line from the inside wall along the gable and front wall, placed a piece of dpc membrane under the new bricks, fitted weep holes and a top piece of dpc. They also pointed the corners of the gable wall and chimney benching. My research suggested this was standard price for a conventional dpc rather than injected.

They are not fixing it as they said it needs repointing, nothing to do with the dpc they installed.
 
If the bonding is saturated am surprised it did not blow just as the skim, if the bonding saturated how will you skim over, presume cavity was scoped, strange to have cavity wall without dpc, are you below external ground level.

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No bonding has blown yet somehow.

Cavity wall has been scooped when new internal dpc was installed, no we are not below ground level. It does seem to be coming through the pointing on the external wall, no idea how it is bridging the cavity to the internal though now that the cavity is now cleared.
 

paddy5

Active Member
Could you batten and felt temporarily till which time the external can be finished, how long ago for dpc? could be residual, dehumidifier? If bonding saturated skimming is a no no.

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Could you batten and felt temporarily till which time the external can be finished, how long ago for dpc? could be residual, dehumidifier? If bonding saturated skimming is a no no.

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I could, but ideally like to just do it once.

dpc is roughly 8 weeks old now, it is definitely tracking rather than rising. Every time it rained we had a pool of water under a window (inside), I resealed the external frame last weekend, next time it rained there was no pool, but the internal wall next to the window was soaked.
 
So what did they do for the £2.5k?
They fitted a conventional dpc rather than an injected one which consists of:

Taking out two rows of bricks along the dpc line from the inside wall along the gable and front wall, placed a piece of dpc membrane under the new bricks, fitted weep holes and a top piece of dpc. They also pointed the corners of the gable wall and chimney benching.
 

flynnyman

Well-Known Member
So what did they do for the £2.5k?
Just seen your other posts and yes you have been scammed they took out a perfect damp course and replaced with another. What was the problem in the first place and was it visible? get some pics up and also when you mention bonding are you on about carlite bonding plaster?
 
Just seen your other posts and yes you have been scammed they took out a perfect damp course and replaced with another. What was the problem in the first place and was it visible? get some pics up and also when you mention bonding are you on about carlite bonding plaster?
The said the existing dpc had failed.

The original problem was we had damp coming in the front corner, above the dpc line, it looked like tracking damp from blocked cavities. We also had rotted joists ends along the front end of the house and water coming through the chimney breast from a hole in the benching.

They ran a damp meter along the external walls and the reading was high, they said we would need a new conventional dpc along the external wall as they wouldn't guarantee an injection one. Said they also needed to repoint the corners of the gabel end and would investigate the chimney.

When they where fitting the dpc they said they had to take out 2 rows of brick as the cavity was so blocked, they also said the cavity was dripping with water from the external wall which is why they installed weep holes in to the sub floor.

They fixed the chimney but to be honest, the other damp is worse than it was before they started, it still breaches the dpc line but now does it in 4-5 places rather than 2.

They also replaced the rotted joist ends.

And yes I was referring to carlite, unless there is a better product to use for the damp issues.

I have uploaded a picture showing the front of the house, you can see the replaced joist ends and the grey bricks are the new ones fitted, the red parts are the weep holes. Behind the electrical box is where most of the damp was, and still is, they have also repointed the corner of that external wall.

IMG_4009.JPG
 
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flynnyman

Well-Known Member
Did you see the cavity blocked and how did they know?weep holes is a first especially without a cavity tray. The damp metre will always show damp especially outside and the last thing you should be using is gupsum based backing plasters on a damp job.
 
Did you see the cavity blocked and how did they know?weep holes is a first especially without a cavity tray. The damp metre will always show damp especially outside and the last thing you should be using is gupsum based backing plasters on a damp job.
My partner saw them removing the debris from the cavity. How did they know what sorry?

The metre was used on the internal not the external wall, sorry if that wasn't clear. They have put a cavity tray in by the weep holes.
 

flynnyman

Well-Known Member
How did they know the cavity was blocked? And the metre will always show damp it's a con for what the are using it for. The weep holes should be on the outside not the inside (or am I seeing things?). Who patched up with bonding and where?
 
How did they know the cavity was blocked? And the metre will always show damp it's a con for what the are using it for. The weep holes should be on the outside not the inside (or am I seeing things?). Who patched up with bonding and where?
They didn't know, I suspected before I asked them round to investigate. They confirmed it was blocked when they removed the bricks in the corner to place dpc. They have put the weep holes on the inside I assume because thats where they had already removed bricks.

No one has patched up with bonding yet.
 

keithuk

Private Member
How did they know the cavity was blocked? And the metre will always show damp it's a con for what the are using it for. The weep holes should be on the outside not the inside (or am I seeing things?). Who patched up with bonding and where?
we use to clean out loads of cavitys back in the day
 

Arti

Well-Known Member
Its rare to see a failed physical dpc. Blocked cavities are very common. Do you have airbricks to ventilate the cavity and sub floor?

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