How to resolve damp patch

[frediaz]

Hello,

I have a damp patch that does not seem to want to go. It has mould growing on it.
The builders who worked on it put a thick layer of it and painted on it before it was fully dry but that was months ago.
I do not think it is rising damp as the wall on the other side does not have the damp patch and there was no rising damp at the time that the plastering was carried out.
It cannot be coming from a roof joint above as the patch is at the bottom of the wall.
And it is an internal wall too! but there was broken gutter in the corner above.

I told the decorators to apply a damp barrier spray before painting. They said they did but the wall is still damaged. Now the plaster is irregular.

Can people advise what to do? See photos.

Thanks

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• frediaz
• 13 Feb 2014
• 1

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• frediaz
• 13 Feb 2014
• 1

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• frediaz
• 13 Feb 2014
• 1

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• frediaz
• 13 Feb 2014
• 1

 

[skhudy]

The other side of that wall is a bathroom. Are you sure nothing is leaking on the other side? No pipes buried in the floor? (i had one which was leaking embeded in concrete and it ruined the plaster on a wall a meter away. Black mould needs constant moisture i believe

this might be interesting to read?
http://www.ehow.co.uk/info_8170906_black-mold-grow-plaster-walls.html

 

[gg77]

As skhudy says, I'd check for service pipes or something. We had a similar problem in our uncle's kitchen. It turned out that the dishwasher had sprung a leak behind the skirting and had been dripping away for months. It looked exactly the same as this, but because it was about 4 cabinets away in the kitchen it didn't get noticed for a while. Once it was fully investigated, there was moisture everywhere but it was all hidden away.

what's behind that boxing in to the left in the 4th picture? Is there any way you can take it off and have a look?

 

[frediaz]

Thanks so far, there are no pipes near the wall, really. The box to the left is just to contain the pipes that feed the basin a bit further to the left so they are about 1/5 meter away from the wall but if they were leaking they would damage the wall on the same side first.

Supposing the damp is being carries sideways from the brick wall outside, which does not make contact with the internal bathroom wall but it touches the conservatory wall with the damp patch. There has been water constantly falling in that corner of the brick wall against the conservatory as there was not downpipe.

I guess it is necessary to remove a layer of the plaster to get rid of the black mould. And skim it again.

 

[ree]

Did you have a knock-through above that wall when the conservatory was built?

Can you clear the items from the outside corner, and post pics of that area from ground level up to the roof?

The builders referred to, are they responsible for any conservatory or knock through work?

 

[skhudy]

Thanks so far, there are no pipes near the wall, really. The box to the left is just to contain the pipes that feed the basin a bit further to the left so they are about 1/5 meter away from the wall but if they were leaking they would damage the wall on the same side first.

It depends on how the damp proof has been put in. for example there could be a leak further up from a service / waste pipe *below* the dpc so prevent the damp showing up on plaster on the external wall, but the water is finding a path underneath the tiles to and up that internal wall.

can you not inspect under the boxing?

To get rid of the mould, once dry spray diluted bleech, and I *think* you could just rub down pva and skim.

 

[frediaz]

Yes we cut a hole in the wall for the conservatory. I am starting to believe that water from the gutter with no downpipe above has got through the corner of the brick wall and the conservatory into the wall inside.

Here are the photos:

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• frediaz
• 13 Feb 2014
• 1

Outside corner:
I used to put the bucket in the corner above the gully, to catch the water from the gutter, but the stupid builders removed it while not putting the downpipe.

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• frediaz
• 13 Feb 2014
• 1

Wall when it was plastered but a long time ago, and then painted while still wet:

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• frediaz
• 13 Feb 2014
• 1

 

[frediaz]

I have hired and fired a number of builders on this job so it will be difficult to pin down any of them on the blame. They will all blame each other.

 

[roy c]

...Yes we cut a hole in the wall for the conservatory. I am starting to believe that water from the gutter with no downpipe above has got through the corner of the brick wall and the conservatory into the wall inside.--------I think you have probably found the problem yourself The way the gulley is situated is too far away from the wall and should have a surround around it. Then the gutter pipe could be held on the wall with brackets and the shoe could be kicked out to go in the gulley. Also the pipe coming out of the wall should also go into the gulley. It looks like they have connected on to the sewer pipe some how!!! Instead.. I wouldn't be surprised if you dug the gulley up and exposed the pipe work you might find a leak!! If you go down that route put some pics up and let us lot have a look at them.

 

[frediaz]

Roy,

No the connections to the gulley are right, the pipe coming from the sink goes into the gully, then the gully goes into the sewer pipe. The local BC inspector has checked this. of course the problem is that the downpipe from the gutter is still not there. I may have to go and install it myself because the current bad weather is not helping.

 

[ree]

The lack of a downpipe seems to be the issue. Dont wait, get out there and clip a length of pipe up.

And carefully examine the vertical join where the conservatory butts up to the brickwork.

Perhaps stand on a ladder or steps, and examine the tile roof junction with the con. roof - look for possibilities of water entering from above. Maybe pic it.

The knock through that i was referring to is probably irrelevant now that i can see the rough footprint of the conservatory.
I was looking for an external cavity wall that was weeping into a single skin interior wall (the damaged wall).
The damaged wall, i assume, is a cavity wall?

The job looks a little rough and if you want more suggestions then come back here if you think its worthwhile.

 

[roy c]

I personally would do away with the gravel around the gulley and pipe and water proof all the wall around that area and concrete the whole lot with the falls running away from the house. And reposition the gulley nearer to the wall and have a surround coming out from the wall and the down spout from the connie going into it.What sub-base is under the gravel ?lt looks like all water falling in that area could track back into the area that is showing damp if there is not a working dpc.lt would be good to see a pic with all the gravel around the gulley removed.

 

[frediaz]

I find it difficult to believe that water is being soaked up by the walll from the gully area as the wall nearer to the gully has no damage.
The damaged wall is not cavity as it was an internal door. I doubt about rding damp as it was not there when we installed the conservatory. The DPC seems to be OK and the conservatory is suspended.

I still need gto go up and check the joint in the roof.

 

[ree]

edited out

 

[ree]

"The damaged wall is not cavity as it was an internal door."
Which is how i originally identified it but, given the conservatory footprint from the pics, i'm puzzled by what the original plan view of that part of your house was?

Could you scan a quick plan view drawing of the rear walls before the conservatory was built?

The wall to the right in pic one: how does the main house roof come down to meet it?

The "window" opening to the left in pic three is surely in the original external cavity wall?