Damp around solid floor

31 Jul 2019
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United Kingdom
Hi i have a victorian terrace circa 1870. The back lounge in lower than front lounge and has a solid floor. The front lounge is over the cellar and wooden floor. I have bad a damp problem in back room since i bought house 5 years ago seemed to appear just after completion the damp patches are on chimney breast alcoves and bottom of chimney breast wall. Also on the internal wall between front and back room but only in this room not any damp in front?? I had a cowboy out 18 months ago who removed skirting and injected walls. Told me then plaster needed hacking off. I got someone else to do it and left it for 6 months before re plastered. All was ok for 3 months and now its as wet as ever. Called the cowboy many times over last year but keeps avoiding me and not turning up. The house next door is higher than my house and they insist they have no damp. Im at my wits end
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When the walls were re-plastered were they plastered down to ground level?
They should have stopped at the brickwork above where the holes were drilled. If they have gone to floor level they have bridged your new damp course. Only course of action is to remove any skirting and hack off the plaster to the correct height i.e. the bottom edge of the bricks above the damp course holes. Give the plaster above time to dry out then re-fit skirtings. Depending on height of dpc you may need to fit taller skirting boards.

Did he inject the walls before the plaster was hacked off? If so then he has done it wrong and probably not injected a damp proof solution at all. The plaster has to be hacked off up to 1 metre high and every brick along the lower course has to be injected until they are saturated with fluid. It is then allowed to dry out before re-plastering as above.
I was under the impression that injections just don't work.

Did anyone figure out the cause of the damp? Because that's the best way to sort it. Your chimney could have a few reasons can get a damp, some of them very simple to sort.

You probably have no damp in the front room because of the airflow underneath it with your cellar. I am though wondering too how well your solid floor was built, if it had damp proof membrane (or the membrane has failed) and that's the cause of some of the damp.

Our old Victorian terraced home (built around 1850) had an extension built, which was done on all the terraced properties in our row in the 60's (now the kitchen). We don't think the floor was done properly as we've damp only in the kitchen, the only solid floor part. It is worst on the wall that connects us to the neighbour who has the same extension. No DPC has been breached outside and we've air vents. Our neighbour had the injections done and didn't help the damp on her side of the wall either.
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STFF, you are right about a lot of slab floors not having a dpm, however, you and your neighbours damp may actually be being caused by your slab, not her injected dpc. Walls in Victorian houses, including party walls usually have solid walls 2 courses thick bonded to each other. This means damp in your property could be transferring to hers, from yours, above and below her dpc. Your damp being worse may also be because now her slab isn't penetrating into her walls as much then the excess is actually travelling into your walls instead.
Thanks Conny. I didn't say that her injected dpc was to blame, I just said it didn't help her side. We are both suffering damp equally too I think, talking to her.
We're still trying to get to the bottom of it, and will probably remove the floor and start again when we rip out the kitchen. It may not help, as I said because these extensions were built at the same time by the same council builders some years back so I should imagine it's the same problem next door. The worst damp is on the entire length of the joining wall which does make me think it has to be the solid floor(s) at fault.

Next door had a patio that was built over the DPC on her kitchen wall, and they had it removed a year ago because I wrote to the council (it's still a council property) and hopefully that will help matters, our newly installed drainage outside in the garden should help too. Sadly, even though this property is Victorian, the walls are unusually thin, something we realised shortly after we bought it and could hear the neighbours talking!
Thank you everyone for your replies. The cowboy damp contractor who won't come back and have a look at the problem did not hack the plaster off. He took all tbe skirts off and said he would come back in 6 months and re plaster. When i contacted him he gave me an extortionate price to re plaster so i went with a plasterer who was recommended. He said as the damp and salts were still coming through he didnt think it had worked and said the plaster should have been hacked of before injection. So rather me waste more money he hacked of and re plastered the alcove next to chimney breast which was the worst. It was for 3 months then its returned with a vengeance the damp on the internal wall backing onto my front lounge has also got worse and has now spread onto a wall that backs onto the hall. Thats the first time ive seen the damp there ill post some photos
This is the wall that backs onto my front lounge. You can see water mark. Ive drawn around it and its now spread onto wall on left if photo that backs onto my hall


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This wall is the alcove that is the left side of the chimney breast it is a party wall with next door and is at a right angle with that other wall. Next doors ground level is much higher than mine.


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These are all around the chimney breast. Ive just had a new roof 3 weeks ago and all new lead around chinmey and he filled any gaps between the two houses. But its got worse but we have had a lot of rain. I have also just had my back garden level reduced as it was much higher than the bouse hoping this would help.


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Have you got a water meter?

also please show us the soilpipes, rainwater pipes, drains and gullies around your house, and any manhole covers.

It is especially important to see any sunken, cracked or patched paving or concrete.

Also any paving or ground that is higher than the house or sloped towards it.

These points are because damp is water, and the water must be coming from somewhere. Find out the source of the water, and fix it, and the damp will stop.

In an old house, the drains and water pipes are probably leaking.
John, the OP said the damp was on an internal wall, and presumably because it's a Victorian terrace, she has neighbours either side of it. Would paving, drains, gullies etc outside effect that far in? She also said that she's lowered the garden, so paving shouldn't be higher.
Yes i have neighbours either side. But one side the level is much higher and this is the damp side
John, the OP said the damp was on an internal wall, and presumably because it's a Victorian terrace, she has neighbours either side of it. Would paving, drains, gullies etc outside effect that far in? She also said that she's lowered the garden, so paving shouldn't be higher.

That's true, but I bet the watermain does. They often run under the hall floor to the kitchen at the back.

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