we are moving into an 18th century stone built house that now has signs of rising damp since the previous owner installed a damp proof concrete floor.

Under the concrete the original slate flagstones are still in place.

i am thinking i could solve the whole situation by just removing the concrete and going back to the flagstones. Is it possible to remove concrete in this way without smashing up the flagstones in the process?

If there was a damp proof membrane installed before the concrete there would be no damp now. Because you have damp now, you can assume that there is No dpc under the concrete and so it will probably of bonded to the flags.


If you remove the concrete it will not get rid of the rising damp.


What have you used to test for damp?

Have you tested the concrete and the walls?

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DIY | Donnas dream house

i am not sure you are following what i am saying.

originally:
damp flags. not damp walls

now:
dry waterproof concrete floor. damp walls.

I am not sure you are following what I am saying

If you remove the concrete it will not get rid of the rising damp.


What have you used to test for damp?

Have you tested the concrete and the walls?

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DIY | Donnas dream house

the surveyor tested both the walls and the floor.

the walls really didnt need testing though as the plaster is falling off up to about 9 inches above the skirting board.

I should add the wall in question was once (over 25 years ago) an external wall but is now an internal one.

the wall is also stone built rubble infill probably and about 2 foot thick. so i am guessing the only option is an electro osmotic dpc?

Yes, an electro osmosis DPC should sort it out.

I doubt that the concrete frloor has caused the damp walls though, they would probably still be damp without the concrete floor being there.

Is it just the one wall that is effected?

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DIY | Donnas dream house

attached is a floor plan with the wall in question circled in red.

two other walls are affected but not to the same extent.

I appreciate that removing the concrete might not fix the problem, but it did definitely cause it. as none of the walls were damp before it was installed. and they hadnt been damp for the last 20 years. (although we have only just bought the property we have known it for the last 20 years)

If it's just the one wall, I would be looking for a leak in the floor.

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the other walls are showing signs of damp, just not as bad as the circled wall.
possibly due to lack of radiator on that wall? there arent any pipes on that wall on either side or upstairs.....

I was thinking maybe in the kitchen floor

The problem with water is, if you stop it getting out it will go some place else.

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You say Could water be trickling down the inside from above, perhaps from the roof where the extension joins the old building?

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Mike

i did think of that, but the lead flashing that was put in place over the sloping roof does go very deep into the wall. and the guttering on the main roof above is sound. Also there is significantly less damp on the kitchen side of the wall. oh and all the pipes in the kitchen run above the floor as the floor was relaid in there at the same time as the dining room with the same concrete.

It's really unusual to get rising damp on just one wall, especially when it is an internal one

You don't think the house has had a damp proof course some years back and that one wall was missed do you?

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DIY | Donnas dream house

The old flag floor use to breathe or if you like let the damp out into the air, now its sealed the water is coming up the bricks.
If the concrete was laid on a Dpm then If you floor saw the concrete into sections almost through
then you would stand a good chance of breaking it up without breaking the flags once you have got a hole through it.

thats what i thought! lets hope they put a membrane down and didnt just use some sort of additive in the concrete.....