Damp concrete floor

23 Jun 2010
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United Kingdom
Hi i have an outbuilding that has a damp concrete floor, i know that my builder put dpm underneath the concrete but i think that something has gone wrong and i have told my builder to go due to some problems we have had. I have heard that he was supposed to do finishing on the surface but he has not. Can i just put surface dpm on the surface then put self leveling compound on top of that will that solve the dampness and is that the right way round.
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Could be residual moisture in concrete or just a poor DPC. Are the walls damp too. The danger of laying a DPM to the floor is that you will push the moisture into the walls. If the moisture is coming in from the walls then if you lay a DPM the moisture will still get to the flooring.
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The walls are not damp. i wanted to put liquid dpm on the floor not dpm the sheet. Do you think it would be ok. My walls have dpc and i have painted the internal bottom layer of engineering bricks with bitumen paint its about three bricks of engineering bricks high all around the building.
If the walls are OK then carry on and put a liquid DPM down. Make sure the floor is clean and dust free, apply the DPM (Iwould suggest a two coat application such as F Ball F75.) Allow it to cure and then apply a neoprene primer, P131 applied neat. Then apply the smoothing underlayment. Should be OK.

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