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UGH! Horrible damp block of hearth concrete

Postby missus_miggins » Tue Apr 15, 2008 12:38 am

My new place has a horrible block of damp concrete at the hearth where "they" tore the 1870s fireplace out at some point in the 20th century. Yuk.

I want to remove the top two-and-a-half inches of this stuff (with a chisel, it's soft as cheese and breaking off all over the place as is) put down another (? I doubt it) damp membrane and then lay new floorboards to take the floor up to the wall. Rather than having a hideous blob of manky cemont as a talking point in my front room.

Just want to know if this is a good idea or a bad one, as I have never attempted it before. I'm reasonably practical and competant at projects but am feeling a bit wary. Who knows what lurks beneath? I have opened up old fireplaces to find ghastly nests of dead birds before......

My ideal end of project is having a lovely wooden floor without grim damp concrete blobby thing festering. Should I just go for it? Are thre any pit-falls I should look out for? All help appreciated.
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Simply Build It

Postby rosebery » Sat Apr 19, 2008 11:26 am

You'll probably find you can remove a lot more than 2 1/2 inches and it'll probably be as soft as cheese all the way down.

The reason it's damp is that it's bridging the damp course. Dig it all out below the DPC level and leave the void in place.

Fit appropriate joisting over the hole to take your new boards.

Neither you nor I know what lurks beneath!! Go on - go for it. You're not doing anything structural.

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