Cracks in concrete under carpet

Street · 6 Apr 2017 at 22:24

In preparation for our new carpet being fitted next week, I started pulling the old laminate up tonight. I got towards the middle of the room and noticed there was a damp patch underneath and the underlay was damp.

There used to be a separating wall across the room and this has been removed and it appears it is the concrete under this that has cracked and is letting damp up into the room. The rest of the floor seems OK apart from a few bits around the edge but these don't appear damp.

Does this look like a big job to sort? It looks like I'm going to have to delay getting the carpet fitted next week as obviously this can't go down on damp floor. Bit of a pain as I thought I was finally going to get the living room sorted after a year, the carpet was the last thing to do!

LOAM · 6 Apr 2017 at 22:42

Is that an asphalt floor covering?

Street · 6 Apr 2017 at 22:56

It's not asphalt, not entirely sure what it is though. It may be some sort of levelling compound.

LOAM · 6 Apr 2017 at 22:57

With it being black it looks like a hot applied tanking.

Street · 6 Apr 2017 at 23:21

Ah possibly, it all seems in good condition apart from the edges, but there's no damp around these bits. Just the cracked concrete in the middle.

a1ex2001 · 7 Apr 2017 at 07:19

I suspect there is no damp proof course in the wall that's been romoved so you probably have damp rising up it. Call a few general builders to have a look you may get lucky and just need some tanking over the top or it could be a leaky heating pipe etc

dark-knight · 7 Apr 2017 at 08:07

The first image looks as though there was a supporting wall there at one point and someone has crudely filled in the difference in height etc with poor concrete/screed. The second image also looks as though the cement has cracked maybe through age or poor application (unsure how old the house is). Id sweep up and chip out all the loose parts and give it an hoover, have a good look and possibly as mentioned get a general builder to look it over.

Mel_P · 7 Apr 2017 at 08:23

If it was an old solid wall without a damp course that was removed you may have to dig out all loose stuff and put some membrane down over the "join". The concrete "filler" would have cracked with the movement of the wooden floor as people walked over it.

Street · 7 Apr 2017 at 09:44

Yeh, it was an old wall running between two rooms that has been removed by the previous owners. It's a 1930s house but the previous owners were elderly and had been there for about 40 years I think, they'd bodged just about everything or had it done on the cheap so what I found doesn't surprise me. I was hoping I could do it myself and just pour some concrete or something in, but it's probably worth getting someone in who knows what they're doing if it's damp! It's been one thing after another with this house, really annoyed with it just when I thought I was getting somewhere and all the big jobs were done!

dark-knight · 7 Apr 2017 at 12:02

Street said:
Yeh, it was an old wall running between two rooms that has been removed by the previous owners. It's a 1930s house but the previous owners were elderly and had been there for about 40 years I think, they'd bodged just about everything or had it done on the cheap so what I found doesn't surprise me. I was hoping I could do it myself and just pour some concrete or something in, but it's probably worth getting someone in who knows what they're doing if it's damp! It's been one thing after another with this house, really annoyed with it just when I thought I was getting somewhere and all the big jobs were done!

Its an oldish house these things happen, solidly built though in comparison to the new builds.

Street · 7 Apr 2017 at 17:03

Spoke to a couple builders today and they just said to do it myself. All they would do is chip it out, put some Visqueen down then concrete over the top, two different people said the same thing so might give it a crack!