Buckled concrete floor

[MrFitz]

Hi all, I'm in the process of buying a new terraced house which is on a steep hill and has 2 reception room. The floor in both of the reception rooms have huge lumps in. I've had 2 builders come and give me their opinion which are different and am wondering which is right.

The first one says its gas from old mining shafts and the whole of the 2 rooms needs to be dug out, dig down 18", a layer of membrane and re concreted at a cost of £3k
The second says I only need to dig out the actual hump in the floor and lay new concrete.

Any help would be much appreciated, thanks!

 

[footprints]

Lots of industrial areas used waste for rubble infill often using the generic name "Red Ash" take a look at this site lots of information on the net about it, try your local council they may be able to advise if it is a problem in their area.

http://www.psdflooring.co.uk/sulfate.html

 

[ree]

Why not post pics of the floors?

Are the "lumps" continuous from room to room or entirely separate?

Does the hillside slope run back to front of the house or down the terrace?

Is the house located in a mining area?

The gas theory sounds off the wall but any mention of gas should have you making enquiries about radon - ask the neighbours and the council for radon info.

 

[MrFitz]

Thanks footprints, I'll get in touch with the council.

Apparently there is a lot of old mines in the area, is there a site I can double check this? He said gas/minerals coming up from the mines that has caused the lumps. They are 2 seperate lumps, one in each reception room. Thanks guys

 

[MrFitz]

The hill is down the terraced too.

 

[^woody^]

If it's in an area prone to sulphate attack of the floors, you may not get a mortgage advance.

It's also normally associated with a drain problem.

Search the posts here, it's been covered extensively.

 

[MrFitz]

Thank, woody. I read through a lot of your posts and found it very helpful. The house was built in 1920 so hopefully its not prone to a sulphate attack.