sub-floor needs replacing

Beverley

On lifting the carpet in my ex local authority house, I found lumps, bumps and cracks running the length and breadth of my living room. The local authority tell me this is called floor heave - they are not liable for it and my insurance does not cover it either.

I've had 3 builders take a look at it and all have said that it is caused by a chemical reaction between the ashes that were used as hardcore, and the concrete laid on top - and that the only sensible remedy is to dig it out and replace it. 2 said they'd need to go down by 2 feet and the other by a foot.

I got a written quote from A of £1750 (inc VAT). He said that he would dig down 12", remove all rubble, replace the hardcore, and cover in concrete. I asked how it would prevent damp from rising up thorugh the floor and he asked me what kind of waterproof layer he shouold get and seemed to not really know what he was talking about.

I got a written estimate from B of £2097.38 (in VAT). It says "To excavate defective concrete floor to lounge and renew, 50mm sand blinding, 1000 guage visqeen, 100mm polystyrene insulation, 100mm concrete, trowelled to a smooth finish.

Despite 2 calls reminding him, and assurances that he really will drop off a written quote 'tomorrow', I've yet to get anything off C.

Can anyone tell me if B sounds OK -is this what is required? - he's a member of the Federation of Master Builders so I believe I can obtain insurance for around £75 via them for if anything shuld go wrong.

I'm a single mum (so very skint) and fully aware of how easy it would be to baffle me with technical talk and science.

Any thoughts?

Thanks in advance

Beverley

woodbutcher_2

B is the right way of doing it,except that it doesn't mention hardcore,which should be compacted every 150mm.Two feet is about the right depth to excavate but should be dertermined by how solid the earth is.The general rule of thumb is to dig down to solid clay but this is not always feasible.I don't know if the price is good or not as it is hard to say without seeing it but it doesn't look too unreasonable.It's a big job and 2 feet of digging generates one hell of a pile of muck.