We had planned on having a new flooring laid last week in our hallway, but = on lifting the old carpet the installers noticed that the floorboards were = very loose. They tried to secure them, but in lifting them they noticed tha= t the concrete slab on which they were sat was perishing.
House is a double fronted 1905 build, with the concrete slab only running t= hrough the central hallway (lounge / dining room on left and right of hallw= ay have suspended floors on joists).
I don't know why the hallway had a slab in there - perhaps to support the s= tairs which run up the middle of the house?
Anyway, clearly the concrete wasn't well protected from any damp, and the m= oisture has risen and caused some small damage to the ends of the joists fo= r both of the adjoining rooms. =20
It would appear there are two choices - dig out the slab, and replace with = a damp-protected new slab. Or dig out the slab, and replace with a suspend= ed floor. Second option has advantages for us in that we'd be able to get = the new flooring down soonish, whereas I'd expect to have to leave a concre= te slab for a period of time (2 months?) before putting the solid floor on = top of it (not a laminate, but similar). Is there a half-way house of some= form of using some pre-cast blocks to fill the hallway subfloor instead wh= ich might speed things up?
I presume the concrete slab which has failed runs straight through to the b= ack of the house too; and would expect that the bits I can't see suffer fro= m the same issues that the bits that we can. Where I can access under the = stairs there doesn't seem to be an issue. How concerned should I be to inv= estigate the whole lot?
Total floor area of the hall is only about 1.2m x 3.5m, so not a large area= . Pain in the arse though!
Matt