Concrete tiled floor damp

[SUZYBABE]

Found another problem just after ive sorted the guttering and roof out. My floor is very damp and one tile has dipped near middle door. Ive taken the tile up and underneath is very soft {not too sure} maybe sand,cement,soil etc. I put a stick in and it goes down deep. Ive got white efferescence salts on some of the tiles.

The floor sounds hollow in places. Very scared ive blown it and the house is a right off.

Had a builder in who showed me wet marks near chimney breast and hes convinced i have an old boiler thats been blocked up and is leaking hes also convinced a few of the old pipes are not capped creating dripping into
the floor. Hes comming back tomorrow to take up a couple small bits just to check if his theory is right.

Ive also noticed since going up ladders that my kitchen flat roof has got no lead flashing and has exposed brickwork and wood which could be letting water in.

[welsh brickie]

well with regards to the floor you can either take the lot up and lay dam roof membrane etc.
Or have a firm come in and lay ashphalt on top creating a flat damp proof surface.
The house is never a right off,there are always problems with every house just do a bit at a time.
With regards to the damp around the chimney breast,there could be a back boiler with leaking pipes as your builder suggested,but you wont know unless you rip out the lot.

[SUZYBABE]

well with regards to the floor you can either take the lot up and lay dam roof membrane etc.
Or have a firm come in and lay ashphalt on top creating a flat damp proof surface.
The house is never a right off,there are always problems with every house just do a bit at a time.
With regards to the damp around the chimney breast,there could be a back boiler with leaking pipes as your builder suggested,but you wont know unless you rip out the lot.

The builder came to my house he made a hole in the side of the wall to check for any leaks. He said he felt all inside and no leaks what so ever he removed the copper pipes that were not in use {once he showed me his corgi card}

Hes now told me i have sulphate attack in my concrete under the tiles . He pointed the the cement under the tiles and said sulphate attck turns the concrete to dust . He also mentioned the effloresence in the corner was due to sulphate attck.

Hes given me a estimate of £10,000 to sort the problem out .This involves digging out all the cement etc to a depth of about 500mm and putting fresh concrete and a dpm etc .

He gave me another option for £2000 that involves putting down k11 damp proof system to tank and seal it up.

My walls show no sign of bulging the floor is not uneven except for a couple of tiles which are out of line.

very confused

[welsh brickie]

I suggest you get other quotes and a quote for an ashphalt floor,dont commit to anything before asking for further advise from proffesional builders,not plumbers.

[andy01]

just be aware that if the concrete floor has failed due to sulphate attack, then so may your concrete strip foundations. if you have more concrete poured make sure it has a high cement content. gen 3 is not good enough needs to be something like grade C35/40 - cant remember exactly