Damp concrete floor in extension, tiles breaking

[cammy0102]

It will establish what is screed and what is concrete. If it goes straight through to DPM then you will know:- The whole floor needs redoing and existing will break out easy.
If it penetrates 2" and then buckles you have a 2" screed topping an acceptable concrete oversite. and replacing screed under broken tiles may be limit of works.

Sorry for my ignorance. Is the DPM under the concrete then? Is it DPM, Concrete and screte from bottom to top?

 

[joni os]

Sorry for my ignorance. Is the DPM under the concrete then? Is it DPM, Concrete and screte from bottom to top?

Hardcore ; DPM ;Concrete; Screed. was normal for 1980s build. A 4"nail should not penetrate any DPM.

 

[cammy0102]

Hardcore ; DPM ;Concrete; Screed. was normal for 1980s build. A 4"nail should not penetrate any DPM.

Ahh OK gotacha. thanks.

 

[cammy0102]

If it's not a current plumbing leak, it's still possible that it was water that was trapped in the floor (screed) from the previous leak about a year and half ago especially since that leak was very close to the currently affected area. In that situation I'd imagine it's difficult to say it's a badly laid floor or it's the water from previous leak trapped in the floor. How do I proceed in that situation? Can I just remove the floor tiles in the bathroom and install waterproof membrane and re-tile?

 

[sparkie30]

If it's not a current plumbing leak, it's still possible that it was water that was trapped in the floor (screed) from the previous leak about a year and half ago especially since that leak was very close to the currently affected area. In that situation I'd imagine it's difficult to say it's a badly laid floor or it's the water from previous leak trapped in the floor. How do I proceed in that situation? Can I just remove the floor tiles in the bathroom and install waterproof membrane and re-tile?

You best take tiles out then take about 100mm or more off screed/concrete then lay dpm and 75mm celotex then screed then electric underfloor heating then tile.

Decent job me thinks

Good luck.

 

[Radioman]

If you can rule out a water leak from feed or waste pipes that would be good. Then If the damp area is situated around the old brick wall that was originally an external wall of Victorian age I would guess that there was no DPC on that wall. Hopefully Whoever did the extension was supervised by building control and put in a physical DPC on the new walls and floor but probably didn't bother on the existing wall or maybe did a chemical injection that has now failed. Excavate and replace as above and then knock off all plaster up to 1 meter and re inject.

 

[Frog67]

Drain test should sort out if plumbing related.
As stated above, your gonna have to dig into floor to examine oversite.
Check outside for damp course in brickwork and how low the patio slabs are from this level. From memory the slabs should be 150mm below.

 

[lame plumber]

could just be you laid tiles on a damp base, seen it before, new concrete not left to dry long enough, I would start by removing tiles, cleaning up base and see if it dries or if there is an underlying issue. take your time

 

[cammy0102]

As I mentioned before, the old floor tiles in the bathroom and kitchen seemed to be fine and I didn't notice any cracks. So if it's been damp for a number of years surely those tiles would have cracked too?

I've contacted the council to see if the original owner in the 80s acquired Building control for the extension. They charge about 50 pounds to do a search!

 

[Radioman]

Hard landscaping should be a minimum of 2 courses of bricks below the DPC , more if possible. A Henry French Drain should be at least 300mm deep and 150mm wide and constructed like this