Currently refurbishing my sitting room in a 60's built bungalow. I knew the concrete floors in all the rooms were in a poor state, being unlevel and sounding 'hollow' in places. The plan was to strip off the original Marley tiles and lay down self levelling latex.
However, after eventually getting off all the tiles (b*tch of a job!), the floor was in a much worse state than I had thought. There were some pretty big cracks, and in some areas it looked like the slab had lifted and sounded very 'hollow'. So out came the SDS bolster chisel… I was initially quite pleased to discover that it was a very poor top screed that was the problem. Ranging in thickness of 3/4" – 2" (!), it came away from the main floor slab quite easily, the slab underneath appeared to be quite solid and sound.
I then made a very strange discovery, see pic below… A diagonal channel through the slab about 2" wide. I initially thought it was a tree root, as there was signs of rotten wood, but it was too straight. It runs from wall to wall and cuts the slab in half, I can only assume it was put in when they laid the slab at the point they ran out of concrete! But diagonally?! It think the process of the wood rotting was the main cause of the screed cracks. Digging through the channel showed the slab to be about 3" thick, but straight on top of soil, no apparent hardcore or DPM.
So, I'm left with two options; either bodge up the 'gap' with concrete and lay a new screed over the top, but the top surface of the slab is very sandy so I wouldn't be confident it would adhere. Or to do the job properly, break up the whole floor and re-lay with DPM and proper insulation.
If I go for re-laying it, I've thought I might go for a suspended wooden construction, as I can do the whole job myself, and figure it will be cheaper and I would not have to excavate down as far.
Would appreciate comments / opinions / suggestions.
Many thanks.
However, after eventually getting off all the tiles (b*tch of a job!), the floor was in a much worse state than I had thought. There were some pretty big cracks, and in some areas it looked like the slab had lifted and sounded very 'hollow'. So out came the SDS bolster chisel… I was initially quite pleased to discover that it was a very poor top screed that was the problem. Ranging in thickness of 3/4" – 2" (!), it came away from the main floor slab quite easily, the slab underneath appeared to be quite solid and sound.
I then made a very strange discovery, see pic below… A diagonal channel through the slab about 2" wide. I initially thought it was a tree root, as there was signs of rotten wood, but it was too straight. It runs from wall to wall and cuts the slab in half, I can only assume it was put in when they laid the slab at the point they ran out of concrete! But diagonally?! It think the process of the wood rotting was the main cause of the screed cracks. Digging through the channel showed the slab to be about 3" thick, but straight on top of soil, no apparent hardcore or DPM.
So, I'm left with two options; either bodge up the 'gap' with concrete and lay a new screed over the top, but the top surface of the slab is very sandy so I wouldn't be confident it would adhere. Or to do the job properly, break up the whole floor and re-lay with DPM and proper insulation.
If I go for re-laying it, I've thought I might go for a suspended wooden construction, as I can do the whole job myself, and figure it will be cheaper and I would not have to excavate down as far.
Would appreciate comments / opinions / suggestions.
Many thanks.
