Concrete base sloping inwards in new property Drainage pipes, concrete, footings and foundations. Post your questions and find answers here

[Swan99]

Just bought a new place and I knew it had damp issues and 2 sloping and bulging floors which I thought would be levelled by taking up the floor and replacing what I thought would be rotten joists and reinstating the air bricks
I ended up taking off 8 different types of flooring that some one has laid in various locations (including self levelling compound which had been poured in puddles)
A lot of the slopes and all of the bulges were down to the many layers of flooring.
I am left though with a concrete base which does still slope.

I know the house was flooded about 50 years ago and I know there is potentially water getting in via a number of routes which I am in the process of putting right.

1. Could the sloping be due to the flood and it sank after the flood but hasn’t moved since
Or
2. After the initial flood the continuous water seepage in is lowering the slab/s bit by bit although one of the 2 rooms doesn’t have water seeping in and is dry.
Or
3. Could there be cellars
Or
4. Is something else going on

I know it all points to subsidence but there is no cracking of the building, the doors open and shut easily. Everything else apart from these 2 floors is level.
No cracked windows or any of the usual signs of subsidence apart from these 2 separate floors.
The floors in between are level and have no slopes.

[stoneyboy]

Hi swan99,
With the age of your home it is possible that the concrete floors were laid on loose fill uncompacted hardcore. This may be the reason for not level floors. You could check for cellars by hitting the floor with a hammer, a hollow sound over the whole floor indicates a cavity = cellar or sunken sub-base. You could core drill the floor to establish what is there.
Regards S

[Swan99]

Interesting about the cellar idea.
I thought I had remove every layer in one of the rooms that sloped but found there was one more layer to go.
Having removed that layer I have found a bit at the lowest end of the room where there is a definite hole where the concrete slab looks like it finishes and then there is what looks like floorboards.
I can put my fingers into the hole and can’t feel anything below.
So at the moment I have a layer of DPM which stops short of the internal wall, a layer of concrete which might or might not be the slab base, then floorboards which are lower than the top of the concrete
The kitchen is at the front of the house on the opposite side of the building and is perfectly level but the room behind is the other room which has the slope. I punched a small hole in the wall between the kitchen and sloped room just above the skirting to look through and it looks like the kitchen floor is floor boards. I can’t see anything below atm
I think definitely getting a torch and camera to look under areas that already have gaps is the next step.

Still have a few more layers to go in some rooms that are level but have also had various levels or flooring added to them
The carpet super glued and nailed every 10cm to the tongue and groove boardIng which then appears to have been sunk into a concrete layer which is attached to more thick boarding is a particularly slow process at removing.

[stoneyboy]

Hi swan99,
Good luck with your investigation - hope you don’t find anything untoward.
Regards S

[Swan99]

Started to chip away at the gap where I could see floorboards and managed to get a couple up thinking I might find a cellar or joists only to find what I think is the actual concrete base and some wiring that was laid without protection on top of the floorboards and then concrete poured over.

I think someone has put in gas central heating and rewired the place.
Instead of doing things properly they have put down floorboards, then laid the pipes and wiring on top and then poured concrete on top with no protection
The sloping is because pipe are thicker than wires and they have laid the concrete thicker on the side of the room that has the radiators and pipe work and haven’t put as much down on the other side

The hallway tiles came up yesterday
I removed one tile near to the radiator and underneath was a copper pipe (now green and wet) directly under the tile. The only thing between the tile and pipe was the tile glue.






I now have to take this concrete base up very carefully

[stoneyboy]

Hi swan99,
Wow, what a shocker. Thanks for the update.
Regards S

[Swan99]

Anyone know of a good pipe and wire locator

Judging by the direction of the bit of pipe that was under the hall way floor I think they have run the pipe work across the middle of the floors as well
Fortunately my son trained as a plumber. He said he would help with the plumbing if I made sure there were no spiders and bugs. (He hates creepy crawlers when they are inside the house.)

Note the words trained as a plumber.