1930's concrete floor, ditumen dpm

[dormermike]

Hello

A solid concrete floor with bitumen on top, I was wondering how deep it is likely to be? Trying to track down a damp problem (i've posted loads about this previously) and am going to take a brick out of the wall to look into the cavity, but also considering taking some of the concrete at the wall/floor junction to see what is beneath it. If the ground is saturated, it may be worth ripping the whole lot up. If it is coming through the wall, then it is more likely penetrating damp, etc.

I've been researching 1930's concrete floors and it may well be just a couple of inches straight onto earth/soil?

Thanks
Mike

 

[kbdiy]

Have you eliminated the other possibilites before you go cracking open the concrete floor - which could be much thicker than you expect unless you are sure it is original to the house. What is the ground level like outside? Where is the damp course in relation to the levels inside and out? Does the bitumen meet the damp course to give a complete membrane?

 

[dormermike]

Hi

The bitumen does not meet the DPC to give a continuous membrane, no. The DPC is approx 1.5-2 inches above the DPM, hence why the bricks are wet. **

Assuming the floor is original how thick would it likely be? It seems solid in most places when i stamp my feet, though some areas sound a bit "echoey".

** EDIT: Before I go sealing it all in though, I am trying to eliminate the source of moisture. If the slab is 2" thick sitting on soil, i'll rip it all out. If its likely to be substantial, i'll explore other options. I am also going to try and get a high res cam and some bright lights into the cavity this weekend near the damp spots so i can see "behind" the damp brickwork. A boroscope (cheapy, res was poor) suggests water droplets in the cavity. I also have a CCTV survey of drains due in Sept.

 

[kbdiy]

As there were no regs to speak of in the '30s then the thickness is anyone's guess. Sounds like you might just have to make a mess to find out.

 

[dormermike]

Thanks - yes i thought that might be the case

Considering drilling a hole straight down, as there is no DPM to break apart from the bitumen, it should be easy to guage the concrete depth.

 

[pred]

Before you rip everything up where is the damp coming from?

Quite often the drains built in brick have passed their sell by date, if you dig them out and replace them with plastic underground traps it might cure your problems, you will have to cut the salt glaze pipe and put an adapter on to take the plastic S&V pipe.