A very suspicious mark

[WD40solvesall]

Hi All,
I hope I can get some advice? I’ve just chucked away my washer AND dishwasher for a variety of sins, one of which is stealth flooding of my kitchen. I say ‘stealth’ because it was a slow drip behind the machines so I didn’t see the damage for a long time. Also, one of my floorboard has rotted away with the damp! So most of the water went down there.

I am now trying to dry it all out before buying a new washer and dishwasher (I’m getting sick of washing things in the bath). Whereas some of the damp has receded, I’m still very suspicious of one damp spot which I think has got bigger not smaller. It is around a crack in the concrete in the middle of the floor.

My parents are a dab hand at concreting and they say that it’s probably just taking a long time to dry out because of the length of time it’s been subjected to my leaking machines. Plus my heating has stopped working, so that’s not speeding the process (I’ve not have a good month for appliances). However, I’m still very suspicious of that dark, damp looking, mark. I’m imagining that it gets bigger when it rains but can’t be sure.

Could anyone recommend things to look for to see if there’s another reason for the wet? It might be relevant that it’s damp around the fault line in the concrete. My kitchen is not part of the original house. The house was built in the 1930’s and I suspect that the extension/kitchen was added later....possibly at a time when it was acceptable to play fast and loose with building regs.

Any suggestions would be gratefully received!

 

[tony1851]

Salts from the ground, maybe? They can absorb moisture from the air and make it look like rising- or penetrating damp

 

[Alastairreid]

There probably wont be a dpm below the concrete! Any ground water leeching thru will take the path of least resistance through any breaks in the floor.

Your best course of action if this is the case would be to install a liquid dpm.

Plenty of threads on the subject in flooring.

Is your kitchen floor wood and concrete?

 

[JohnD]

Some photos would help.

Draw a pencil or chalk outline round the wet patch, and write the date on it. Draw and date another line each time it changes. Then you can see if it is getting bigger or smaller.

Waterpipes in and under floors often leak. How old is yours?

 

[WD40solvesall]

Thanks for responding!

Draw a pencil or chalk outline round the wet patch, and write the date on it. Draw and date another line each time it changes. Then you can see if it is getting bigger or smaller.
Waterpipes in and under floors often leak. How old is yours?

Good point! I will try the chalk trick. I have a device that checks for pipes behind walls, I'll see if it goes off if I run it over the floor.

Is your kitchen floor wood and concrete?

Wood about 80cm into the room (I suspect the original boundary of the house) then it's solid concrete. The floorboard that rotted away was the first one next to the concrete.
I'll have a look at some of the threads you mentioned.