Damp in Quarry Tile/Ash floor

[Spoilt Victorian Child]

I went to look at a 2up 2down (1900-1910 or so) terraced house. The house had all fireplaces bricked up and central heating/UPVC windows. The back of the house was cement rendered.

The front room had suspended wooden floor. In the back room the floor was solid. But damp had stained the carpet that had been laid over the quarry tiles, and damp had also crept up the wall (about a foot high) in the same corner. Please see diagram below.

I have a few questions:

1. The wall the damp was on was the party wall, so quite internal. I'm really puzzled as to why the damp occurred in this particular spot and nowhere else in the room?

2. What would be the best way to cure this damp? (Googling around, I've read that quarry tiles on ash/soil need to breath and should not be covered. But I can understand why they'd been covered as I grew up with exactly this set up, and they are freezing).

3. A lot of builders/DIY forum I've looked in have advocated digging out the ash, putting down insulation, a waterproof plastic sheet, and then laying concrete. This could also give the neat option of putting in underfloor heating in and re-laying the quarry tiles. I suspect that concrete won't help the overall situation though?? What would be a smarter way of doing this sort of thing?

Thanks!

 

[Roger H]

Hi. Well, the damp could be condensation if the building isn’t well ventilated. There’s a lot to explore on damp in previous threads if you search.

Re lifting the tiles though, I’d want to maintain breathability. If you really want to take them up you could relay them on a limecrete floor with leca or glassfoam underneath to insulate. You could add wet underfloor heating.

Maybe add a couple of pipes through from your suspended timber floor passing through the tiled floor to get periscope air vents to the back yard – creating through-ventilation under the subfloor.

 

[agbagb]

Have you checked where all the pipework goes? It could also be a leak from the kitchen (yours or next doors), possibly the mains incoming. If it leaks under the kitchen slab that could well be where it would show. Also check the external wastes and soil pipes in case they are leaking through under the floor.

 

[Spoilt Victorian Child]

Yeah, was expecting this to be a condensation issue more than anything else, but it doesn't fit with other condensation problems I've come accross.

The kitchen sink, waste pipes and the radiator (which is in the room) are all on the opposite walls to the side with damp, so logically the house's pipework wouldn't be anywhere near it. I did wonder if the neighbour had their kitchen the other side of the wall, but no. Their pipes could be though, I suppose, so that could be an explanation.

What's the rough cost of getting jobs done with limecrete vs concrete BTW? Is it twice the price, thrice...?