Victorian Terrace ~ Remove concrete floors or have DPC injected?!?

paddyrg

If you've got the time and patience to redo the job nicely, it may be worth replacing the concrete floor...with another concrete floor (nothing inherently wrong with them if done right). Then you can put in the membranes, bitumen, whatever and the house should be happy again. If he hangs doors so the glass will smash, I'll bet there isn't any kind of damp membrane, so you have a big moisture wick which will never come good.

If there already pipes embedded in the concrete, you've got some breaking up ahead of you no matter what. And you may even find bigger horrors under the concrete which you'd need to address sooner or later - maybe he packed the space with offcuts of wood (ie the old floor) then concreted over - so in a few years the slab will crack and all kinds of worse problems show up?!

cavegitl

From what I have seen and read...the way a typical Victorian terrace is constructed the concrete floor is the problem, and it may be irrelevant whether it was properly laid with DPC or not.

The internal walls go down further than the concrete, so where there would once have been breathable suspended timber floors, that gave the moisture somewhere to escape, there is now a solid substance (ie concrete) that can't breath and hence the water is finding its way up the internal walls instead.

I was reading several expert comments on the issue (google victorian houses and concrete floor for funsies ;-)) and they say over and over that concrete floors should not be put in Victorian houses with airbricks and suspended timber floors. However, i'm sure building regs say something about insisting on concrete (although this probably applies to modern built houses with damp proof courses in all walls).


It's a bloody minefield!!

cavegitl

Jess Howell of the Telegraph writes this (which probably explains the issue better than I am doing);

"What a shame they didn’t take the opportunity to get rid of the concrete, and reinstate the building to its original state, which would have meant a suspended timber ground floor, ventilated below by airbricks in the walls.
Solid concrete floors in Victorian houses often lead to dampness problems, regardless of the presence or otherwise of a damp-proof membrane below the concrete. This is because the concrete traps moisture in the ground below it, leading to high localised humidity. And the absence of the through-flow of subfloor ventilation can lead to a moisture build-up in the brick walls".