New surface covering for victorian solid floor and damp proofing

[Flipjango]

Hi, we're just about to buy a victorian detached house. We are going to be knocking together two rooms and adding a small extension to make a bigger kitchen. One of the rooms has what we have been told by the surveyor is a victorian (so not concrete) solid floor. He's explained that the terracotta tiles on the surface act as the damp proof layer. The other room has a timber suspended floor. We want to take up the solid floor terracotta tiles, and lay a new parquet floor across the whole of the new room, levelling out the various floor surfaces, so we can link together the three areas, but I'm not sure what to do with the solid floor.

The house has some problems with penetrating damp, mostly due to massive neglect, leaking gutters and a layer of cement render that has been added to some of the walls which water is getting behind. We plan to remove the render and repoint with lime mortar and use lime plaster inside to regain breathability. The timber and damp surveyor (independent so not trying to sell us anything) did suggest injecting a DPC, which we don't plan to do as I feel it causes more problems than it solves. He also suggested that if we removed the terracotta tiles we should add a layer of something called Oldroyd Xs to create a damvproof membrane to the floor. My worry is that by changing the characteristic of the existing floor we may cause damp problems to the walls.

I was just wondering what everyone though? Is this the right way to proceed? IF not, what would you suggest?

 

[MatthewC]

Just bumping this up as it's had no replies and was slipping down the pile.

In my experience a Victorian solid floor is nothing more than a load of loose infill (whatever rubbish they wanted to get rid of), covered by a shallow layer of some weak lime mortar. I don't see how the terracotta tiles can act as a damp proof layer - they might pass the damp upwards to the atmosphere, but that's about it. You'll have dampness there which will affect your parquet floor. Can you lift a tile to see what it's like?

If your surveyor suggested doing an injected DPC then frankly his advice is not to be trusted - if he isn't a salesman then he is just unknowledgeable. You need to keep the breathablity of the floor (as you know) and you want a dry floor - the only way I know of doing that is to dig out and do limecrete floor. I note you haven't mentioned the outside - what is the ground level outside, compared to inside? It needs to be several inches (6-8 ideally) below the internal floor level.

Sort out all the damp issues working from the top. I did all this on my house seven years ago - it was a lot of work and a good cost, but it was well worth it - warm and dry with no sign of anything modern used at all! (See my blog - click on the contact bubble on the right)

Matthew

 

[plasticpigeon]

I suppose you could dig out the solid floor and make it suspended if you added air bricks in the right place to make sure it was ventilated. personally I think it would be a shame, as it is nice to keep the original floor finish. Quarries are very nice, and although the floor won't match throughout, it would be interesting as you could see where the original rooms were.

 

[Flipjango]

Thanks for the replies. I accidentally didn't subscribe to the thread so didn't realise it had had responses. I think we are leaning towards a timber suspended floor as then we can have the same type of floor across the whole room. The rear of the house is a couple of feet about the ground level so plenty of room for air bricks. I really feel the cold and it'd also be nice to be able to insulate the floor at the same time. Quarry tiles make me shiver at just the thought of putting my feet on them on a cold morning.

Our architect has suggested we'd struggle to pass BC on the extension with a suspended floor though as we'd need to have high insulation levels. I'm still not sure what to do there - whether we have concrete in the extension (modern construction so totally different wall structure) and then timber across the rest. The solid floor is in a pretty terrible state anyway and is very tiny - only around 6m2.

 

[a twig]

Our architect has suggested we'd struggle to pass BC on the extension with a suspended floor though as we'd need to have high insulation levels. I'm still not sure what to do there - whether we have concrete in the extension (modern construction so totally different wall structure) and then timber across the rest. The solid floor is in a pretty terrible state anyway and is very tiny - only around 6m2.

Allegedly if you aren't planning on selling the house any time soon you could forget to notify...

 

[Flipjango]

Nice idea, but as its a massive refurb (as the house is currently derelict) I think we'd probably be taking too big a risk. As much as anything else, I guess B/C are looking out for our safety. Nice to know someone is checking the builders work. Not sure we'd be there forever either so probably best to do it right.