We have just purchased an old Welsh cottage the walls are slate 600mm thick, floors are concrete in poor condition with evidence of damp.

My idea is to re-screed use Limecrete for the floor with foamed glass insulation or possibly to just Limecrete/glass around the edges 100-150mm wide and Celotex/concrete screed the main parts.

I plan to do all the work myself so i can keep costs as low as possible.

Any advice of experience with this or a similar product would be much appreciated.

Yes have installed the Welsh version (google limedotorgdotuk;) with tiles set in lime to make sure whole floor could ‘breathe’, so suggest go all the way, don’t use modern or non-breathable elements in floor, that way much more like original building would have been made.

Also if a concrete floor has been added any below GL damp can be forced up through walls, but lime should help re-balance, unless fundamental water issues. I do like the glass blocks, just make sure you get enough and of course have the depth to dig out and not undermine walls.

use waterproof concerte..

google “Sika waterproof concrete”

The slate walls are impermeable, so make the floor impermeable. If the cottage is damp then install and good ventilation system.

A friend of mine has addressed similar issues recently. It’s only been in a year or so, but so far so good. She’s incredibly switched on with these sorts of things, and has building health as a core goal. This is from an open home she did recently…

[url=https://flic.kr/p/29rmDJ9]image27[/url] by KingOfBrad, on Flickr

coconut, installing a ventilation system is a bodge not a fix. Waterproof concrete is clearly not the solution here. Let it breath!

If you are doing the limecrete yourself make sure you get some proper guidance on how to do it.  Many years ago there was a Grand Designs project where they put down a limecrete floor which just did not harden.  After waiting for weeks, they just had to dig it all out. 🙂

For some guidance see http://www.buildingconservation.com/articles/hydraulic/hydraulic.htm

or download the briefing on Lime from https://www.spab.org.uk/advice/spab-briefings

Many years ago there was a Grand Designs project where they put down a limecrete floor which just did not harden.  After waiting for weeks, they just had to dig it all out.

Which from memory was put down by a builder with no prior experience outside during the autumn or winter.  I also recall thinking that it looked far too wet a mix when it was laid (looked like the builder assumed it could be mixed and used exactly like concrete.  Limecrete does take an age to reach a reasonable strength and is susceptible to cold a wet weather while it does so.  Its not a quick fix.  I’ve put down quite a few over the years using the aerated ceramic beans (sorry lifespan’s too short to look up the trade name) as an insulated underlay.  Whether you use it or not is down to; what you start with in terms of the surrounding walls; what you want to cover it with.  If you want to put carpet underlay down, vinyl flooring, glazed tiles, or sealed stone slabs I wouldn’t bother because your negating the benefit.

The alternative is a concrete slab spaced off the walls with a ventilated gap, which will give moisture an escape route other than wicking up the walls.

Thanks all for the information much appreciated, there is much to process and i am now waiting on quotes for materials.

The condition of the sub floor will have an impact on how we tackle this, if it is reasonably dry then a hybrid solution of a breathable trench adjacent to the walls is probably the compromise solution.

Damp is only really present at the edges of the floor, the external walls are suprisingly dry even though a large part are a metre below ground level.

The folks at Ty-Mawr are really helpful, give them a buzz/check out their website