Limecrete floor

[El Greyo]

Hello all

In our small 17th century timber and brick cottage, we have concrete floors downstairs. Having worked on the ground levels outside and installed a french drain, we don't have a (touch wood) damp problem in the walls so we don't have an absolute urgent requirement to put in limecrete to cure a damp problem (although there is a mysterious dampish patch in the centre of the floor - not sure of source at moment). But we're working on the living room and I'm trying to improve the insulation all round and this includes a warmer floor. The concrete slab is very cold in winter but we haven't tried insulation on top of it yet to see how much difference that would make. The ceiling is low so I don't want to add too much that would raise the floor level.

So my thoughts are that the best approach is to remove concrete, dig down, put in leca insulation and limecrete slab on top. But it's a big job with lots of disturbance so I'd probably get an experienced firm to do it. As damp is not a serious problem I would think NHL 5.0 is appropriate.

My questions are:
How long does it take for a limecrete slab to set so that a) we can walk on it and carry on works to walls, ceiling, windows etc and b) until it is ready to use as a living room again? I know that it depends on environmental conditions but rough figures would be helpful.

Can anyone think of any other alternatives? T'other half has suggested battens and floorboards but she is quite a bit smaller than me and won't be bumping her head.

Also - anyone know of an Oxfordshire based building firm that will install a limecrete floor? And know what they are doing - because I don't.

Thanks very much
El Greyo

 

[robgil]

Nhl5 might be OK for the screed but the base I would use 3.5, I would expect at least 6 weeks of drying although it depends on quite a lot of different factors.

 

[JanJonWestWales]

hi, I laid a limecrete floor in our very damp hallway (See picture). with stone slabs on top
Its a much smaller area (6"x6") and took a lot of digging out, but it worked a treat and is as dry as a chip now.
I am planning to do the same in the living room but will probably get a company to do that.
I used NHL5 for the slab and screed, was fine (still dusts a little but not much)
took about a week to be able walk on and 4 weeks to be used normally.
great success, good luck !

 

[FamilyWiggs]

That's really good Jan or Jon. Thanks for sharing.

 

[MatthewC]

I laid a limecrete floor with LECA last year - see my blog http://houseintheenchantedforest.blogspot.co.uk/2011/04/fitting-limecrete-floor-part-1.html and later entries. We left it all for as long as possible but as I recall the slab was walkable in a week or so, ditto the screed. Then we laid flagstones and I left it all for more than a week before grouting but I think that was unnecessary. I used NHL5 as that was advised by Mike Wye.

I did this myself with a lad Chris who is very handy (he did my roofing), plus another lad as labourer - I provided the lime knowledge (i.e. regular advice from Mike Wye!). Chris lives just north of Oxford so could possibly help you (PM me). I could help if I only had time...

 

[88v8]

We had our sitting room done - about 12 x 13ft. 4" LECA & 4" lime. No screed, we bedded the flags onto the slab.
Agree, about a week to walk on it, perhaps less, depends on the lime. St Astier goes off faster.

To find a contractor, find a local supplier for the LECA/lime, then ask them to recommend, or failing that, ask them which contractors regularly buy from them.
That's how we found our builder, by asking Ty Mawr, but our builders are based in Abergavenny, a bit far for you.

Edit; when you dig out, be aware that you may end up below the 'foundations', if indeed there are any. The 8" we put in should be considered the minimum depth, even then we were below the keystones. This is not necessaraly a problem - it wasn't for us because we are on very stable clay, but be ready to follow straight on from digging to filling to slabbing so that the walls are not left unsupported for more than 24 hours.

Ivor

 

[El Greyo]

Thanks everyone for the replies, they have been very helpful.

I had originally thought we would do this ourselves but we have so much to do in the house that I am now considering actually paying people to do some work. The limecrete seems suitable as it will be disruptive, requires quite a lot of equipment and will be a lot quicker done by professionals.

Matthew: thanks for the tip. I'd like to have someone whom I don't have to supervise as I'm not able to take much time off work but as he's had the experience already, he may be useful. I'll drop you a line if I need the contact.

 

[rebeccac]

Instead of limecrete we dug up the old floor (earth and stones) and filled in with gravel then a compact roadbase (clay,sand,stone) mix onto that we laid old floor bricks ,bedding into a sand lime mix about 2cms deep.

www.myabruzzohome.blogspot.com