threshold between concrete slab and limecete perimeter

[elamcc]

Hi all,
I'm renovating a tiny stone house, 3.5 m by 4.20. I've poured a central concrete slab interior leaving a channel to pour a limecrete perimeter.
I have also poured a slab on the exterior of one side to add a glass extension and again left a channel to pour a limecrete perimeter.
I've heard worries of the concrete expanding. Has anyone used any particular material like cork in between as an expansion joint?
thanks for any advice

 

[88v8]

Hello and welcome.

You know that you have to float the limecrete on glass or LECA? Some say that it's the underspace created by the LECA that actually dissipates the damp, but anyway.....

And on the Limecrete the flooring tiles or whatever must be laid in lime and pointed in lime and not sealed or covered in anything impermeable.

But to answer your question, no need for any expansion joint but I hope you made some provision in the concrete slab(s) for them to key to the limecrete.

Here you can see the breathing perimeter we laid over our all-limecrete slab. Reason for the 6" quarries is they have more pointing area than the flags, and a stone floor breathes mainly through its joints.
The perimeter varies in width around the irregular room, but never less than 12".



Ivor

 

[elamcc]

thanks Ivor,
That floor is a beauty.
i have the glapor foamed glass. I've poured a pure limecrete floor in a previous outbuilding so will use the same method.
Will be interesting to see how the hybrid compares.
thanks again, much appreciated

 

[elamcc]

Hello and welcome.

You know that you have to float the limecrete on glass or LECA? Some say that it's the underspace created by the LECA that actually dissipates the damp, but anyway.....

And on the Limecrete the flooring tiles or whatever must be laid in lime and pointed in lime and not sealed or covered in anything impermeable.

But to answer your question, no need for any expansion joint but I hope you made some provision in the concrete slab(s) for them to key to the limecrete.

Here you can see the breathing perimeter we laid over our all-limecrete slab. Reason for the 6" quarries is they have more pointing area than the flags, and a stone floor breathes mainly through its joints.
The perimeter varies in width around the irregular room, but never less than 12".



Ivor

I realise that limecrete floors don't use steel in them. Is there a method/ material you could advice to use to key to the concrete slab? a slab that already exists. Thanks again, Elaine

 

[88v8]

I realise that limecrete floors don't use steel in them. Is there a method/ material you could advice to use to key to the concrete slab? a slab that already exists. Thanks again, Elaine

Mmm, no, no rebar because the slab will be 'damp' and the lime would corrode it, and in any case the slabs are usually quite thick and not weight-bearing.

I suppose, you could have left some stainless rebar sticking out of the concrete slabs, or stepped the edge so the limecrete has something to sit on... easy to be wise after the event.... I generally find by the time I finish a job I know how I should have done it...

How wide is the perimeter?

 

[elamcc]

i know, living and learning
Perimeter is roughly 10"