insulation under screed - best insulation ?
Hi one and all,
I built an extension and now need to screed the floor.
There is 135mm to play with between the old floor line and the current
concrete slab top.
I was planning on insulating above the slab and under the screed. (No
underfloor heating, just hoping to improve insulation and maybe gain a
bit of heat from passive solar gain) The room is a kitchen and
measures about 4.7m by 5m. The walls are block with a 70mm plus cavity
(fullfill eventually) and there is a floor above - ie two storey
extension).
I was planning on putting 70mm of insulation in and a 65mm screed but
have just had a crisis of indecision since getting quotes from the
local builder.
They recommend Kingspan TP10.
I thought that this was for roofing and having used it in the roof I
know that it is pretty weak and I would have thought not ideal in
compression.
They have given me prices for the following:
Kingspan Kooltherm K3 (50mm)
Jabfloor 70 (50mm)
Kinspan TP10 (70mm)
I haven't seen the K3 but from the online literature from KSpan it
looks like I can use K3 or TF70.
Is TP10 the wrong material ?
Whatever insulation I end up using I was hoping to avoid cracking by
using mesh.
I was going to add some wrapping mesh (D49) or chicken wire at the
bottom of the screed.
However I read that it is a good idea to stop cold bridging by using
20 to 25mm of perimeter insulation.
I would have thought that this will lead to more compression of the
insulation ? THen you have a floating layer of screed with insulation
all around.
I want to lay tiles and don't want to find a floor cracking and
sinking after a few years....
Any thoughts on this ?! Help ! What is the standard way of doing
this ?
Thanks for any help.
Ed
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