U-Values

Independent

Hi, I was wondering how to calculate the u-value for a ground floor. Do i include the screed, insulation, concrete slab, radon barrier, hardcore, muck. or do i stop at the radon barrier and leave out the hardcore and muck. Also which floor is best insulation above or below concrete slab? Thanks.

sydthebeat

Independent wrote: »

Hi, I was wondering how to calculate the u-value for a ground floor. Do i include the screed, insulation, concrete slab, radon barrier, hardcore, muck. or do i stop at the radon barrier and leave out the hardcore and muck. Also which floor is best insulation above or below concrete slab? Thanks.

you need to include everything.. even the earthwork...

above or below slab depends on your heating system..... mainly...
ie UFH = insulation above subfloor
rads = insulation below slab..

(generally)

Independent

Thanks, but still confused as how to do it, here is my spec the ground on our site is pretty much rock. We put 300mm of 804 stone on top of this, radon barrier on top of this, 150mm concrete on top of this. Now just need to know how to calculate for insulation and screed. Please could someone show me how to do it, thanks Ann.

sydthebeat

if your brave.. download buildesk 3.3 and input the details...

youll need the floor area and perimeter length....

it will give you accurate u values

http://www.builddesk.co.uk/sw49336.asp

Independent

Thanks syd i'll give it a go. My father is a retired builder but is not much use when it comes to the technical end of things!

ardara1

Independent wrote: »

Hi, I was wondering how to calculate the u-value for a ground floor. Do i include the screed, insulation, concrete slab, radon barrier, hardcore, muck. or do i stop at the radon barrier and leave out the hardcore and muck. Also which floor is best insulation above or below concrete slab? Thanks.

The heat loss thru a floor is mostly thru the perimeter edge - so you need to work out the perimeter edge length and divide that by the floor area (P/A)

Build desk is great - but for the UK - the thermal conductivity of the earth is different in Ireland than it is in the UK!!! - so be careful what you put in! Can not include concrete above insulation or floor coverings.

Mellor

I imagine it has a option toi adjust the ground conductivity. any half decent u-value calc i've seen does.

sydthebeat

here a screencapture of the input screen

youre given 3 choices for earth conductivity..
1.5, 2.0 and 3.2 depending on soil type...

Independent

Hi all, i am getting conflicting results from different sources for a u-value for our external walls. The build up is 20mm render,100mm block, 100 blown cavity insulation, 100mm block, 50mm composite board.
Thanks Ann.

sydthebeat

what product have you blown into your cavity, ann??

muffler

Would any of you mind if this and a couple of similar threads were moved to the Arch Tech forum. Im easy really but as the points being discussed are of a technical nature I think moving them may be best.

But I will go with a majority on this

smashey

muffler wrote: »

Would any of you mind if this and a couple of similar threads were moved to the Arch Tech forum. Im easy really but as the points being discussed are of a technical nature I think moving them may be best.

But I will go with a majority on this

I fully endorse this product.

Independent

Syd, its silver warmfil.

sydthebeat

Independent wrote: »

Syd, its silver warmfil.

thanks ann, and just to be sure.. .the composite board is kingspan or xtratherm???

47.5 = 12.5 plasterboard and 35mm Pu foam insulation....

Independent

Syd, the composite board is actually 30mm insulation 12.5mm plasterboard.

Independent

sorry xtratherm