insulation necessary with UFH?

L driver · 09-11-2010 01:06AM #1

Hi,
Is insulation necessary between hollowcore and screed with regards to ufh? If the house is very well insulated and airtight does the insulation at this point become irrelevant, note that HC is within the thermal envelope and there is no cavity.

sydthebeat · 09-11-2010 02:27PM

in a zoned heating system different zones wil lheat different areas, thus insulation is required. about 40mm would suffice.

in theory it may not but in practise there will always be heat loss.

its also and aid to a quicker response which is vital with UFH

Mellor · 10-11-2010 05:46AM

Insulation under UFH is actually totally unrealated to the thermal envelope. It's there to ensure that a higher percent off the heat is directed upwards to the living space, and as little as possible into the hollowcore slab, which doesn't need any heat in theory.

Wil have an immediate and direct effect on heating bill.
Stick in 40mm

L driver · 10-11-2010 08:40AM

Thanks Syd/Mellor,
I think upstairs will be one zone, not much point trying to have different temp in rooms with doors open and hrv in my opinion. I was thinking along the lines that when the house is up and running that the HC and screed should be a thermal mass together and that by putting in insulation I would be losing this to some extent? But thinking now that the 40mm, as your advise, would be the best advise, and when heat is called for that the load is lessened.
Thanks again

insulation necessary with UFH?

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