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Underfloor Heating - advice please
Posted: 14 Mar 2007, 14:04
by DamianB
I've just removed the mostly rotten, suspended floor in my living room and want to put in UFH. I'm planning to put DPM down first, then 50 or 100mm of Kingspan/Celotex with 50mm against the walls to create a well for the concrete slab. It seems logical to me to maximise the depth of this slab (less 65mm for pipes and screed layer) in order to maximise thermal mass. Am I missing anything here?
Posted: 14 Mar 2007, 14:13
by kenneal - lagger
Some companies like to put the insulation between the oversite concrete and the screed with the pipes on top of the insulation to improve the response time. This is also said to increase the controllability.
I've had two houses with the insulation under the oversite and I've not had a problem with overheating. You do have to put the heating on earlier but, at the same time, you can turn it off earlier. If you run it at the lowest circulation temperature that gives comfort, you shouldn't have any overheating problems. Run it at a low circulation temperature most of the time for economy and bump the temp up manually when it's really cold outside.
Hope that helps you make up your mind.
Ken
Posted: 09 May 2007, 00:51
by kenneal - lagger
I've just reread my reply. I didn't say anything about the insulation. It's probably cheaper to put a thicker layer of polystyrene in instead of Kingspan/Celotex with the DPM on top of the insulation.
You need a 65 screed on 100 oversite concrete. More concrete won't make much difference.
You will only get one chance to insulate this floor so I would go for 200mm of polystyrene or, if you're worried about thickness, 150 of Kingspan/Celotex.