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Extensions

Thinkness of roof insulation

Anonymous user 09/03/2024 - 3.00 PM

Weve had a lean to extension to the rear of our house and I now need to insulate roof The roof has 8x2 rafters I am wondering what thickness of celotex I need to use between the rafters? Can I use 100mm and have 100mm ventilationor would it need to be 150mm to leave 50mm ventilation?

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4 Answers

Anonymous user

150mm celotex insulation wil Achieving a better U value 50mm is plenty of space for ventilation this will pass building regs
Answered10 January 2019
0

D & R Refurbishments

Rating: 5 out of 5
Romford
Hi John your probably better putting 175m celotex in between the 8x2 timbers with a 25m Air vent witch would make better insulation for this Room many thanks hope this helps you. Thanks Darren At D&R Refurbishments
Answered10 January 2019
0

Anonymous user

Hi I would advise you to use 150mm rockwool before boarding it and you will have a 50mm space for it to ventilate properly, hope this helped. Si from S.A interior and exterior
Answered11 January 2019
0

C&C Construction

Rating: 4.9 out of 5
St Albans
id advise 150mm in between and insulated board over to stop thermal bridging building regs do an have asked me to do this a couple of times.
Answered21 January 2019
0