I am trying to insulate between rafters in my roof. There is no loft and at the moment there are slates, then sarking and then plasterboard. I want to remove the plasterboard and cut Kingspan to go between the rafters, then replace plasterboard. Do I have to use any waterproof membrane? or is it as simple as I think?
kingspan between the rafters
- Thread starter cathneill
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Hi cathneill,
In short, yes you can, but you do have to follow a few rules...
1. Make sure that your existing roof is watertight and will remain so (ie no missing slates, holes in sarking etc)
2. Ensure you keep a 50mm ventilated cavity between the insulation and the top of the rafters.
3. You will need a vapour control layer (VCL) on the underside of the rafters if you are just fixing plasterboard. However, in order to meet building regulations / standards, the use of an insulated plasterboard such as Kingspan Kooltherm K18 Insulated Plasterboard would be needed. This contains an integral VCL, and will also help reduce thermal bridges.
Hope this helps.
In short, yes you can, but you do have to follow a few rules...
1. Make sure that your existing roof is watertight and will remain so (ie no missing slates, holes in sarking etc)
2. Ensure you keep a 50mm ventilated cavity between the insulation and the top of the rafters.
3. You will need a vapour control layer (VCL) on the underside of the rafters if you are just fixing plasterboard. However, in order to meet building regulations / standards, the use of an insulated plasterboard such as Kingspan Kooltherm K18 Insulated Plasterboard would be needed. This contains an integral VCL, and will also help reduce thermal bridges.
Hope this helps.
thank you so much. will tell builder all this incase he doesn't know. Didn't want to do something that would cause damp in the future. Cath
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