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Loft insulation against rafters on an old roof with no felt lining under the tiles

I want to make more use of the loft space and ideally want to insulate and board up the roof to create an clean insulated space. The situation is as follows;

- No lining under the tiles
- Tiles and roof are in a good state
- Pitched roof with excellent head space
- loft space is NOT ventilated (I cannot see any grills in the fascias

What are the best insulating options available to me without redoing the roof tiles and laying down felt?

How do I ensure that there are no damp and condensation issues?

1 Answer from a MyBuilder Insulation Installer

Best Answer

so long as you keep the required 50mm air space between the back of the insulation and the back of the tiles you will be ok - it is a better situation than if you had old style bitumen roofing felt as this does not breath, the tiles will breath due to gaps at laps etc.
This was discussed only last week with my local building inspector.
You will need a minimum of 50mm pir under the the rafters.


Answered 6th Dec 2014

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