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What if you have an old, non-breathable felt roof covering and you want to insulate your roof?

Chris Brookman
Member Admin

In this instance you need to make sure that you have at least a 50mm gap between any insulation between the rafters and the underside of the felt. You will also need to ventilate at eaves and ridge level to ensure there is enough air movement to carry away any moisture. The rest of the insulation is then fixed below the rafters as necessary to achieve the correct U-value.

Topic starter Posted : 09/03/2021 5:33 pm

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