Dormer Roof Insulation and cold in winter
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Dormer Roof Insulation and cold in winter

Post by stephen.bates45 » Sun Feb 05, 2023 4:04 pm

We have a bungalow with a dormer roof which has vented soffits in cold weather the soffits allow cold air into the roof so the edges of the ceiling are colder and moisture condenses on these cold areas which leads to mould. I have recently fitted a loft hatch to allow access to the roof space and have seen that there is a membrane on the top side of the plaster board ceiling which seals the moisture in. There is insulation in the roof which has been pushed out to the roof which I assume prevents ventilation which the soffits are intended to provide.
My question is what can I do to prevent moisture condensation at the ceiling edges? Do I actually need ventilated soffits can I cover most of them with insulation and use something like this in a few sections ... el-vents-0
The Roll Panel Vents are designed to maintain a flow of air to the roof space from the eaves, thereby allowing the escape of built-up moisture. Made from a continuous single profile, the panel can be rolled out over several rafters to create a ventilated gap beneath the felt running the span of...
Any suggestions or ideas would be much appreciated.

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Re: Dormer Roof Insulation and cold in winter

Post by stoneyboy » Tue Feb 07, 2023 10:44 pm

Hi Stephen.bates45,
Even if there is a vapour barrier above the plasterboard damp will still get into the loft through perimeters, piercings and loft hatch so you must keep loft ventilation.
The roll vents could be cut to fit between the rafters as a retro fit which would allow you to carry the insulation into the soffit area.
Regards S

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