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Do i need a gap between the insulation and the roof tiles

I have a old barn ive just re-done up.
I read that i need a gap between the insulation and the roof tiles. But i don't have any as the plaster board is fixed to the roof ridge. there is insulation on the sides. (The ceiling go right up to ridge and the top pearlings). My roof has no felt just slate tiles. Should i go to the expense of a new roof??

The roof has recently leaked but have fixed the roof tile back in place.


4 Answers from MyBuilder Roofers

Best Answer

Normally need 50mm airspace between underfelt and insulation, however because yours does not have underfelt an airgap is not needed as enough ventilationwill come through the tiles - i'm sure building control at yor local council will verify this.

Ideally though with iles you should have underfelt or preferably breathable membrane


Answered 28th Jun 2011

you should have rafters holding your roof up and to conect your lathes to,
you nail your roof tiles to on one side and the plaster board on the other,
these will be 3,4,6 inch deep. this is where you put your insulation , usually a solid form ,like kingspan,
you allow a 25mm air gap between the insulation and the underfelt.
then tile as normal,
you will need a builders notice from your local building regulations to carry out this work,
they will inform you what depth of insulation you will be allowed to install,


Answered 27th Jun 2011

Hi. Space between insulation and roof tiles is necessary to let air flow. Otherwise you can have a problem with condensation in the ceiling. Usually timber and insulation are designed, in the new builds with some cavity gap.



Answered 27th Jun 2011

Yes you will need a sufficient gap for air flow other wise it may cause condensation and damp will appear in your roof and ceilings. I can't tell you to have a new roof but if you need assistance you no where we are.


Answered 27th Jun 2011

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