Air gap above insulation, and saggy sarking

[oldbilly]

I've just started putting 100mm Ecotherm between the 150mm rafters in my pitched roof kitchen. Technically this should give me the required 50mm air gap beneath the insulation and the breathable membrane. Unfortunately I've just discovered that the roofer left so much crap lying on top of the membrane -- cut-off bits of slate, I suppose -- that it sags down between each pair of rafters and touches the top of the insulation.

The question is, does this matter? If it does, I might be able to do something about the sag, but it's a lot of bother.

The other question is, is it common practice for roofers to do this?

Cheers!

 

[theprinceofdarkness]

The air gap is to vent any moisture that occurs over the top of the foam. So where it touches I would think there is a continous gap right out to under the tiles and where the joists are the gap will exist, I would not worry. The whole thing is a bit theoretical , because unless this gap is actually ventilated at the eaves, it won't be ventilated.
Frank

 

[oldbilly]

Thanks, Frank. Will stop worrying!