Vented soffit

[Jupiter01]

I have a double storey extension with the ground floor coming out an extra metre. This has a lean to roof. A portion of it can be seen in this picture.

Q. This roof is 10 metres wide and it has a vented soffit across he entire length. In winter, I can feel the cold air coming through the spot lights in the ceiling. Is the vented soffit necessary in this situation?

 

[DAZB]

I am assuming you have insulation in the ceiling space and if you Search eBay for downlight hood and install them over the downlights it will help to help keep out the draughts.

 

[^woody^]

A roof void is supposed to be vented.

The problem is your spotlights, and you need to deal with them and not the soffit vents.

Most people fail to realise that any spotlight in a ceiling is breaking the fire and smoke barrier of the plasterboard, and they just fit the cheap open spotlights. Fit proper fire rated units and this also solves any draught problem.

Plastic hoods won't do this, and you won't fit them through the holes in any case in your situation. Likewise for intumescent bags.

 

[Jupiter01]

Thanks. I do have fire rate and insulation- coverable downlights. They weren’t cheap either!
I appreciate that the void may require air but how much air? Currently the entire 10m length has vented soffits.

 

[^woody^]

Oh, ok you must have the type that are not completely sealed then. A sealed type should be draught free. Alternatively a sealed unit sold for bathrooms will definitely work.

 

[noseall]

Currently the entire 10m length has vented soffits.

That is normal. A drafty roof is a healthy roof. Deal with the air leaks not the roof.

 

[Jupiter01]

Thanks guys but are my vents "too generous" and hence letting in more draught than is required? How is this determined?
Even with the sealed lights, I assume there is cold seeping through the plasterboard and cavity?

 

[^woody^]

Cold air will be pulled down into a warm room via any gaps regardless of the vent stip.