Roof Ventilation - roof with no soffits or fascias - how many roof vents?

[RobRiotUK]

Hi there,

I'm hoping someone can help advise.

I've had two roofers out to look at my attic space, as there is inadequate ventilation in the ceiling void and therefore we've had issues with condensation collecting on the roof felt in winter and it being extremely hot in the summer.

Both roofers suggested installing roof vents in different quantities. So I wanted to check which was correct.

Our roof has no overhang, so doesn't have any soffits or fascias.

One said install 3 at the front, and 3 at the back. The other said install 5 at the front (due to gable) and 6 at the back.

The attic space is 364 square feet (34 square meters).

I realise I need some decent intake and exhaust ventilation. So I suppose my first question is, would roof tiles alone - some near the eaves and some near the ridge - provide this? If so, how many do I realistically need?

I've supplied what was suggested by the last roofer below.

 

[RobRiotUK]

Can anyone advise? Thanks

 

[noseall]

Can anyone advise? Thanks

If you read any amount of posts on this forum, you will quickly understand that domestic condensation related issues are unique and idiosyncratic. Your neighbour could have an identical house but with zero problems. Any amount of ventilation is good, the more the merrier. A draughty loft is a healthy loft.

Mitigation of moisture travel is also a good idea, i.e. sealed loft hatch, vapour-check ceilings etc. As is ridding the house of moisture in the first place i.e. ventilation and taking care with wet washing, boiling pans of water etc.

No one should stop breathing though.

 

[RobRiotUK]

Thanks for your reply. That makes sense. I was trying to ascertain which of the two roofers was more on the money I guess. But considering what you've said about "the more the merrier" in regards to ventilation, the 11 roof tile option is probably ok.