loft conversion ventilation

[windy55]

Hello
I'm about to start my loft conversion (with the regs)
one thing i'm struggling to get my head round is how to achieve the roof ventilation. 50mm gap between the felt and the celotex no problem
eaves ventilation round vents, no problem, but what happens at the ridge.
I don't have the height to form an air gap at the ridge to ventilate from eave to eave
How do i get the continuous ridge ventilation without changing the victorian
ridge tiles
can i drill say 15mm holes along the ridge beam?

Thanks in advance

Michael

 

[MickBee]

Have you contacted the Building Control section of your local council for advice? It might be that you don't need ridge ventilation, if there is no felt under the tiles - or maybe you could fit breathable felt so that moisture can ventilate through the tiles.

I would be wary of your suggestion of drilling holes along the ridge beam. It might be pointless, because eaves-to-eaves ventilation only works with a shallow roof pitch, and by implication an empty loft, so that little moist air gets trapped at the ridge. It could also be potentially dangerous, because for the holes to be big enough to be effective for ventilation, they might seriously compromise the beam strength.

I am not a building expert, only someone who looked into ventilation when increasing the insulation of my (unconverted) loft. Hence my suggestion to make friends with the people who will be signing the Building Regs. approval certificate, before you start. Good luck with the job.

 

[Deluks]

If you're using breathable felt (and who wouldn't) then probably no worries. Otherwise you could fit tile vents near to the top.

 

[cmother1]

You might consider this stuff. Would mean re-setting all the ridge tiles though.