flat cold roof venting options

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hi:)

renovating an 80's dormer and retrofitting pir insulation inbetween and on top of the timbers in the top floor.

we have had the roof tiles and dormers redone by a roofing company, and i'm in the process of ripping out the old insulation and retrofitting the new, which will be sealed/vapour barriered

I have one bedroom ready for overboarding and have concerns that there is no ventilation for the flat roofs. I have raised my concerns with the roofers they are being increasing hard to contact and i get the feeling have no wish to return.

so, from what i've read and researched what i should of had installed when they were doing the initial work was something like this
https://www.roofingsuperstore.co.uk...8ngTST7p1N-X2DTNOgxV6OOmEnxKTHehoCqAQQAvD_BwE

there is no space in the soffit area to install traditional circular soffit vents (maybe 35-50mm), is there any solution to install some kind of strip vent across the length of the roof?

maybe drilling out a series of holes and covering with a strip of something?

i was told the whole length of the ridge tile was also a vent, so if i could introduce venting at the front of the roof would this e sufficient to draw air through?

any other advice or suggestions wellcome

cheers




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Damn I hate seeing lead that didn't have patination oil applied....
 
i was told the whole length of the ridge tile was also a vent, so if i could introduce venting at the front of the roof would this e sufficient to draw air through?
Not on that roof it wont.

Shove the celotex tight up against the underside of the deck, fill between the rafters/joists with insualtion, vapour barrier before plasterboarding. No air voids = venting required.
 
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many thanks for the reply.

i'm assuming you mean No air voids = no venting required right?

so i would in effect changing it into a warm roof?

if i filled the flat roof parts what about where the small apex part is, i'd just leave that as it is now?

also i've done the vertical parts of the dormer also with an airgap, should these be filled so no air gap?

where there are discrepancies in the rafter height, from front to rear etc could i sandwich the pir board and fill any in between gaps with expanding foam?

i'll be overboarding with pir (maybe a thinner one in these areas) to stop thermal bridging from the rafters

thanks again
 

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