cross ventilation and issues with roof design with lantern

[martysmarty]

Hmm, well im looking into how i could use the abutment vents in an upstand but cant find any examples. My roofing knoledge is very limited as a diyer.

I am tempted to swap it out for a warm deck somehow. And get it past bc.

As i already have the superfoil, i checked their website snd they have a warm roof solution using sf40, and 35mm hd board. This would push the height of my roof but not by a massive amount.

See this
https://www.superfoil.co.uk/week-19-warm-flat-roof-insulation-0-18-superfoil-solution-series/

 

[freddiemercurystwin]

http://www.glidevale.com/article/70...e-a-cold-flat-roof-and-which-product-do-i-use

 

[martysmarty]

http://www.glidevale.com/article/70...e-a-cold-flat-roof-and-which-product-do-i-use

Right so, they look decent

So i could fit these as woody has stated on the upstand perimiter then? They look a lot better than the ones i saw that were more aimed at being inside a soffit and looked like they would let water in.

Il look into those and come back. I really apreciate this guys.

 

[catlad]

A warm roof is a better solution, speak to your building control guy about your concerns and he might be willing to let you build a warm roof even though it might be a little higher than it should be.

 

[martysmarty]

my problem becomes when using the vents in the upstand is forming some sort of guard in front of the vent at the top of the tophat to stop the rain getting in. fv250 it seems are used with a lead flashing formed in front of it.

the design has definitly caused me a bit of a faff! catlad, you might be onto something there. i would of thought they would be in favor of a warm roof even if it was 100mm taller...

i can see there's ways around it.. but.

 

[martysmarty]

Spoke to my architect. As it turns out he thought he had specced it as a warm roof already. I told him no its a cold.

Hes going to get back to me today with a new detail

 

[martysmarty]

Still waiting on the info for new roof layout.

One other thing that i forgot to ask, the steel beam that is over the window taking the load point of the sky lantern trimmers, is specced at 152 x 89 x 16 with an 8mm plate welded under it to act as a lintel to the outer leaf bricks.

I just want to be sure i cant just use a normal galv outer leaf cavity tray, and just use the steel beam on the inside? I can see why its not a catnic due to load point, but i cant understand why the need for the 275x8mm plate welded to take the outer leaf? Its going to be like 4 courses high.

Only asking as i see rust marks being an issue long term with the render. Iv seen it on other houses

I dunno maybe im being picky. I suppose hammerite on top of red oxide will hold up more than i think.