Upstand for a velux rooflight on a 15 degree pitch roof

[Lots2learn]

Hi All

We have fitted today two out of three velux windows and I am not entirely happy about the look. They look a bit clunky and protrude significantly above the roof and ridge line. 

The roof is a 15 degree pitch which has 18 mm sarking and will have a membrane fitted over then finished with raised seams aluminium roof material. 

The recommendation is to recess to the red line on the window which makes it quite a protrusion above the 150 mm upstand. I understand the rationale is for protection against ingress on the shallow/slow draining roof. My thoughts are we have 150 mm upstand and the windows are close to the top of the roof so is this overkill? We also live in a dry area, near Cambridge. 

Can anyone else who has a similar roof format with roof lights share information and photos of how theirs was fitted. 

[PeterW]

I think from memory the total protrusion should be 150mm, not the frame itself which is why it looks so high. They would probably be better fitted onto a 50x50 block but I would also be concerned about the cold bridge with that size upstand. 

[Cpd]

Sorry no experience in low pitch installation but that definitely looks to high, hope someone can help with the detail needed. 

[PeterW]

Who specced the install ..? According to the installers guide, a velux window should be red line flush with the roof surface with an EDE flashing. What was the purpose of the kerb..??

 

Handbook is here if you want a copy.