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Vapour control layer

Hi I'm in the process of building a single story flat roof extension. The flat roof has 2 roof lanterns. 2000mm x 1500mm. It is a warm roof construction and I will be using a visqeen vapour control layer. My question is do I take the vcl up the External sideof the roof lantern upstand or under the upstand construction and return up the inside of the roof lantern upstand?

2 Answers from MyBuilder Roofers

Hi, if it is a self built timber upstand where your lantern just sits on they yes you can continue your VCL on the lantern upstand because your insulation thickness. You could either fold the excess over the top of your insulation or leave behind the flashing from your upstand, depending on what roof system you use.
If you require anything else please feel free to ask.

Mid-West Roofing


Answered 13th Dec 2017

All vcl must be installed at least 100mm above the insulation level on all upstand detail areas this is a must for all the best felt suppliers (eg bauder langley)who inspect the installation of commercial roofing


Answered 29th Dec 2017

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