Renault Trafic Vivaro rooflight install. Dometic Heki mini skylight fit to ribbed Mark 2 high roof.

How I fitted a Dometic Heki style mini rooflight or skylight to my Renault Trafic (Traffic) Mark 11 (2001-2015 Second Generation) high roof (hightop) camper van.
Some owners I believe squash the deep ribs to get a flat roof but I wasn't confident that I would get the edges flat enough to bed the rooflight down and not get a leak.
This mini rooflight is cut out to 400mm square (40cms x 40cms). The roof ribs are at 200mm centres.
I installed the rooflight dead centre which meant cutting along the length of the two outer ribs and across the centre rib.
I could have cut across two ribs and sunk the rooflight into the channels and not centred on the roof. But my brain could not accept this somehow. I couldn't picture how it would work and I like symmetry. However, you might want to try that instead of my method.
This was a retro installation. That is, I converted this 2011 former South Lanarkshire Council builder's van a few years ago. I used as many donated and upcycled parts as I could. I was given several 8'x4'sheets of 4mm MDF so the ceiling is cut from 2 of these. With enough joists or wooden battens to screw to, they have not warped after 2 Scottish winters.
The combination of retro-fit, the rooflight sitting on top of the ribs, and not wanting to countersink or set the lower rooflight fascia section inside the ceiling, gave me a challenging gap to solve. You can skip that section of the video.
I fitted the rooflight in very hot weather where the Sikaflex sealant was quite runny and the steel roof was burning my skin. So after screwing the rooflight in place, I left the final surrounding bead till cooler temperatures. In the interim, we had a thunder storm with pounding rain and it did leak. I suspect there was a tiny gap where the butyl strips layered up to meet the contour of the ribs. However, once I had gone round the entire perimeter with a generous bead of Sikaflex, it has remained dry through several rain storms.
I hope this video helps you decide how to go about your installation even if it is for a different model of van. I also hope it gives you the confidence to tackle the job with enthusiasm and not too much trepidation!
Comments always welcome.
Thanks for watching.