How ToVauxhall Movano Campervan

Fitting the roof vent – Vauxhall Movano Camper Van Conversion

So I was hoping to write a blog post about how easy it was to install a roof light in my self build campervan, but instead I will be writing about the problems I encountered.

Looking online, a lot of people said they fitted a roof vent to their vans in about 3 hours. For me, that should read nearly 3 days. You see, the company which used to own the van let their work guys walk all over the roof of the van, and this has stretched the strengthening “ridges” in the metal and left me with a floppy roof!

So when installing a roof light, you need a nice flat surface – which is always a little harder on a van because of of the ridges – but in my case, the roof could be “popped” up and down. So the job I faced up to was not only getting a flat surface, but also reforming these “ridges” to take up the “slack” in the metal caused by people walking on the roof in the past.

Installing the roof light

The first thing was to mark up the cut lines on some masking tape. The square I needed to cut was 39cmx39cm. We measured about 10 times before committing to the cut! Its always a nervous moment as you cut into the metal for the first time. To cut the hole we used a 1mm cutting disc on an angle grinder, and this made short work of cutting through the metal.

I made sure I covered the interior of the van in old sheets as lots of metal sparks were flying around. I also made sure the roof was thoroughly cleaned afterwards (and hoovered!) to remove traces of metal that could rust later.

So with the hole cut, it was time to file back any burred edges, and then treat all the newly exposed metal with red oxide primer, and then some silver touch up paint.

And here is where things start to get interesting!

Encountering problems!

As I mentioned above, the previous company which owned the van let their workmen walk all over the roof. This meant normal roof “ridges” had been stretched, leaving the metal floppy and bowed. This meant my new roof vent would not fit properly as it needed a flat surface to clamp too.

So after lots of thought, we came up with the idea of how to reform the ridges, and take out the slack in the metal roof. We used some pieces of perspex cut to the width of the ridges and made sure the depth of the perspex was greater than the depth of the ridges on the roof. We then placed the pieces of perspex into the channels on the roof, and into the ridges inside the van – and then clamped the whole lot together using two pieces of heavy duty angle iron – 1 inside the van and 1 on the roof.

This had the effect of stretching the metal to form bigger “ridges” and “channels”, and in doing so, took up the slack in the metal. For a closer look, have a look at these photos.

We repeated this on both sides of the roof light hole. And it worked! It took out a lot of the slack in the metal and strengthened up the roof nicely. This allowed the rooflight to clamp down squarely onto the roof.

Sealing with Sikaflex

So the next job was to fill in the roof channels to the same height as the ridges. To do this I just stuck the perspex into the channels using Sikaflex 512, and then temporarily clamped the roof light down into position (without any additional sealant – so if it had rained at this point it would have leaked!!) I then left it like this for 24 hours to allow the Sikaflex to go off, and then removed the rooflight the following day.

I was now close to finishing the installation. All I had to do now was liberally place a load of Sikaflex 512 into the grooves on the roof vent, and squirt a load onto the roof and perspex. Looking online it is suggested not to scrimp on using the Sikaflex, so I used almost a tube (around 300ml) to install the roof light.

When the the roof vent was clamped into position, and the Sikaflax oozed out and created a good bead of sealant all the way around the roof vent. I then took a damp cloth to wipe up any excess and try and make it look fairly tidy!

After doing the final tightening of the screws, I topped off the screw heads with a dollop of Sikaflex to seal them in. With everything now in place, it was time to set back and relax – at least until it rains, when I will find out how well I have managed to get it to seal!

So they you have it. I started the job on a Tuesday, and finally finished it on the Thursday morning. I am really pleased to have got this sorted, as at times I was wondering how the hell I was going to straighten out the metal roof. My original plan was for two roof lights, but after the hassle of installing this one, I will have to make do – because I ain’t going through this again! haha :)


  1. Have there been any leaks?

    I plan on having someone do nearly the same thing with the same fan. The only concern for me is that I’ve heard people say these fans leak sometimes when they are installed on a ribbed roof. I hope this is just something that can be sorted out by having it properly installed.

    1. I haven’t had a leak from it. I used a lot of sealant, and its been doing its job. I did take my time to get it right though, as the roof was all bent to start with, as you saw in the article.

  2. My van is similar to yours, however my rooflight needs to be mounted on a roof of thickness 25-85mm and my roof is 10mm thick. From your pictures you seem to have used timber to give yourself a thicker mounting point on the inside of your van. What timber did you use and did you varnish it?

  3. Hi I just bought Opel Movano and pretty much making copy of yours :D hope you dont mind. Anyway I have a question. Why sikaflex 512? My friends recommend me sikaflex 221i and 295uv so I am kinda confused. Thank you for answer.

    1. I saw 512 recommended, so used that. I have also used 221 on the side windows. I don’t not what the difference is – they all seem to work haha

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