Roof Fan Installation

The roof fan installation was one of the more challenging aspects that we expected to face in this van conversion. Firstly, cutting into the van is an irreversible change that you don’t want get wrong, so we were both more than a little nervous about doing it. Secondly, the fan itself was one of the more expensive items that we had invested in so far for this conversion.

After reading various reviews and watching other YouTube van conversion videos we decided to go for the MaxxFan Deluxe. It boasts many impressive features such as a rain sensor that automatically closes the lid, ten different speeds for both intake and exhaust and the ability to clear out 25m² of air in one minute, we considered it worth the slightly higher price tag than that of it’s rivals. Along with the fan we armed ourselves with the following items for installation:

The first step was to make the timber frame that would be stuck to the inside of the roof using the SikaFlex and the base of the fan on the roof would be screwed into the wooden frame. We grabbed some 45×70 ‘kortregel’ timber from Hornbach and cut it down to size to match the 40x40cm MaxxFan dimensions.

With our newly created frame we waited for a weekend of minimal rain. In the midst of winter in Gothenburg we knew we were never going to get clear skies and no wind, but since we were cutting a whole in the roof we at least needed no rain! Finally our blessings were answered one Sunday in January and whilst sporting a mild hangover, we performed the inevitable cut into Myrtle’s topside!

To protect the inside of the van from metal shavings, we opened up a plastic bag and taped it around the area of cutting. We also taped both sides of the cutting line to help dampen the vibration from the jigsaw. Another good tip is to tape the bottom of your jigaw guide to prevent it scratching the chassis of the van.

After measuring up (not twice, but three times), we cut the pilot holes in each corner using a powerdrill fitted with a HSS drillbit, followed by the eventual cut using the jigsaw. Since we were worried about cutting the hole too big, the first cut ended up being about 2mm too small so we had to file and cut a little more down until we had a nice snug fit.

The next step was to attach the frame to the inside of the roof using the SikaFlex 512 adhesive and clamps in every corner of the frame. We then used the mastic sealing tape to fill in the spaces between the vibration absorbing ridges in the roof and to provide a flat, level surface for the fan to sit on. Unfortunately we did not have enough sealing tape, so we rationed it out in sections and filled in the spaces with SikaFlex.

After we finished applying the sealing tape and SikaFlex on the topside, we placed the fan’s frame on top and marked out the frame screw holes before drilling them with the pilot hole. We had to be careful when drilling the holes, since we didn’t have time to let the SikaFlex on the wooden frame adhere to the roof, so one of us held the frame while the other drilled the holes. We made the mistake of not holding the frame for the first hole and it ended up coming loose! With the holes drilled we placed the frame back on and screwed it into the wooden frame.

As you can see in the picture above, we still ended up with about a 5-10mm gap between the roof and the frame due to the ridges. Since we didn’t have anymore sealing tape we ended up having to fill this gap with a LOT of SikaFlex. It wasn’t pretty, and it was a pretty hack job, but it was enough to get the gap filled for now. Once the frame was secured we inserted the fan housing into the hole and secured it into the frame using the four screws provided, and voila, the fan is installed!

To wrap up the installation we just needed to grind off some of the screw tips that had penetrated through the wooden frame. Here’s a pretty slow-mo gif of that being done:

Update: About one week after the installation it rained heavily and we discovered a small leak in one of the corners 🙁 It was not a big surprise considering the large gap we had to fill with SikaFlex and although we were disappointed to discover the leak, we were happy that it was only a very small one. There will be a follow up post on how we fixed that soon!

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