Now the frame is dry, we hop on the roof and start cutting a hole for our new Maxxair Fan! Installing your own roof vent van in your campervan conversion is not too daunting a task (especially after cutting out a hole for a window) but you do need to make sure you have the right tools and waterproof it properly.
2. WHERE DOES THE FAN GO?
We already knew exactly where we wanted to install the fan, but now is your last chance to make up your mind. If you’re having only one extraction fan, having it nearest your kitchen is the best idea; with our layout, the kitchen is in the back.
We used the frame to mark out four lines of the hole size we needed to cut, being sure to centre the frame in the middle of our ceiling. 🎯
Be sure to use metal cutting drill bits when drilling through the van. We had a pack of ‘for metal’ drill bits, but they weren’t tough enough to cut through the steel of the van. So instead we got a set of titanium tipped drill bits, which worked amazingly well.
A set is not expensive, and it’s worth buying one for your whole van conversion anyway.
3. BIN BAG PROTECTION
Before cutting out the hole, tape a bin bag beneath the part you’re about to cut out in order to catch any metal shards and the actual piece of metal you’re cutting out, otherwise, you’ll have a very messy cleanup job.
4. MAKE A HOLE IN YOUR ROOF (ON PURPOSE)
Next, we hopped up on the roof (remembering to bring all our tools, gear and also a power extension cord) and prepared to cut the hole.
We cleaned the area with our dwindling alcohol supply, drew four border lines on the roof as a guide, used the pre-drilled holes as a guide, put duct tape on the bottom of our jigsaw to prevent it from scratching the roof, and cut! ✂️
It’s best to cut 2 sides fully, cut the 3rd one nearly all the way, but leave a few mm remaining.
Then when you cut the 4th side all the way, it won’t fall straight down, and you can cut the remainder easily.
The duct tape trick, it sort of worked but still scratched the van, and some of the metal shavings stuck to the duct tape, so not really sure we’ll use that trick again.
5. SANDING, TEST FIT, AND RUST PROTECTION
It took a few tries, and because the roof ribs don’t allow the plastic housing to sit flat, it can be a bit tricky.
Once smooth and fitting nicely, we removed the bin bag and used Hammerite to rust protect the edges of our newly cut hole. 🖌️
6. STICK ON THE WOODEN FRAME
After making sure it was all lined up (ish), we hoovered any runaway metal shavings, and had lunch. 🥪
Leave the sealant to dry for a few hours. We left ours to set for only an hour or so, and as soon as we tried to screw screws into it, it fell off and was a hassle to hold in place whilst screwing the fan back on.
7. NUMPTY ALERT – REMEMBER TO DRY FIT
Before fitting the butyl tape, dry fit the plastic fan housing and mark with a pen where the screw holes are. 📐
This will allow you to accurately position the butyl tape so that the screws actually screw into the tape, plug their own hole and increase the water resistance of the area.
8. BUTYL TAPE
Since the van ribs make the fan sit unevenly, we need to level out the fan’s plastic frame base.
Instead of hitting the ribs with a hammer (not a good idea), we built layers of butyl tape in the gaps to make it level and add waterproofness.
We also ran a full length of the stuff on top of everything once it was level, to give the plastic housing something to grip and stick to.
9. SCREW IN THE FAN HOUSING
The self-tapping means, in theory, you shouldn’t need to predrill a hole, but we did anyway since they didn’t catch without a pilot hole – understandable since it is a stainless steel roof. 💪
10. STICKY STICKY SEALANT
With the frame in, we went around the edge with some Sikaflex 512 – you need a certain sealant for this job as it not only has to dry flexible, be a neutral cure and be waterproof but also has to resist UV since it’s exposed to the sun.
We probably went overboard, but we don’t want this thing to leak. We also covered all the screw heads in sealant since they will also leak if not covered. 💦
11. FAN IS OPEN FOR BUSINESS
Finally, we slotted the actual fan into place and secured it with four side mounting screws into the little metal brackets (oh, and don’t install the fan backwards).
We tested the fan with a 12V supply to ensure it worked, but for now, it shall remain unwired until our electrics are done. ⚡