There comes a point when watching van tour videos on YouTube changes. It morphs from let’s see the cool things to how the hell do you actually build those things?! Then, there’s a point where you notice that before we start building anything inside, we need to start cutting holes in the roof and walls first. We need that MaxxAir Fan.
Why cut holes first?
We are opting to cut the major holes for several reasons. First, we want to make sure the holes we make won’t leak. We can check if we sealed around the holes better with nothing else in the van. Second, if we build the ceiling, then cut a hole through the metal, we would also have to cut through wood. Those wood cuts would probably get pretty janky. Third, we thought it would be easier to clean up the mess of metal shavings and other debris in an empty van.
What’s the reason behind cutting a hole in the roof?
Ventilation. Ventilation. And ventilation! When you live in a metal box and you breathe, it creates moisture. This moisture builds up over time and creates problems. The main problem being: mold. Mold is no good.
In our last van, we had several small windows that we could open and that worked well enough, but not great. For one, the windows that opened did not have an insect screen. Due to the lack of insect screens we were faced with either having ventilation or keeping insects out. This is not a fun choice. Although, we did get good at smashing mosquitos on the ceiling and cleaning them up in the morning.
For Polysprout, we wanted to get a roof fan which could both draw air out and bring air inside. While cooking or showering, with a MaxxAir Fan, we can switch it to bring the air outside of the van. This would work much like the fan you have in your house shower or over the cooktop. However, when we go to bed, we can switch it to bring cooler air inside when it’s warm.
To make this work even better, we will also add a large window to the sliding door. We chose a window that can slide open to one side that includes an insect screen. With this window cracked or open and the MaxxAir Fan on, we will have cross-ventilation. And cross-ventiliation is our ultimate goal in cutting holes in the van. If you’d like to know more about why we chose to place the fan where we did, check out Conversion Log Entry 2: Solving the Limited Roof Real Estate Dilemma.
Prepping for Cutting a Hole
When we went to cut the hole for the MaxxAir Fan, we made sure we had all the parts first and understood the process. Like everything we have found so far: the directions were lacking. So, we hit up YouTube and found a few videos that all had slightly different ways of accomplishing the same goal.
In one video, we discovered a template to use between the roof and the van to make the roof surface more even. Until you’ve looked at the top of a van roof, you won’t realize that it’s sloped and has indented ribs on it. Why does this matter you may wonder? Well, when you think about the MaxxAir Fan being straight and the roof being curved with an indentation on two sides, you’ll notice a gap. This template fits snuggly into the ribs and makes the contour of the roof flat. Overall, by adding the template, it will create a better seal against moisture.
A template also exists on Ebay for the underside of the van. However, since we are putting the MaxxAir Fan in a very snug spot in the back of the van, it would not fit between the support pillars. The installation instructions for the fan did specify the need to have at least 1 1/8-inch roof thickness. Hence, Karma found some scrap wood in his Dad’s garage and built a wood frame to hold the fan inside.
We treated that wood frame with Vermont Natural Coatings Waterproofing and Caliwel Mold and Mildew prevention. Figuring that if a leak did happen, the wood frame would get the moisture first and not be noticed until it went through the ceiling.
Lastly, because we had a wood frame, we needed longer screws than the MaxxAir Fan provided. Using the power of the internet, we went and purchased the appropriate machine screws.
Actually Cutting a Hole in the Roof for the MaxxAir Fan
We waited until we had a weather forecast with two days of sunshine. Since the winter days have much less sunlight than summer, we wanted the extra time cushion. And we were definitely glad for it.
On the first sunny morning, we brought our supplies to the van and drew the outline of our hole onto the roof from the inside. From there, we made four pilot holes, one in each corner. Karma used bigger and bigger drill bits to expand the holes to the size of the jigsaw blade. We taped up a trash bag to catch as many of the metal shavings from cutting a hole as possible. Furthermore, even though they were far away, we covered the seats with an old sheet.
We nerve rackingly climbed up onto a piece of scaffolding and onto the roof with our assembled tools. We had five fresh sheet metal jigsaw blades with 30 tpi. After thoroughly mapping out the space with a sharpie and painter’s tape, we measured an extra time.
Karma and I took a deep breath and he used the jigsaw to begin making the first cut while I filmed. Let me tell you, a jigsaw through sheet metal is loud.
From a tip from a video on YouTube, we used the painter’s tape to vertically tape over the side of the square hole. This helped us reduce the vibration from the jigsaw in further cuts. We did this for each subsequent side of the square hole until the last side.
Since we opted to cut so close to the inside support pillars, we took those sides in a little. We figured it would be easier to shave off a little more than damage the pillars. Briefly, we grabbed the mounting flange from the MaxxAir Fan box and checked if our hole was the correct size. The outer sides were perfect, but as we suspected, we needed to shave off a tiny bit on the sides next to the pillars. However, it was much easier to do so when we could see the pillars that we did not want to hit.
All Extra Stuff You Don’t Think About
After seeing that the mounting flange fit the hole, we shaved down all the sides with a metal file. Now, I had thought the jigsaw through metal cutting a hole was loud. I had no idea how loud the metal file would be. At this point, random neighbors decided to casually take walks to the end of the cul-de-sac where we worked. I suspect the noise might have echoed more than we thought.
From everything we learned prior to cutting a hole in the van, we knew we had to hit the cut metal with primer and paint. No one wants rust to happen on a vehicle. And we definitely don’t want self-inflicted rust.
However, before we added a coat of Rustoleum to the 14 x 14-inch hole, we got the interior frame, exterior template, and the mounting frame attached with c-clamps. This allowed us to pre-drill holes through all three pieces and the roof.
When we unattached those items, we coated the edges and the pre-drilled holes with Rustoleum. Who wants rust to build up around a screw hole?! No one.
While we waited for the paint to dry, we attached the mounting flange to the exterior template from eBay with butyl tape. Waiting for the paint to dry distinctly felt like watching a pot of water boil. We also did a hefty dose of vacuuming and cleaning of the inside of the van. The trash bag caught a lot of metal shavings, but extra cleaning will never hurt.
When the paint did dry, we brought out the caulking gun and the 3M Window Weld that the template instructions suggested. If you want good instructions…the exterior template comes with the best instructions on van equipment that I’ve seen so far.
Screwing Everything In
What we did not realize was that caulking guns have thrust ratios and 3M Window Weld needed a caulking gun with a higher thrust ratio. Get your mind out of the gutter! This made attaching the template and mounting flange to the roof very difficult. I highly recommend spending the money on a caulking gun with an appropriate thrust ratio. More on that in the next conversion log. Trust me, it’s worth it.
At this point, with the shorter winter days, it was evening, and we had worked into the darkness. However, we wanted to get the machine screws into everything and let them settle overnight. We did that under a flood light.
Finally, we got to grab the fan itself and place it into the mounting flange. We adjusted the floating brackets to where we could add the side screws. Perfect!
Since time flew by and darkness fell, we covered the whole back of the van with two tarps to keep moisture away. Then, we waited.
In the morning, we uncovered the van and dried off any moisture that did get under the tarps. The sun baked it warm as we cranked the machine screws a little more. Since the butyl tape had squished a bit, that left room for a little extra tightening.
After tightening the screws, we used the Dicor Lap Sealant to create a waterproof seal around the template and mounting flange. Also, we covered the tops of the machine screws lest any water try and creep down there. Dicor Lap Sealant can be used with a normal caulking gun, by the way. It’s also what we used to seal around the roof rack, which you can read in my post here.
A day later, we added a second layer of Dicor Lap Sealant to make sure we had a thick waterproof barrier. We had noticed that as it self-leveled, some areas just needed a little more.
There you have it!
We survived cutting a hole into the roof of our van. Karma and I are both very relieved that we only have one big hole in the roof! Next up is an even bigger hole in the sliding door! Stay tuned.