How to Install a Van Vent Fan

We know this sounds like a scary step, but just set a weekend aside, take a deep breath, and dive in (it also helps to do this project in a covered area in case it rains over the next few days since you’ll have a hole in your van roof or will be waiting for things to dry).

You’ll need to buy a vent fan, butyl tape to stick it down, some Flex Seal to waterproof it, and touch-up paint for the cut edges. We also highly recommend buying a custom adapter ring that fills any gaps or ridges in your roof (not needed if you have a flat roof). You could make one yourself out of wood, but to us the leak proof peace of mind was totally worth the money to buy a machined PVC one that fits perfectly. Impactproducts sells adapters on eBay for many van models and will sell you enough butyl tape too. We bought some high-tech goop to glue it to the van roof.

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Summary

Basically, from the outside of your roof you will draw lines along the inside edge of your vent fan receiving flange or adapter (these should be the same size), drill holes at the four corners, cut out the headliner on the inside of the van ceiling between the drilled holes (if required), then from the outside jigsaw a hole through the roof sheet metal. Whew. The scary part is over and it really isn’t as bad as its mental picture. Now you will glue the adapter onto the roof, screw the vent fan receiving flange onto it, seal the edges and screws, and screw the fan onto the receiving flange. You’re done on the roof now. From the inside of the van, wire the fan to your power source then cut the interior trim ring to size and screw that on. Oh, and it’s smart to test your vent fan before starting any of this to make sure it runs.

Check out our video step-by-step summary here.

Step-by-Step Procedure

Choose the Vent Fan Location

Decide where you to install your fan (forward, rear, etc.). We chose to put our fan toward the front, centered-side-to-side. You will also need at least 8″ of clear space on the roof behind the adapter for the fan overhang. Don’t forget to look inside your van ceiling to make sure you won’t hit anything important like electrical wires, lights, or structural supports where you will be cutting.
Put painter’s tape down where you will cut the hole.

Mark the Vent Fan Location

Lay the adapter on your van roof and trace around the inside of the adapter on the painter’s tape with a pencil. These will be your cutting lines.

Drill the Corner Holes

Using a drill with a small bit for metal, drill pilot holes through the 4 corners of the square.
Drill the holes again using a larger bit to make the holes big enough for your jigsaw blade to fit into.

Cut Out the Ceiling Headliner

Now, on the inside of the van, locate the 4 holes that were drilled earlier. Use a utility knife to cut the ceiling headliner out, if applicable, being careful not to cut any wires (we didn’t see any wires where we cut, but every van is different).

Cut the Hole in the Roof

Take a deep breath.
Cut the roof along the lines marked on the painter’s tape using a jigsaw and new metal blade. Having someone inside the van to catch the cut piece is helpful. If no one volunteers, cut 2 sides, duct tape them to the roof, then cut the other 2 sides.
TIP: The metal shards will be hot from cutting. Protect your van roof paint by covering it with towels or cardboard before cutting. Also protect your van interior by taping a hanging garbage bag around the hole to catch all the shards.

Prepare for the Adhesive

Remove the painter’s tape.
File the cut edges with a file enough to remove the burrs and sharp edges.
Put primer and paint on all the metal cuts to prevent corrosion. We used a handy primer and paint pen that we ordered in our original manufacturer’s color.
Dull the glossy paint a little with a Scotch-Brite scrubbing pad.
Wipe the adapter mounting area on the van roof with isopropyl alcohol and let it dry completely.
Set the adapter in place surrounding the hole.
Put painter’s tape down on the van roof about 1/2″ outside the adapter. This will give you a nice, clean line after installation.
On the bottom of the adapter, place three 1/8″beads (inner, middle, outer) of 3M Windo-Weld around the perimeter.
TIP: Warm the Windo-Weld up in the house before using if it is cold outside; this stuff is thick and squeezing out a small bead is a workout.

Install the Adapter on the Van Roof

Press the adapter very firmly onto the roof.
Smooth the Windo-Weld squeezout with a gloved finger for a nice radius between the adapter and the roof.
Wait 15 minutes then pull the tape up carefully.
Place a board on the adapter with some weights on top of the board and let it dry overnight.
TIP: We placed 50 lbs. of weights on a board for an evenly distributed load, but you could lightly clamp it instead.

Install the Vent Fan Receiving Flange

Put butyl tape around the bottom perimeter of the receiving flange that came with your vent fan where it will contact the adapter.
Press the receiving flange onto the adapter, making sure you have it facing the right direction.
Wherever there are holes in the receiving flange, drill pilot holes through the adapter and into the van roof for the attachment screws.
TIP: If the pilot holes go into a roof support beam, drill a clearance hole in the roof support beam.
Install the sheet metal screws provided with the vent fan receiving flange into the roof sheet metal.
TIP: If any butyl tape oozes out, trim it off.

Seal with Flex Seal

Cover everything you don’t want sprayed with Flex Seal with painter’s tape and newspaper. We placed painter’s tape on the van roof about 1/2″ larger than the adapter and 1″ up* on the receiving flange.
*After taking this photo we moved the tape higher on the receiving flange so the white wasn’t as visible on top of our black van.
Spray Flex Seal onto the remaining exposed area.
Wait at least an hour then pull off the painter’s tape.

Install the Vent Fan

After the Flex Seal is dry (read the can; 48 hours or longer for full cure depending on the surrounding temperatures), place the vent fan on the receiving flange and push down to seat it fully.
Install the screws provided with your vent fan to secure the fan to the receiving flange.
You are done on the outside of the van!

Connect the Electrical

Connect the electrical wires from the fan to the power source per the fan manufacturers’ instructions.
TIP: We secured our wires to the ceiling with zip ties.
Test it to make sure it runs.

Install the Vent Fan Trim Ring

Install your finished interior van ceiling.
The trim ring is long and probably needs to be cut down. Measure the height you want your vent fan trim ring to be to make both the exposed trim flush against the ceiling and the cut edges hidden.
Mark and cut the trim ring to height with a jigsaw or hacksaw.
TIP: Our jigsaw blade melted the plastic, so we went old school and use a small handheld hacksaw.
Screw the trim ring into the finished van ceiling using the screws provided.

TIP: We also added a chandelier (a warm white LED copper fairy light string wrapped around a flower-arranging hoop) as a fun project to cover up the functional-looking fan screen.