Maxxfan Roof Vent DIY Install on a Van | Step-By-Step Guide

Maxxfan Roof Vent DIY Install on a Van | Step-By-Step Guide

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Installing a roof fan is essential in a campervan. It helps:

  • Regulate the temperature. Makes your van comfortable to live in.
  • Control humidity. Helps prevent condensation and mold.
  • Maintain good air quality. Exchange air and evacuate the smell from cooking.

The Maxxfan is tried-and-true, and the rain shield allows to run the fan when it rains, which is a must. It’s typically one of the first modifications performed on a van, so it’s super intimidating… but you are not alone: it’s a rite of passage for all DIYers! With this guide, you’ll get it right the first time and boost your confidence for the subsequent steps of your van conversion. Let’s get to work!

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6 hours


$460 USD


20 lbs


Maxxfan Deluxe15100K (White lid, manual opening)Amazon | Campervan-HQ
6200K (Smoke lid, manual opening)Amazon | Campervan-HQ
7000K (White lid, auto opening)Amazon | Campervan-HQ
7500K (Smoke lid, auto opening)Amazon | Campervan-HQ
Roof Vent Adapter1Select your van model in the listing (Transit, Sprinter, ProMaster, etc.)eBay
Dicor Self-Leveling Lap Sealant2WhiteAmazon
Sikaflex 2211Polyurethane sealant (between van and adapter)Amazon
Butyl Tape (1-inch wide)1Between the fan flange and the adapterAmazon
Machine Screws16#10-24 thread, length TBD*, Stainless Steel, Round HeadAmazon
Nuts16#10-24, Stainless SteelAmazon
Washers32#10, Stainless SteelAmazon
Protective Enamel Spray Paint1To touch up bare metal and prevent rustAmazon

*The length of the machine screws required varies with installation (van model, interior adapter or not, etc.), so we can’t possibly make a one-size-fits-all recommendation. In our van (Ford Transit with the fan installed in the most forward bay, using the adapter on the outside only), we used 1″ screws on the front/back edges and 1-1/4″ screws on the left/right edges.


Caulking GunTo apply sealant to adapterAmazon
JigsawTo make fan cutoutAmazon
Blades for Jig SawThin metal cutting bladesAmazon
Scotch-Brite PadTo prepare surfaces for adhesiveAmazon
Metal FileTo break the sharp edgesAmazon
SandpaperSurface preparation before touch-upAmazon
ClampsTo hold everything in place
Painter Tape To mark cut line and protectAmazon
Isopropyl Alcohol To prepare surfacesAmazon

Good To Know

Maxxfan Models and features

Rain shield

All the DELUXE models feature an integrated rain shield, meaning the lid can always remain open, even when it rains. Neat! That’s a significant advantage over the competitors… As we all know, ventilation is crucial, but it’s even more important when it rains and humidity is high!


The 5301K & 6401K Maxxfan models feature only 4 speeds, cannot be run as intake, and don’t have an “automatic” mode. For these reasons (but mostly because there are only 4 speeds), we wouldn’t really recommend it.

Electric opening & remote

The 7000K and 7500K Maxxfan models feature an electric lid opening and remote (the 5100K and 6200K models must be opened manually). We personally have the manual lid opening because we worried that the electric opening might have trouble in snow or ice. We also don’t have the remote because we’re always at an arm-length distance from the fan anyway!

White vs smoke lid

At last, you have the choice between a white lid or a smoke (grey) lid… that depends mostly on personal taste and your van’s color!


Maxxfan Current draw:

Here is the actual Maxxfan current draw in our 12V system:


Do not use a grinder!

Using a grinder to cut the fan cutout is pretty badass. But all these cool sparks are actually metal chips going all over the place, and each one of them is a potential ignition point for rust! These tiny chips stick to the van and it’s just impossible to clean them afterward, so DO NOT USE A GRINDER.

grinder metal chips rust
Pretty sure this guy is rocking a beard.

Where to install: Back or front?


Most people choose to install their fan in the back of the van, as this creates an airflow that runs through the entire van: air enters through the front door windows and exits through the fan in the back.

We think it’s an ideal location, except if you’re in a similar situation as us (keep reading “FRONT”!).


Cooking with the doors open during skiing season is not an option. Therefore, we installed our roof fan above the stove/oven ( That way, the smoke and smell are evacuated immediately.

But there is a drawback: air in the back of the van is not well recycled. To compensate, we should have added a window in the back (

Back AND front!

We see many people with two fans on their vans: one in the front and one in the back. Typically, one fan acts as the intake (OFF), and the other fan acts as the exhaust (ON).

People with this setup are really happy about it as it creates excellent ventilation. It’s cheaper (and easier) to install a second fan than a window, but the drawback is that it uses more real estate on the roof. If you plan on adding a patio on your roof, that might be an issue.

Add Support Framing or not?

You can add support framing to distribute the fan’s weight to the adjacent frames. That would be necessary for an air conditioner unit (heavy!) or installing the fan where the frames are farther apart (large unsupported area).

We didn’t use support frames in FarOutVan #1, with the fan installed at the same location, and had no issues. So, we are skipping the support frames again, and we feel our installation is solid.

Support framing to distribute the weight to the adjacent frames. Buy on eBay.


Lesson learned
from Far Out Van #1

We didn’t have a Flatline Roof Rack on FarOutVan #1 and made the cutout from inside the van. Don’t do this! Metal chips will fall in your eyes and hair, and they’re dangerous and very hard to remove. Also, it’s awkward and hard to make a clean cut. The roof rack makes it easier to work from the top!

1. Make a 14″ x 14″ cutout in the roof

Find the location for your Maxxfan. Left/right is easy: the adapter fits neatly into the indentations of the roof. For front/back, we centered ours between the frame and the edge of the recess at the front (this edge is visible outside as well, use it as a reference):

Apply painter’s tape over the trim line and a few inches beyond the adapter perimeter (2 layers thick because the jigsaw can rip through the tape easily and scratch the paint). Use the interior of the fan adapter to mark the contour of the 14″x14″ cutout:

Tape a box to the ceiling to catch the metal chips (our box eventually fell… use more tape or straps!):

Drill a hole at each corner, tangent to the contour lines, large enough for the jigsaw blade (1/8″ drill bit, and then we used a 3/8″ drill bit):

Using a jigsaw (or a nibbler), trim along the contour line (tip: before cutting the last edge, tape the other edges to prevent the panel from falling for a cleaner cut):

The jigsaw spits out a lot of metal chips all over the place! Remove them immediately, and keep the area clean to prevent scratching the paint and the chips from getting stuck into the adapter. So keep a vacuum close. You can also use some tape to stick the metal chips to it and peel to remove them.

2. Drill all 16 holes around the flange periphery

Install the adapter and the flange, then clamp to ensure nothing moves. Drill all 16 holes with a 13/64″ drill bit through the adapter and the roof, using the flange as a template

  • Locate the flange so the metal inserts (used to secure the fan) are left/right.
  • Our box fell off, so we installed a plastic bag instead…

Remove the adapter and the flange (they will have to be reinstalled in the same orientation for the holes to match perfectly, mark the front and rear!), then enlarge all holes in the roof (not in the adapter) with a 7/32″ drill bit (this will make the assembly easier subsequently) :

3. rust prevention

Lesson learned
Not our van, but still relevant!

Steel -which is the material your van is made of- corrodes (rust) in the presence of moisture and oxygen and the damage done to its structural properties is irreversible. Any steel left “bare” after cutting or drilling is a potential starting point for rust.

The best protection against rust is a multilayer coating system: primer, paint, and topcoat. This system seals the metal from moisture and oxygen and provides a hard surface to protect against abrasion and UV. Proper curing is required between each coat, so follow manufacturer recommendations.

It is also acceptable to use 2 layers of rust-preventative paint, per the Material section above.

Deburr the edges with a deburring tool and a file, then smooth with 220-grit sanding paper (this promotes the paint’s adhesion).

Tip! To deburr the holes, it is easier and faster to use a large drill bit (e.g., 3/8″) or a countersink bit (use light pressure and just a few turns):

Apply painter’s tape around the perimeter of the flange (leave 1/4″ gap):

De-gloss the mating surface (adapter with roof) with a Scotch-Brite pad (see Tools section). No need to scuff, just dull the paint:

Clean the mating surface and the edges (contour and holes) with Isopropyl alcohol:

Apply 2 coats of rust preventive paint (let dry between each coat, follow product instructions):

4. Prepare the surfaces for the adhesives

Use isopropyl alcohol to clean the roof where it will mate with the adapter:

Clean the Maxxfan flange with isopropyl alcohol:

5. Apply the sticky stuff

Apply the butyl tape around the Maxxfan flange perimeter, make sure to apply over the holes:

Apply 2 or 3 beads of Sikaflex 221 to the surface of the adapter mating with the roof:

6. Install the adapter and the flange

Start by installing the adapter:

Then install the fan flange:

From the top, insert the screws and washers (poke the screws through the butyl tape). From the bottom, install the washers and nyloc nuts. Fasten all the nuts uniformly, but do not over-tighten! If there is too much pressure, the flange could eventually crack. The goal is to have a tight fit and have some oozing, but don’t go crazy:

The butyl tape and Sikaflex will ooze out a bit, which is a good thing. Trim the extra butyl tape, and use your finger to make a fillet around the Sikaflex (as required):

We didn’t get as much Sikaflex oozing as we wished, so we added a little to make a nice fillet around the perimeter:

Remove the painter’s tape within 15 minutes and let the Sikaflex form a skin for an hour:

7. Apply the Dicor self-leveling sealant

Apply Dicor self-leveling sealant. Ensure to cover the flange, the screws, the adapter, and the roof. One cartridge of Dicor is barely enough, so make sure to have a second one handy just in case:

Heck that was hard work, so treat yourself while you wait for the sealant to cure for a few hours!

8. Install the Maxxfan

Slide the Maxxfan over the flange:

Install the 2 screws on each side, remove the protective film, and be happy!

Isabelle remove protective film

Get in the van, yep there’s a fan!

9. Electrical

We still haven’t installed our electrical system at the time of writing these lines, so that part has to wait. But the Maxxfan will be wired per our wiring diagram:

On Second Thought

We also installed a Maxxfan on FarOutVan #1 back in 2017. To this day, Maxxfan is still the reference. The dome (rain shield) is a must; it allows to run the fan even when it rains (which is much needed!).

But they’re not perfect either. If you look online, you will see that some people have issues with rattling (you can order an anti-rattling kit) and the motherboard (condensation and/or overvoltage can short the motherboard and then must be replaced. Kit available, contact the company). We had to replace the motherboard on our first Maxxfan, back in 2018, because our solar controller (Bogart) was outputting too much voltage (over 16V) and most likely shorted the motherboard. We have since then upgraded to a Victron solar controller, and it’s been working perfectly fine. Note that some people strongly recommend installing a 12V voltage regulator for the Maxxfan. We personally did NOT install a voltage regulator after the incident, and it’s been working fine without it.

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About us



Hello! We’re Isabelle and Antoine 🙂 In 2017, we sold our house (and everything in it), quit our engineering careers, and moved into our self-built campervan. Every day is an opportunity for a new adventure... We’re chasing our dreams, and hopefully it inspires others to do the same!

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Thanks to all of you, we managed to negociate group discount on these. Strength in numbers!

2 thoughts on “Maxxfan Roof Vent DIY Install on a Van | Step-By-Step Guide”

  1. Started installing my fan today and was wondering about using washers. Thanks for the update and the convenient timing!


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