Campervan Roof Vent: DIY Installation

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Looking for some helpful advice on how to DIY install a campervan roof vent? Well you’re in the right place!

Getting to the stage of your van conversion where you’re ready to start cutting holes through the sheet metal is intimidating. But nevertheless, a right of passage for any DIY van builder. And the good news is once you’ve done the first one you’ll have lots of confidence for the next ones.

Campervan Roof Vent Installation

In this blog we’ll be detailing the best campervan roof vents and giving an overview of our sprinter van ventilation system. Accompanied by plenty of van roof vent installation tips and also explaining just why campervan ventilation is so important.

campervan roof vent installation

Why Install Campervan Ventilation?

There’s a number of reasons why having a good ventilation system in such a small living space is important. Getting rid of bad smells and temperature control are integral to comfort. But more than that, circulation of fresh air is a must for using a gas cooker and water vapour.

Without campervan ventilation water vapour from cooking, shower steam and breathing will hangaround in the air and cause serious condensation issues leading to mold and rust.

There are various combinations to achieve ventilation in your van build, but all of the best ways undoubtedly include a van conversion roof fan.

Best Van Roof Vent Fan

There are numerous, but to keep it simple I’m just going to compare the top three camper roof vents on the market; Fiamma Turbo Vent, Dometic Fantastic Fan 7350 and MaxxAir MAXXFAN Deluxe.

Each make and model has different features such as an automatic rain sensor, remote control, adjustable speeds and climate control. But they are all electric camper vent fans, because really that’s the only way to go. 

FiammaDometicMaxxAir 
Speed Settings51410
Built in ThermostatYesYesYes
Air Intake & OuttakeYesYesYes
Max. Amp Draw p/h1.83.04.0
Remote ControlNoYesYes
Rain SensorNoYesN/A
Used in RainNoNoYes
Cost££££££

We opted for the MaxxAir MAXXFAN Deluxe 7500K mainly because it can still be operated in the rain. As opposed to the Dometic Fantastic Fan 7350 which just automatically closes and shuts off in the rain. But then needs to be manually turned back on.

Being in the rainy UK, it seemed like a pretty essential feature. We don’t, but if you travel with pets that you intend to leave alone in the van, a van roof vent fan that has both thermostatic climate control and can be operated in the rain is crucial.

You also have the choice of a white (model 7000k) or smoked (model 7500k) lid with the MaxxAir MAXXFAN Deluxe.

Our Van Roof Vent System

In addition to our van conversion vent fan we have another van roof vent, but this isn’t a fan, it’s a rooflight vent. Essentially a window in the roof. But has some small built in vents that can remain open whatever the weather. 

Each is at opposite ends of the van, so we use our MaxxAir fan to expel air and the MaxxAir Skymaxx Rooflight to draw fresh air in. We also have two windows in the living area of our van which draw fresh air in while open.

Van Roof Vent Location

The most common location for van roof vent installation is down the middle of the van. There aren’t many vans, if any, that have completely flat roofs. Most have ribs running lengthways. But you may find as we did with our Mercedes Sprinter that there are some flatter places.

Just be sure to internally check your chosen location too, so that it is free from any cross beams running widthways inside the van. The rest of it really just comes down to preference and whether you are installing one or two van roof vents.

We have our MaxxAir vent fan over our kitchen area and right at the side of our bathroom.

As we have a shower curtain with a gap at the top, we don’t have a separate extractor fan in the bathroom. It’s a powerful van conversion fan so it’s incredibly efficient at both pulling out smells and vapour from both the kitchen and bathroom in the location that it’s in.

MaxxAir MaxxFan Deluxe
MaxxAir SkyMaxx Rooflight

Then our MaxxAir Skymaxx Rooflight is at the opposite end of the van, directly above our bedroom area. It has a built in pull across blind if you prefer to block out light while you sleep and also a bug net. It opens right up, and is brilliant for stargazing from bed.   

Some people opt to put a van roof fan in both the front and back one to draw in air and one to expel air. But just be aware that this means having two fans running off your 12V battery system.

And from experience we can tell you that the power of the MaxxAir Deluxe is more than capable of creating a cooling breeze using the rooflight vent and/or windows to recycle the air.

Van Roof Vent Installation

We’ve broken what we did during our van roof vent installation down into 10 easy to follow steps. It was the same process both the fan and the rooflight.

Van Build Tip: If you’re working outside, pick a day when it isn’t going to rain and allow the entire day so you can take your time and triple check before cutting or drilling.

1. Draw out the cut

Handily most campervan roof fans tend to all be a standard size, but it’s always best to check the measurements for your individual fan in the specific manufacturers installation guide. 

To draw the cut on your roof you’re going to need a ruler and a set square. Double check your corners are all 90 degrees and use a pencil in case you need to redo it.

camper roof vents preparation

For installing maxxair fans, many van builders in the US use these foam gasket adaptors that go between the van roof and the fan but handily double as templates too. At the time of writing this I couldn’t find a supplier in the UK or Europe.

Van Build Tip: Lay some plywood across the roof to rest on so your weight is distributed. Sheet metal bends easily. Luckily the dent we put in ours popped out, but it’s better avoided.

2. Drill starter holes

Tape a bag to the inside of the van ceiling, below where you are about to cut the hole. This will help prevent metal filings falling inside the van. Metal filings = rust. And they get everywhere.

It’s essential to pop some safety goggles on at this stage too. Much worse than rust would be getting a metal filing in your eye.

van conversion metal filings

Drill a whole large enough for your metal jigsaw blade to fit into in each corner. But don’t drill right in the corner. It’s really important that you don’t go over the line and make the hole too big at the corners. You can always use a file to take the very corners out if needed. 

3. Connect the dots

Next tape up the underside of the jigsaw with some thick tape. This is to prevent the jigsaw from scratching the paint on the van roof. Alternatively you can put the tape on the van roof but we found the former easier.

The easiest way to cut out the square is not to make turns, simply cut in straight lines into each corner. Don’t pull your blade out until it has completely stopped.

4. File & treat the bare metal

Now clean up the hole by filing off any rough burs and clean up all the metal filings. A vacuum is very handy. Then treat the bare metal edge with a rust preventative metal paint and allow to dry.

camper vent fan hole

5. Add the internal wooden frame

Best made in advance so it’s ready to fix straight on, the next step we did was to add a wooden frame inside the van roof as support for the van conversion roof vent. 

If you don’t already have a Kreg jig, this is the perfect opportunity to get one because it makes wood joins a cinch and you are going to need one for so many other things during your van build.

We attached it with Sikaflex, a strong flexible adhesive, holding it in place with clamps until set.

van roof vent installation
van conversion roof fan frame

6. Prime metal surface

Once the metal paint is dry, prime the surface of the van where the fan will be attached with a good quality primer. That is to say remove any dirt or grease so that the adhesives you will be applying next can create a watertight seal.

7. Add mastic strip

Next it’s time to add the mastic sealing strip. This stuff is a malleable putty that creates a flexible waterproof seal. If your van roof isn’t flat and ribbed like ours was, you’ll need to build the mastic up in layers to create a flat surface for the flange to attach too.

The flange is just the plastic frame that the fan sits in.

mastic sealing strip

If you are using a foam gasket adaptor you’ll want to stick that directly to the van roof first. Most people use sikaflex or another similar flexible adhesive. The mastic sealing strip will then go in between this and the flange.

8. Screw flange in

Double check the manufacturer instructions for specific camper roof vents to ensure you install the flange facing the right way. For the MaxxAir vent fan the four raised metal tabs on the flange should be to the sides. 

Press it down firmly and mould the mastic tape into any little gaps. It’s easier to check from the inside for any spots of daylight coming through. Then using self tapping screws fix the corners of the flange into place first of all to make sure the alignment is correct.

After that start working your way along the edges, clamping the flange to the van roof through the sheet metal and into the wood frame.  

With regards to the Skymaxx Rooflight we installed, there is another internal piece that clamps the camper roof vent in place. So the screws go in from the outside, there aren’t any visible screw heads on the outside. We still put a wooden frame in between for stability. 

roof vents for motorhomes
campervan roof vent installation

Then the final internal casing with the in built blind and bug net is designed to clip onto this.

Because we have cladding on the ceiling, we however had to pop four pilot holes in each corner of the casing and screw it into the wooden cladding. 

9. Seal all edges

In addition, you’ll now need to seal all the edges and screwheads with a flexible adhesive. We used sikaflex, which is ideal for the job. Put plenty on, leave for a few minutes until it stops being sticky on the outside and then smooth with a wet finger. 

skymaxx rooflight waterproof seal

It’s pretty much impossible to get it 100% neat. But the most important thing is that it is water tight, and no one is ever going to see it up on the roof of your van anyway. 

Have another check from the inside for any daylight you can see coming through where it shouldn’t be. 

10. Install fan 

The next job is to drop the actual fan in. Ensuring that you are fixing it on the correct way with the hinge opening to the front of the van. Then there’s four screws that go through the sides to secure it in place. You might need to press the fan down to be able to get them lined up.

Heading inside now, there’s there the internal trim that needs screwing into place. But you might need to wait to do this until your ceiling is finished. We had to trim a little slither off the side of ours too to fit up against the bathroom doorway. Easy enough with a jigsaw.

camper vent fan

Then the very last step is to get the campervan roof vent fan wired up. If you aren’t at the electrics stage yet, that too might be a job for a later date. 

Van Build Tip: The next day when the sealant has fully set, give your van a good wash down to remove any minuscule leftover metal fillings. It will be worth it in the long run.

Tools, Parts & Materials

Here’s everything we used during our campervan roof vent installation:

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Hit us up in the comments with any further questions you may have about our van roof vent installation and we’ll do our best to help you out.

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