Mounting a Fan/Vent in Campervan Pop-up Roof

For anyone interested in adding a vent or indeed a fan / vent to a pop-top roof

After a very hot June in 2025 travelling through Italy in our VW Campervan, we had the idea of installing a roof vent with a fan. We eventually found a couple that can be run even when it's raining (important in the UK). Bingo!

We opted for the Nomadic Ark AirPlus in Black with a clear dome. There is another similar by MaxxFan, which many love, but you have to pay extra for a blind and lights and we couldn't find an all black version.

I started searching for anyone that had mounted one in a 'pop-top' roof, but it seems that either nobody has or never documented it and I started to wonder if there was a reason not to do it. would it weaken or be too heavy for the roof to stay up on it's own? Would it all end horribly. I posted a question on one of the forums I belong to (Pop-top roof vent/fan installation | VW T6 Transporter Forum), which drummed up some support but no-one had attempted it there, nor any of the others I belong to. So with some optimism, I bit the bullet and bought the fan. We opted for the black version as our roof is black too so it won't look out of place. It sat in my office for a month or so as I wanted to wait for better weather and a long weekend to ensure I had time to get it completed, (Woody, that's the vans name, is also my daily driver), as I couldn't be without wheels. In the UK we get a long weekend at Easter, both the Friday before and the Monday after are bank/public holidays. Ideal!

What you'll need, (in no specific order)

    

    

For safety when working with fibreglass, good goggles, gloves and face mask are essential. As too will be a sturdy working platform, you don't really want to be sitting on the roof when you do this.

Once the above is sorted, you'll need amongst other things, a good jigsaw and drill (cordless are better for this than corded), I also bought a jigsaw blade for cutting carbon fibre, but not entirely necessary. Some fibreglass workers say to use an angle grinder/circular saw, but that would have been messy.
Other things you'll need are (I'll not give any links as you'll already know where to get them if not Amazon);

• A vacuum cleaner or dust extraction of some sort hooked up to your jigsaw/cutter. Remarkably, there wasn't all that much dust, which I put down to the CF blade.
• Plywood: at least enough for 30-50mm larger all round than the hole you'll be cutting, I chose 18mm thick as it is strong and offers good purchase depth for screws.
• Cable for the power 2 x 1mm is ample but I'm no electrician, so you may want to check.
• Some quick connectors, crimps and crimpers.
• A good sharp knife and scissors.
• Material to match or contrast with your headlining, if you already had some in place.
• Sikaflex 522 and sealant 'gun'.
• Butyl tape for sticking and sealing.
• Duct or Gorilla tape.
• Screws long enough for your needs, (more on that later).
• Tape measure and straight-edge for marking.
• Pencil and suitable pen or chinagraph/grease pencil for marking.
• Screwdrivers, pliers, sandpaper, files, etc.
• A good friend to lend a hand and offer advice, when you get stuck or unsure. Or to drive you to the nearest hardware store, if needed.
• Time, light and patience. (Do it right first time).

Step 1: Preparation

• Marking and preparing the area you'll be cutting is essential. Also, knowing how thick the roof is where you'll be cutting, will help your screw selection...
• I measured the fibreglass at the front of the roof at 6mm and with the 3mm step up to the area where I wanted to cut, came up with 9mm. I added another 3mm for the thickness of the mounting frame, and bought a pack of 25mm black wafer-head screws, as the ones supplied were steel dome-heads...
• Wrong choice! What I should have done and recommend anyone else do, drill a pilot-hole in the centre of the cut-out, take a measurement of the thickness at the point you'll be cutting it, plug it and then purchase the correct screws.
• The roof was 20mm thick at the point I'd be cutting, due to various fillers and insulators, so I needed 40-42mm screws to be in with a chance of getting any purchase on the inner plywood frame. (3mm mounting frame, 2mm Butyl tape, 20mm roof, 1 mm Butyl tape = 26mm, so no way to get the originals to bite). Luckily, my friend and helper, didn't mind a trip to the local hardware store, where I could get more suitable ones.
• Using your plywood frame as a template for cutting mark the hole and frame on the roof / headlining, I used a normal pencil for this as it wouldn't take much to remove it once finished.
• Be sure to cut away the headlining if you already have some in place, as when you drill or start to saw through, it'll snag on the bit or blade and all sorts of damage can be done. With my installation, I left approx 10mm of headlining inside the marked area where the plywood inner frame would be sitting. This meant the material wouldn't drop or fray over time if there wasn't enough adhesive on it. and the plywood frame would sink into it nicely.
• Using your plywood frame as a template again, mark the hole on the exterior using whichever pen or pencil works best for you.

Step 2: Cutting the Hole

• Attaching the box the vent came in to the underside of the roof with tape proved unreliable, so we rigged up the 'bed ladder' as an 'Acroprop', but still made use of the tape... (should have used Duct or Gorilla).

• I marked up the centres for the 13mm spade bit that I'd be using to drill the entry holes for the jigsaw and then bored one hole in each corner. You could use two holes diagonally opposite each other too.

• Carefully staying just within the marked lines, cut the hole with your jigsaw or cutter of choice. If you cut it too small you can always file or trim the excess back.
  

      
• As you make the final cut, the excess should fall away into the box you placed earlier.
  
• Check for fit and trim as necessary.

Step 3: Securing the Mounting Frame and Finishing the Top Installation

• Once you've made the hole fit the mounting frame, mark the screw holes. I used a Marksman chalk marker tool, but you can use anything you prefer to do the job.

• Carefully drill your pilot holes, I used a 3mm HSS bit as the screws were 4 x 40mm.

• Apply the Butyl tape. I used 2 layers, but could have easily gotten away with one, and would recommend that to anyone else fitting the Nomadic Ark model, as 2 layers seemed to make the frame distort slightly.

• Run a bead of Sikaflex 522 all round the inner edges of the hole to prevent any moisture from getting into the fibreglass and foam plies. It's crap to work with, but does a fantastic job!

• Get the interior plywood frame in place. This is where your friend is essential; it doesn't matter how strong you are or how well you think you may have aligned it, a second pair of eyes will be essential as well as pushing against you whilst you screw the frames together.
• Clear up the Sikaflex as best you can, there will likely be loads of it that's oozed out, but as above, better than too little.
• Now you can attach the top/main part of the unit. If everything went well in the previous steps, the screw holes will align and you can whizz em in and move to the interior fitting. If not, make any adjustments and if the threaded plates need to be re-aligned, use a longer screw or thin screwdriver to help position them.

Step 4: Completing the Interior

With everything finished on top of the roof, it's time to turn our attention to the inside installation. Most of this is less of a challenge as there are only 4 screws required to fit the control panel to the plywood frame. The wiring isn't too tricky either as it only requires a +12V & -VE supply. I'll leave you to deicide where you get yours from, but mine comes from a 10A fused connector on the interior electric control panel at the back of the van, so I ran a 2x1mm cable from there to just inside the cut-out for the vent with a quick connector. I 'channelled' it under the original headlining rather than cutting it in. To do this, I inserted a 3mm drill-bit into a length of Teflon tubing I have spare from my 3d printer supplies, made a small nick in the headlining at the corner of the plywood frame and carefully at first twisted it under the first few centimetres, then with the other end in my cordless drill started feeding it sideways to the edge of the roof where the canvas is joined and then fed the cable through. I then cropped the original cable from the control panel so as there wasn't so much slack and crimped the female quick connector to that. The rest is just fitting the control panel to the roof after covering the plywood.

So a quick step by step:

• Identify your power source.
• Run your cable from there to the vent.
• Attach connector of choice.
• Cover the plywood with your preferred material. (I chose the same faux suede material but in a contrasting shade as getting an exact match would have been hard).
• Connect all cables.
• Offer the panel up ensuring the manual lift rod engages.
• Screw in place.
• Cover the lights with their caps.
• Enjoy.

                          

Now it's all done and dusted, I'm pleased with the result and I haven't noticed much difference in wind noise whilst driving.

What Would I Do Differently

As there were no previous examples of one being fitted to a pop-top, I wasn't sure what I'd come up against. I've tried to highlight all my mistakes, where I could, but here's a list of things I'd do differently or change.

• Make a pilot hole in the centre of the piece of roof you'll be cutting out. This will give you a true measurement of the thickness of the material and allow you to purchase the correct screws.
• Keep the gloves on or keep swapping them for new ones as you work. As you can see from some of the photos, I didn't and the Sikaflex got all over my hands and then transferred to the plywood.
• Purchase the headlining material well in advance, so it can be applied to the plywood frame before it's screwed in place from the top. Or, don't apply the Butyl tape to the plywood until you are ready for the final fix. It's a right pain to cover after the fact!

Our Secure Platform

Somewhere between an Amarok and a hard place

Don't tell Health and Safety!

Good luck if you take this on yourself.