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How to: fit a campervan skylight


When you decide to fit a campervan skylight, you can pay someone to install it for you, or you can commit to doing it yourself. After getting quotes for how much it would cost to have someone else install our windows and skylight, we took the plunge ourselves and committed to cutting some holes in the side of our van.

The primary reason we decided to install a skylight in the van was because we want to make sure that it will be as light as possible inside. As well as this, it will also provide additional ventilation whilst cooking, and will allow more air into the van on warm nights.

We bought the Dometic Seitz Mini Heki, which comes with a built in fly net and blind. We opted to not go for a skylight with a built-in fan, as we’re going to install two roof vents at either end of the van which will be powered, so that one can draw air in and one can draw air out (this will help with airflow and decrease condensation). 

As with the windows, professional van builders will use a nibbler tool or a pair of electric shears to cut through sheet metal. We watched some YouTube videos on how to install a skylight and windows with the tools we already owned, to save money on buying new tools.

man installing a Dometic skylight on a Sprinter van conversion campervan

Drilling and cutting the hole

First, we laid everything out on the roof, to work out where everything would go. This included our three solar panels, two vents and the skylight. Once we were happy with positioning, we set to work on cutting the hole for the skylight.
Installing the skylight was much easier than the windows, as it’s a square, so you only need to cut four straight lines instead of the curved profile of the windows. 
We started by drilling four pilot holes, and then widened the holes to 24mm using a step drill bit. You would usually do this job with a hole saw, but we didn’t have one of these and the step drill bit did the job fine.
man drilling a hole in a yellow Sprinter van conversion campervan to install a skylight

Once the four holes were drilled, we joined the dots with the Jigsaw. I think Dale is pretty happy that the Jigsawing jobs are almost over! It’s definitely the noisiest job, and as we don’t have a nibbler it’s seen quite a lot of action. Luckily it didn’t need to be out for very long, as it was quite a quick process cutting straight lines between the four holes.

When we cut the van windows in we put masking tape all around the outside of where we would be cutting to avoid marking the van with the Jigsaw. This time we just put gaffer tape on the Jigsaw itself and this had the same effect, and saves time and tape (thanks Pete!).

Filing and painting the edges

As we haven’t been using a nibbler which leaves a clean edge, each time we’ve chopped a hole in the van using the Jigsaw we’ve needed to file the edges down so that they’re smooth. Filing creates a more even and level surface, which improves the chances of creating a reliable seal. We then applied Hammerite to the edge to reduce the risk of anything rusting.

girl in geometric jumper painting Hammerite onto a Sprinter van conversion in order to install a skylight

Levelling the roof

As the top of the van isn’t flat, we used mastic tape to create a level surface to adhere to. This is super important as if the surface that you’re attaching to isn’t level, 1) you’ll struggle to adhere in the first place as you won’t have many points of contact, and 2) you’ll end up getting water ingress. Mastic tape kind of feels like a cross between Blu Tack and play-doh, so it’s great for moulding into whatever shape you need. We added a few strips of mastic until the edge was completely level to make sure water wouldn’t have a path to get in.


Attaching the skylight

Once the mastic tape was on, we used a sealant called Sikaflex EBT to stick the skylight to the mastic. This is an all weather sealant so is perfect for preventing leaks, and it’s what most people use for this kind of job. 

To be extra safe (can you tell we were worried about leaks?!), we then applied a layer of Dicht-Fix all around the skylight and mastic tape. This is a gluey grey paint reinforced with carbon fibres, so in case of any gaps between the skylight, the mastic and the van, everything is completely sealed. Applying the Dicht-Fix gave us a lot of confidence that everything we covered in it would be sealed, as it forms a really thick, reinforced layer over everything painted.

man applying Mastic tape to a van conversion in order to install a skylight

Once the skylight was installed on the roof, the frame which the fly net and blind sit on could be attached to the inside using some metal clips. Where we chose to install the skylight meant that we had to cut the plastic frame in order for it to fit. We trimmed the edges off with a circular saw, but as we’re cladding the inside of the van, we’ll make a frame for the skylight so this won’t be visible.

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25 Responses

  1. hello, I see the skylight comes in two different roof depths: 25-40mm and 40-60mm. which one have you find better fitting for your conversion? thx

    1. Hey Andre,
      We picked the 40-60mm deep skylights as we tried to fit ~50mm of insulation in the roof of the van. As heat rises, you can expect to see a 40% temperature difference between the top and bottom of the van so we tried to pack as much insulation in the ceiling as possible. Hope that helps!

  2. Hello, I was just wondering about the width of the mastic tape you used. The link in your article takes you to the 19mm one, was this wide enough?
    Thanks in advance!

  3. Hello, how effective do you find your two 12v mushroom roof vents when it’s warm? Some sites say they may not be effective for the LWB vans. Do you wish you had got something like a powered roof vent instead (expensive!) or are you happy with your setup? Cheers!

    1. Hi Sean, they’re less for cooling down the inside of the van, and more for promoting air circulation. For example, if you’re cooking in winter, turning them on will help to prevent condensation. If you want to physically feel cooler, you would be better getting something like the MaxxAir van. But to be honest, we find just opening the door for a bit is enough to bring down the temperature of the van! We wouldn’t bother with a powered roof vent in another van. Hope that helps!

      1. Hey, thanks for the all the info – when you say you wouldn’t bother with a powered roof vent, do you also mean the mini computer vans that you installed or just the MaxxAir one you referenced in this comment? We are just at the start of the conversion planning stage 🙂

        1. Hi Elliot, we’re glad you’ve found it useful! Personally in another van we wouldn’t bother with a powered roof vent such as the MaxxAir as like above we do find just opening the door for a bit is enough to bring down the temperature of the van.

          Ultimately it would depend on your requirements and what climates you plan on travelling to, I hope this helps!

  4. Hi there,
    I saw in one of the questions you mentioned that you chose the depth of the skylight because of the insulation you used. Did you install the skylight before the insulation? Or was the van already insulated? Which way round would you recommend? Thanks.

    1. Hi Jon, it’s definitely best to install all external components to the van first and then insulate. Most skylights will need an internal frame to be built around the aperture (hole in the roof) so the skylight can be clamped to the roof. The Dometic instruction manuals are pretty good at describing and illustrating the process, so it might be worth checking those out 🙂

      1. Hi. Thanks so much for this advice. I was about to make a big mistake! Was hoping to insulate now then add the skylight next year when the budget allowed. I guess I’ll just take the plunge right away. Thanks for your help and your excellent site!

        1. Hi Jon, much easier to get all external bits installed before you insulate, makes the job so much easier! Good luck with the skylight install and the conversion 🙂

  5. Hi Charlie and Dale,
    I was hoping to have around 100mm of insulation on the ceiling, but I can only find skylights that fit to a roof depth of around 60mm. Is there a way to extend the depth or frame over the interior plastic frame, or should I cut back on the ceiling insulation?
    Many thanks,

  6. Hi,

    I’m definitely hoping to get your guide for Christmas this year – looks excellent. Do you have any advice on whether you can add a skylight to a used bought converted van that’s already been insulated? Anything different to consider as part of the process?

    Many thanks,

    1. Hi Stephen, thanks for your message. It’s definitely possible to retrofit a skylight, it’s just a bit more faffy as you will likely need to remove the ceiling cladding and insulation around the area before cutting the hole in the van. So perfectly possible, it just won’t quite be as quick as if you were doing it from scratch. Make sure you think about where it’s going to enter on the inside, there could be wires etc under the cladding which you will need to be careful to avoid. Hope that helps!

  7. Can you put a skylight where the ribs or roof struts are?
    I want to put one over my bed so I can see the stars at night, but it looks like there could be a join where I want it and I think there is also a roof strut crossing over the spot I want the hole.

    Van is second hand and I’m pretty sure it isn’t insulated so I’m up for removing all paneling to sort that out.

    1. Hi Scott,

      The ribs in the roof are structural. So they can be cut as you would when fitting a poptop, but would need a reinforcing frame fixed to the roof to stop it moving. If you don’t do this it is likely to leak, or worse be unsafe in a crash. There are many size skylights, so you’re probably better off finding one that fits between the ribs in the roof if you can!

  8. Dear Charlie and Dale,

    I have ended up in a rabbit hole of ventilation… I am also wanting to install two 12V electric roof vents however the options I am finding online are pretty poor.

    I can see from this posts pictures you have installed a black mushroom vent. Would you please be able to provide me with details of the vent and extract fan


    1. Hi Sam,

      Unfortunately we don’t remember exactly which vents we used but we installed two computer fans which can be controlled via two switches, one which draws air in and one which sucks it out.

      We hope this helps!

  9. Hey guys,

    Thanks for all of the super helpful information. We are just about to install our Dometic Mini Skylight and MaxxAir fans and I keep seeing contradicting information. Some people don’t mention a wooden frame while many other videos explicitly state the need for a wooden frame to sit on the underside of the roof panel that the skylight attaches to. I can’t see you mention it in your book or on this article so I’m inclined to do as you guys have done. Is it the case that you don’t have a wooden frame your skylight is screwed into?


    1. Hi Elliot, most skylights will need an internal frame to be built around the aperture (hole in the roof) so the skylight can be clamped/screwed to the roof. This can also make it easier when installing the ceiling as it gives you another surface to attach that to. The instruction manuals are pretty good at describing and illustrating the process, so it might be worth checking those out 🙂

  10. Have your book and love it!
    With the mushroom vents, one for ‘in’ and one for ‘out’. How did you sort this?
    Buy two of the same and flip the blades on one to reverse the direction?
    Cant seem to find any suppliers who specify the direction of airflow.

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