Updated: 23 September 2026 · EuroVan Shop
In short: To fit a campervan window, mark the cut-out, cut it with a jigsaw, fit a wooden batten frame (25 mm minimum) inside, bed the window in Sikaflex 265 and screw the aluminium counter-frame from inside so it clamps the wall. With a EuroVan window it takes about one hour and two people. On a caravan or motorhome, you reuse the existing cut-out.
Choose your campervan windowHow do you fit a campervan window?
You fit a campervan window in eight steps: position, mark, cut, build the batten frame, prepare and seal, clamp the counter-frame, finish the inside and test for leaks. No welding and no specialist tools are needed: a jigsaw, a cordless drill/driver and a tube of Sikaflex 265 do the job.
This guide follows the method for our EuroVan campervan windows. It applies to push-out and sliding models alike, on a Sprinter, Crafter, Ducato, Transit, Master or any other panel van, and to flat motorhome and caravan walls.
How does the window hold in the wall?
The window is clamped, not welded: the window sits on the outside of the wall, the aluminium counter-frame sits on the inside, and the screws pull the two together. The wall and the wooden batten frame are held between them like a sandwich.
Sikaflex 265 does the rest. It bonds the window frame to the bodywork and seals it against water. On the curved side wall of a panel van, the small gap between a flat window and the curve is taken up by the Sikaflex. The counter-frame works on walls from 25 to 75 mm thick, and longer screws extend that range.
What tools and materials do you need?
You need a jigsaw, a cordless drill/driver, a 25 mm wooden batten frame and one tube of Sikaflex 265 per window. Everything else comes in the box: the window, the reinforced aluminium counter-frame, the interior frame with blind and mosquito net, the screws and the fitting instructions.
| Item | What it is for | Supplied with the window? |
|---|---|---|
| Jigsaw with a metal blade | Cutting the opening in the panel | No |
| Cordless drill/driver | Starter holes and screwing the counter-frame | No |
| Wooden battens, 25 mm minimum | Building up a thin van panel so the counter-frame can clamp | No |
| Sikaflex 265 (1 tube per window) | Bonding and sealing the window | No, but it is in our Sikaflex Window Kit |
| Sika Aktivator 205 and Primer 507 | Preparing metal and painted surfaces | In the Sikaflex Window Kit |
| Cartridge gun, lint-free cloth, brush | Applying the 265, the 205 and the 507 | No |
| Masking tape, marker, anti-rust paint | Marking the cut-out and protecting the cut edges | No |
| Counter-frame, screws, interior frame | Clamping the window and finishing the inside | Yes |
Sikaflex Window Kit
Sikaflex 265 + Aktivator 205 + Primer 507: everything to bond one window.
Sikaflex 265 black, 300 ml
Polyurethane adhesive sealant for windows. One tube per window.
Step 1: Where should the window go?
Put the window where its cut-out fits in the free area of the panel, between the ribs. Hold the cut-out dimensions up against the wall from inside: if no rib, reinforcement, cable or conduit crosses that area, the window fits.
As a guide, the largest side cut-out is 700 × 400 mm on an L1H1 van, 970 × 520 mm on an L2H2 and 1100 × 550 mm on an L3H3 or L4H3. In the rear doors, allow up to 500 × 350 mm (L1H1), 500 × 450 mm (Master, Movano, NV400) or 500 × 520 mm (Ducato, Jumper, Boxer, Sprinter, Crafter). These maximums are indicative, so always measure your own panel. Our window size guide helps you plan the layout.
Step 2: How do you mark the cut-out?
Mark exactly the size in the window's name: a 700 × 400 window needs an opening 700 mm wide and 400 mm high. Do not mark the outside of the frame. The exterior frame is 30 mm larger on each axis and covers the edge of the cut, and the interior frame sits proud of the wall, so neither needs extra room.
Cover the area with masking tape to protect the paint, then draw the rectangle on it. Check that it is level and measure it from a fixed reference point, so you can copy the same position on the other side of the van.
Step 3: How do you cut the opening?
Drill a starter hole inside each corner, then cut along the line with a jigsaw and a metal blade. Tape the jigsaw's base plate so it does not scratch the paint. Once three sides are cut the panel becomes loose, so ask your helper to hold the offcut.
Remove the burrs with a file, then paint the bare metal edges with anti-rust paint so the cut cannot corrode.
Step 4: Why do you need a 25 mm batten frame?
A wooden batten frame gives the counter-frame something to clamp against. A bare van panel is far thinner than the 25 to 75 mm wall the counter-frame is designed for, so you build it up with wooden battens or a wooden frame at least 25 mm thick, following the edge of the opening on the inside.
On a motorhome or caravan wall that is already 25 to 75 mm thick, you do not need a batten frame. On a wall thicker than 75 mm, use longer screws.
Step 5: How do you prepare and seal the window?
Clean and degrease the bodywork around the opening, prepare it with the Sika products, then run a continuous bead of Sikaflex 265 on the window frame. Dry-fit the window first to check it drops into the opening without catching.
- Wipe Sika Aktivator 205 onto the metal or painted surface around the cut-out with a clean, lint-free cloth.
- Apply SikaPrimer 507 with a brush where the surface requires it.
- Respect the flash-off times given in Sika's instructions.
- Lay an unbroken bead of Sikaflex 265 all round the contact face of the window frame: a gap in the bead is a future leak.
Sikaflex 265 bonds directly to glass without primer. The Aktivator and Primer are for the metal, plastic and painted surfaces around it. Not sure which product to use? Read which Sikaflex to choose.
Step 6: How do you fit the counter-frame?
One person holds the window in the opening from outside while the other fits the aluminium counter-frame from inside and screws it. That is why the job needs two people.
Start every screw by hand, then work steadily round the frame, tightening a little at a time so the pressure builds evenly on all sides instead of pulling hard on one corner. Use the screws supplied; only change them for longer ones on a wall thicker than 75 mm.
Step 7: How do you finish the inside?
Wipe off the excess Sikaflex outside before it cures, then fit the interior frame with its blackout blind and mosquito net. It covers the edge of the cut-out and the lining, and needs no extra room.
Fitting the VanLight window only? It comes with its counter-frame but no interior frame, so you trim the opening yourself. You can add our inner frame with blind and mosquito net later: order the same size as the window's cut-out. It fits with four screws, one in each corner, into the lining or a light wooden batten.
Inner frame with blind and mosquito net
Pleated blackout blind and mosquito net in one frame, white. Fits walls 24-74 mm.
Step 8: How do you check the window is watertight?
Let the Sikaflex cure for the time stated by Sika, then run a hose over the closed window while someone watches the inside. Do not wash the van or drive in heavy rain before the curing time is up.
If water gets in, find the exact spot, dry it and add Sikaflex at that point of the joint. Test again until the inside stays completely dry.
How do you replace a caravan or motorhome window?
On a caravan or motorhome you keep the existing opening: remove the old window, clean the cut-out and fit a EuroVan window of the same cut-out size. EuroVan windows, except the VanCurve made for curved van walls, fit flat walls from 25 to 75 mm thick.
- Unscrew the interior frame and the old window, and lift it out.
- Remove every trace of old sealant from the bodywork, then clean and degrease it.
- Measure the cut-out itself (width × height), not the visible frame of the old window.
- Choose the same cut-out size: the new exterior frame is 30 mm larger on each axis and covers the old edge.
- Follow steps 5 to 8 above. No batten frame is needed on a 25 to 75 mm wall.
See our caravan and motorhome replacement windows. Changing a roof light at the same time? Our roof windows exist in the standard 400 × 400, 700 × 500 and 960 × 655 mm cut-outs.
VanSlide+
Double-glazed sliding window, flush with the body. Up to 1100 × 550 mm.
See caravan replacement windows
Which mistakes should you avoid?
Most problems come from the preparation, not the window. Avoid these:
- Marking the exterior size instead of the cut-out size: the hole ends up 30 mm too big.
- Cutting through a rib: choose a size that fits the free panel area instead.
- Leaving bare metal edges: paint them with anti-rust paint.
- Skipping the batten frame on a panel van: the counter-frame needs 25 mm minimum to clamp.
- A broken bead of Sikaflex or a dirty, greasy surface.
- Tightening one corner hard before the others: tighten evenly all round.
Stuck at any stage? Our technical team answers during the installation: contact us.
Not sure which size fits your panel?
Send us a photo of your van or caravan wall with its measurements. Our France-based technical team answers within 24 hours.
Ask our technical teamFrequently asked questions
How long does it take to fit a campervan window?
About one hour per EuroVan window for the fitting itself. Plan for two people: one holds the window from outside while the other screws the counter-frame from inside.
Which Sikaflex do I need to fit a campervan window?
Sikaflex 265, one tube per window. For metal and painted surfaces, prepare them with Sika Aktivator 205 and Primer 507, all three of which come together in our Sikaflex Window Kit.
Do I need a wooden frame behind the window?
On a panel van, yes: a wooden batten frame at least 25 mm thick, because the counter-frame clamps walls from 25 to 75 mm. On a motorhome or caravan wall already in that range, you do not need one.
Can I fit a flat window on the curved wall of a van?
Yes. The reinforced aluminium counter-frame works on curved and flat walls, and the small gap on a curved wall is taken up by the Sikaflex. The VanCurve is the model made to follow the curve.
What size hole do I cut for a 700 x 400 window?
Exactly 700 mm wide and 400 mm high. The size in the name is the cut-out size; the exterior frame is 30 mm larger on each axis and covers the edge.
Can I replace a caravan window with a EuroVan window?
Yes, if you choose the same cut-out size and the wall is 25 to 75 mm thick. All EuroVan windows except the VanCurve fit flat caravan and motorhome walls.
Ready to fit? Pick your window by type, tint and cut-out size.
Shop campervan windows
