Note – if you’re going to do this outside, make sure it’s not going to rain anytime soon.
Some van’s come with roof rails pre-installed. If so then great. If not then you can either order one from the vehicle manufacturer (in my case that’s Mercedes). I decided to go with the slightly cheaper custom job using a generic T-track aluminium extrusion.
Depending on where you are based a custom aluminium extrusion can be more or less hard – in the UK there aren’t many options apart from the one I found linked in the list below.
List of materials:
- Hairdryer or heatgun
- Screwdriver/chisel and plastic hammer (to remove plastic hole covers)
- Marker pen
- Drill bits (for metal)
- Flute countersink drill bit
- Countersunk bolts, nuts and washers (M5)
- Mastic tape (40mm wide)
- 6mm rubber grommets (or Sikaflex sealant – for waterproofing over holes)
If you’re using the T-track linked above you’ll have to cut it to suit your needs. I only needed 2/3 of the length of my van roof covered so I cut the 5 metre long T-track in half to have two 2.5 metre long T-track rails.
Removing hole covers on the roof (such as on a Mercedes Sprinter)
I did this with a hairdryer but if you have a heat-gun then all the better. Blow the hot air over the plastic plug for a minute or two before using a flat screw driver or a flat chisel to slip under the seam of the plug. I used the twisting and turning motion to break apart the glue holding down the plug before going inside the van and knocking it out from the inside.
Drilling the roof rail
Place the T-track on the roof and position it exactly where you would like it to be. Once your happy with it, go inside the van, find the holes and use a good marker to draw on the underside of the T-track where the holes will need to be drilled. Obviously, you’ll need to the same thing on the other T-track.
Take the T-track and drill holes through the bottom of the rail using the pen marks you drew earlier (drill bit size I used was 5mm). After doing that, if you bought the same countersunk bolts I did, you’ll have to use a flute countersink drill bit on the top end of the holes (the one I used was too big, but if you’re using the same T-track I did, use a xxxxxmm).
Installing the roof rail
Before installing the rail on the roof, you’ll have to place mastic tape on the bottom of the rail to help waterproof it. After that you can pierce the mastic tape with a sharp screw of some sort in order to more easily push the bolts through.
To further help waterproof the installation it is good to try to put a rubber grommet around each hole on the roof of the van. I personally just put a blob of sikaflex sealant on there before placing the whole rail, including the bolts through the holes all in one go.
Give the rail a good push during the install to help the mastic tape and sealant stick to the van. Once this is done you have to install the washers and nuts on the inside while someone outside is on the other side keeping the bolts static using the relevant tool. Once you’ve put a washer and nut under each bolt, make it nice and tight to make sure everything is sealed.