How to Fit a C-Channel Awning Rail Under a VW T4/T5/T6 Elevating Roof

We have many calls from VW T4, T5 and T6 owners asking what sort of C-channel awning rail they should buy and in what position it should be fitted under the elevating roof of their van.  As there are so many different designs of elevating roofs fitted to VW campervans, many of which have also evolved and changed over the years, we can’t comment on fitting under specific roof types.  Whichever elevating roof you have fitted to your van; Reimo, HiLo or any other make, the principles are the same and we’ll run through the options below.

Hopefully, this 'How To' page will help you to establish which type of awning rail you need, where to position it and decide whether to attempt fitting yourself.

Fitting an awning rail under an elevating roof (aka pop-top in Vdub speak) is obviously easier at the conversion stage, but still fairly straight forward to fit retrospectively for most owners with basic DIY skills.  As the rail is hidden under the roof and only on show when the pop-top is open, and then probably with an awning in front it 95% of the time, most Vdubbers have a go. If you really don’t feel up to the job, contact your local conversion company or auto body shop who’ll usually be able to help.

Overview of Positioning and Type of Rail

Basically, there are only 3 positions under an elevating roof where an awning rail can be fitted, and depending on where the roof fabric, scissor hinge and gas strut finishes, sometimes just one or two. Deciding which position is right for you will depend on any limitations of your elevating roof design, your DIY skill level and whether you’re willing to disturb scissor hinge/gas strut connections.

The roof gully is the 50mm wide x 12mm deep channel at the edge of a VW T5/T6 van roof – where the side of your particular elevating roof finishes in relation to this channel will determine your options for fitting.

Only two C-channel profiles work under an elevating roof; standard profile C-Channel Awning Rail fitted flat in position 1 on the van roof next to the roof gully or fitted vertically in position 2 to the outer edge of the roof gully and C-Channel Awning Rail for Roof Bars fitted in position 3 at the base of the roof gully.

Position 1 – Standard Profile Awning Rail Fitted Flat next to the Roof Gully

Standard Profile Awning Rail Fitted Under a HiLo Elevating Roof

The side fabric, scissor hinge and gas strut of some elevating roofs finish inward of the roof gully (as with HiLo roofs) with the rubber edge seal closing into the roof gully. This type of elevating roof design usually retains a raised section of van roof in between the side of elevating roof and roof gully which is a good position for an awning rail and very straight forward to fit.

With most other wider elevating roof designs, the fabric extends further towards the edge of the roof and finishes at the inner edge of the roof gully with the scissor hinge and gas strut connections fitted in the base. Fitting a rail in the roof gully is a bit more involved than position 1 and sometimes requires the rail to be slightly modified.

Position 2 – Standard Profile Awning Rail Fitted Vertically at the edge of the Roof Gully

Standard Profile Awning Rail Fitted Vertically at the edge of the Roof GullyStandard Profile Awning Rail Fitted Vertically at the edge of the Roof Gully

One thing to consider with this position is whether any of the scissor hinge or gas strut bolts will snag on the C-channel of the awning rail as the elevating roof closes. Either measure the gap under the bolts and check the clearance with the rail dimensions or order a rail sample and tape it in position while gently closing the roof to determine this.  *Please note: the base of our standard awning rail is now marginally wider so it may extend a slightly higher in this position with a 7mm to 10mm gap between the underside of the C-profile and van roof - if in any doubt we recommend trying a sample section before ordering any of our rails.

Standard Profile Awning Rail Fitted Vertically at the Edge of the Roof Gully in 3 Sections

If 1 or 2 of the bolts are going to snag, you will need to either cut out 5cm section/s of C-profile out of the rail to accommodate the bolt and fit in one length or simply cut the rail and fit in 2 or 3 separate sections.  As Kador connection piping is flexible, it is relatively easy to redirect around any bolts and back into the C-profile of the rail.

Position 3 – Roof Bar Type Awning Rail Fitted in the Base of the Roof Gully

As above, hinge/strut bolts can sometimes snag in this position – check and follow the same guidance.

To determine whether this option is right for you, you will also need to consider how easy it will be and whether you’re willing to unbolt the scissor hinge and gas strut connections in the gully.  Campervan conversion companies often use Sikaflex adhesive or silicone as well as the bolts at these connection points which can make them a bit awkward to undo and both will obviously need resealing as the awning rail is fitted.

Fitting a rail in this position is quite a bit more involved and not for everyone. On the plus side, you will be sandwiching the awning rail under existing connections and you can usually use the 2 or 3 other fixing points in the gully which have M6 hex blanking bolts to secure the rail – which may mean no drilling or screws needed.

Alternatively, if you don’t want to disturb the hinge/strut connections, this profile rail can be cut into 3 x sections and bonded or screwed in between/ either side of hinge and strut.

What Length Awning Rail Should I Order?

The Kador connection (the round piping that slides into the C-channel) on most sun canopy and drive-away awnings is around 240cm and 260cm long respectively. Don’t be too concerned if you don’t have enough space to fit a 240cm or longer length of awning rail as you will use a drive-away kit to connect to a drive-away awning. The two components of a drive-away connection kit come in 3m lengths and can be cut down to match the length of your drive-away awning Kador connection. The 3 x 1m lengths of figure of 8 parts are rigid plastic strips which extend than the length of the awning rail and keep the fabric of your drive-away awning connection tunnel nice and taught.

The maximum length rail that will fit in the gully of a SWB T5/T6 is around 240cm, 280cm on a LWB.

Ideally the rail should run from as far as possible from the rear of the van to at least a few centimetres forward of the side door opening. This helps to pitch a drive-away awning as far towards the rear of a SWB van as possible to allow the sliding to open fully without putting too much pressure on/damaging the connection tunnel of the awning. This is more of a factor on MWB vehicles where the sliding door opens almost all the way back to the rear pillar of the van.

Also, when using a waterproof sun canopy in wet weather, this position of awning rail allows the side door to remain open with opening and door both under shelter.

What is the Best Method of Fitting an Awning Rail – Glue or Screw?

An awning rail can be fitted to a campervan roof using either chemical bonding like Sikaflex 221 or similar and/or a physical fixing like self-tapping screws or pop-rivets. Your choice of fixing method really depends on what you’re most comfortable using.

The awning rail coming off down a motorway isn’t an issue here as it’s under the pop-top. However, consider the tension of a sun canopy or drive-away awning fabric pulling against a rail in windy conditions… nobody wants a detached aluminium rail flapping against the side of the van in the middle of the night.

Most VW Bus owners, dread the thought of taking a drill to the roof of their van for fear turning their home on wheels into a sieve!  As long-term Vdub owners ourselves, we can of course understand these concerns. However, if you do decide to use adhesive to avoid the dreaded drill, make sure you mask surrounding areas, have plenty of rags on hand in case things get messy and allow adhesive to cure properly for at least 24 to 48hrs.

A physical fixing is usually 100% secure and a few strategically placed spots of silicone sealant will ensure it will remain completely watertight. When we fit an awning rail to one of the Funky Leisure wagens (in a position where we can’t use the existing roof bar fixing points) our preferred method is to use self-tapping screws with clear silicone sealant.

Basic Guidance for Fitting a C-Channel Awning Rail

  1. If necessary, cut the rail to length.
  2. If you are fitting the rail in one full length, carefully put some gentle bends downwards toward each end of the rail to roughly follow the curvature of the roof.  If your fitting the rail vertically, this will need a little more pressure and will be easier with a second person or workbench vice – don’t overdo it as this doesn’t have to be exact, it will just help the rail seat better on the roof while you fix it.
  3. Make sure the roof area is clean and tape the rail in position with the C-profile facing out from the van roof.
  4. If you have decided to use adhesive, mask the area surrounding the rail and bond as per manufacturer’s instructions - allow the adhesive to cure properly. If you have decided to use self-tapping screws - follow the instructions below.
  5. Using a 2.5mm drill bit drill 4 x pilot holes through the rail and roof surface. If you prefer to do this in two phases, you can pre-drill the rail, lay it on the roof, apply masking tape, mark and then drill the hole positions in the roof.
  6. Remove the rail from the roof, enlarge the holes in the rail with a 3.5mm/4mm drill bit and debur the underside.
  7. Dust any drilling debris from the roof and lay the rail back in position with 3.5mm x 13mm (No.6 ½”) self-tappers, silicone and kitchen roll on hand.
  8. Starting at one end, lift the rail slightly and squeeze a small blob of silicone on top of the first hole in the roof and the hole on top of the rail, put the screw through the hole in the rail and locate into the roof hole. Screw the self-tapper in a couple of turns and move on to the next hole - repeat.
  9. When all screws have been located, tighten them and wipe away any excess silicone.

Are There Any Alternatives to Fitting an Awning Rail Under an Elevating Roof?

If, for whatever reason you decide not to fit an awning rail under your elevating roof, the only other alternative is to have a Multi-Rail fitted just above the top of the door line. The Reimo Multi-Rail is the best quality multi-rail and the market leading design.

If you’re not quite ready to fit an awning or this article has put you off completely (sorry – just telling it like it is!), the Throw-Over Straps/Guyline connections that are supplied with drive-away awnings actually work quite well with elevating roofs. The strapping points on the awning connection tunnel are wide enough apart for the webbing straps to go around the front and rear of the pop-top and peg down on the opposite side of the van.

The straps are adjustable, so can be slightly tensioned against the side of the elevating roof which keeps them in place while you pitch the awning and restricts any movement to the front or rear.

We hope this information has been useful in helping you to select and fit the right awning rail for your van.

The Funky Leisure Team