2017-08-06: Bench bed and cladding test

We’ve been busy on various jobs since I last wrote, mostly trying to get some basic components built in prototype form for we can take the van on a short trip and test some things out.

Almost every design/build problem in the van is a chicken and egg problem. And we tie ourselves in knots trying to decide which part to commit to, so that we can move on. The interaction of furniture, cladding, and electrical supply is one such problem.

Since we had to start somewhere, we took the passenger side of the van as a low risk first step.

Bench bed

I started by building a simple bed frame. It’s mostly self supporting, with the legs nearest the wall bolted to the van body using rivnuts.

Bench/bed frame

I set the frontmost legs back from he edge of the bench so that, when seated, you can swing your legs back. The front and sides will be panelled with ply, as will the top. For now, we have a piece of MDF on top to use as a test. The front edge of the bench has a 2cm lip which will form the middle (longitudinal) support for the bed. The other half of the bed will be removable, with one edgeand resting on this lip, and the far side resting on a lip on cabinets (still to be built) on the other side of the van.

Structure of the bench largely complete


Once the bench was complete, we spent many hours figuring out how the cladding could work. The van walls are curved, and flexible plywood could conform to the curve, but there are very few places where it could be pinned back to the walls, risking it flapping around, unsupported, or ‘drumming’ when on the move. So we decided to build a flat frame for the middle section of the wall, onto which one large sheet of flat ply can be fastened.

To clad that section, we re-used some of the 5mm plywood that was in the van when we bought it , cutting out holes for the task lights and USB sockets. It feels pretty solid, so we’ll see how it works on our trip in a couple of weeks.

One wall section insulated, with electrical supply, and framing up ready for cladding

2017-07-09: Fitting roof light and fan

We fitted the fan and the roof light this weekend. Each job took a whole afternoon.

I started with with the Maxxfan. I didn’t take many photos because the whole job was a bit stressy and I wasn’t sure it was going to work. I needed to concentrate.

The Maxxfan is great – we were pleased with it straight out of the box. The plastic is not flimsy, installation is well thought out and it looks good. It is designed so that you can fix a retaining ‘flange’ to the roof and then the machine itself screws onto the flange later. This means you can easily remove the machine for repair without having to phaff about with the bit that holds it onto the roof. Likewise, the decorative bit inside that hides wires etc gets screwed in place independently.

This is a bonus for us because we don’t yet know what we are going to clad the van with, and how thick the roof will be. So we can still drive about with the fan fixed in and worry about trim later.

Caravan bits are designed for flat roofs. The sprinter doesn’t have a flat roof in any direction – it has bobbly bits which can’t be avoided.

I started by trying to draw the 40cm square  for both the roof light and the fan on the ceiling of the van where we wanted the holes to be.

This was very difficult, (rulers too long/ short/ bendy, neck and arms hurting, right angles never matched up).

marking the roof light square inside the van

I got fed up in the end and using a punch, made some discrete mini dents (one at each corner) then got up on the roof and using the dents as a guide measured the 40cm square again (much easier on the roof).

Here’s the square for the fan:

The square marked out for the fan (close to the back of the van)


And here is square for the roof light

The 40cm square for the roof light, near the front of the van

Then I cut out some squares of some plastic stuff we had hanging about at home that we found on a skip. (Andrew know what it’s actually called – Andrew: it’s called expanded PVC). it’s bendy, about 6mm thick and can be carved easily with a Stanley knife. The squares matched the flange for the roof light  (variable widths) and the fan  (same width all the way around) and also had a 40cm square hole cut in the middle.

The plastic insert for the roof light

Next I carved bits out of the plastic insert to correspond to the bumps on the roof. Each cut is at about a 45 degree angle or more to accommodate the roof shape at best as possible.

Then I sanded the plastic and cleaned it with degreaser.

The following photos and account are mainly the roof light, but I’ve slipped in a couple of photos from the fan where I didn’t have the equivalent roof light photo.

We were pretty disappointed with the roof light when it arrived. It was advertised as white but is in fact more magnolia coloured. It feels flimsy, and the installation needs you to have determined the thickness of your roof.

The roof light. (No forced ventilation so it doesn’t whistle when we drive)

I sellotaped a bin liner inside the van to catch the worst of the metal filings, and a bit of cardboard on the roof to try and stop them getting under the solar panels.

The bin liner sellotaped inside the van to catch metal filings (fan)

Then the noisy bit!

Up on the roof again, I drilled a hole in each corner  (10mm bit) for the jigsaw bit to start in. Then I cut the four lines.

To minimise vibration I put duck tape across each cut I had made when I finished that side of the square. It also stopped the cut out falling into the van.

I didn’t bother with masking tape on the plate of the jigsaw because everything is going to be covered with sealant. We have a cheap  £40 jigsaw from Machine Mart and it did the job fine. Going over the bumps was noisy, wobbly and a bit tricky, but I found if I kept the front of the base plate pressed down where possible while keeping it level, it didn’t matter too much that the back end was in the air and the blade coped ok.

Hole cut for the roof light

The bit of cardboard didn’t work – the filings got everywhere. So after filing down the edges I hoovered the whole roof and everywhere else and removed the bin liner carefully.

I sanded the edges and a little way around the opening, cleaned with degreaser,  painted Hammerite primer on the bare metal edges and had a cup of tea.

Then I stuck butyl tape (see in the picture above) around the opening to seal the plastic insert to the roof.

Butyl tape stuck around the hole for the roof light

The tape was 20mm wide so in some places I used two strips. You can cut it with a Stanley knife. It’s like chewing gum.

Then I put the plastic insert on the top of the tape:

My plastic insert on top of the butyl tape.

I used Sikaflex Caravan Sealant 512 (also pictured in earlier photo) to seal all the way round and fill any gaps between the insert and the bumps on the roof.

This sealant sets (stops being sticky) but stays rubbery. I think the butyl tape doesn’t set (the bag it came in was not airtight at all). Ordinary bathroom silicone sealant which I intended to use originally dissolves the butyl tape and turns it into a slimy mess (lucky I tested it first).

Now the insert was in place I wanted to get everything tightened up together before the sealant set.

In the case of the fan, I put a continuous square of butyl tape on top of the plastic insert and the provided roof insert is then screwed (using about 20 screws) through the metal of the van roof. We also cut four bars of wood and clamped them inside the van so that the screws went into wood after they had gone through the roof (the sandwich of materials went like this from top to bottom: maxxfan plastic roof insert, butyl tape, my homemade plastic insert, butyl tape, roof metal, wood) Then I sealed all around the edges and over the screw heads in a big smeary mess.

The fan in place and fixed to the plastic flange insert that has been screwed to the roof  – you can just see the screws.

The bits of wood that we used inside the van were a last minute decision when we realised how the screws just poked randomly through the roof.  They aren’t totally necessary. In retrospect it would be better to make something neater and smaller in advance (like we did for the roof light).

In this picture the fan has already been lowered into the plastic fixing flange in the roof hole.

The roof light was slightly different. Since repairing or replacing the roof light involves removing the entire thing- the seal needs to be less permanent.

I applied a thick bead of Sika Lastomer 710 as per instructions to the underside of the roof light. and eased it into the hole. This stuff stays flexible and sticky, like the butyl tape.

This picture shows the underside:

Underside of roof light

It is supposed to have a clearance of 2-3mm all the way round. (my hole was a titchy bit tight but its almost impossible to re-jigsaw a cut and filing more than 1mm off a cut edge isn’t feasible either, so i’ll just have to hope its OK).

I used about half the tube of Sikaflex and it bulged out nicely from under the plastic so I know I got a good seal, but it was a bit messy clearing the excess away.

Roof light sealed into place

Off the roof and into the van now.

Here is the bit that fits inside the van:

Roof light plastic insert fits inside the van.

Andrew had earlier made a 40cm square out of 12mm plywood, 50mm deep and held together with small metal brackets at the corners: you can see it in the video at the end but I forgot to photograph it.

This filled the gap inside the van between the bit of the roof light that sticks through the hole you’ve cut and the bit of plastic inside the van (way more complicated and fiddly than the maxxfan). You are supposed to measure the gap between the inside of the roof and the cladding of your van to calculate how much to chop off the plastic bit inside the van.

We haven’t insulated or cladded the van yet so we had no idea about this. The maximum depth the plastic can extend to without leaving a gap is 60mm anyway and since our celotex insulation is 50mm, Andrew thought the wooden frame should be 50mm deep. Turns out that this was a perfect guess.

The plastic bit that fits inside the van and is supposed to slot inside the plastic square poking down through the hole. The screws marry up and their plastic surrounds butt up against each other. This is what braces the inside part and outside part and holds the roof light in place.

Yep- we thought it was all rather flimsy too. So the wooden frame is to prevent too much compression.

Roof light stuck onto roof and inner plastic flange screwed into place from inside the van to pull it down onto the roof and tighten the seal. Wooden frame sandwiched between the two parts.

Later you clip the rather hideous peachy plastic trim to the plastic bit I’ve just screwed into place. Won’t be doing that till we’ve cladded the van inside.

Decorative trim that goes inside. Nasty mottled beige blackout blind and a useful fly screen.

Next I went back onto the roof and attempted to clear up the bulgy bits of sealant. Not very successfully – it looked rather a mess.

This bit wasn’t too bad. You can just see the plastic insert I made.
This was the worst bit – where I tried to clear excess Sika Lastomer, I disturbed the not quite set Sikaflex sealant I had applied around my plastic insert

Here are the tools I needed for the job.

Ladder, Towel, Jigsaw with metal blade, Drill and 10mm drill bit for metal,  extension cable, hoover, ear muffs, googles, Hammerite paint and small brush, metal file, Sharpie, ruler, set square, tape measure, pencil, punch and hammer, duck tape, masking tape, large bin liner, paper towel, degreaser (strong detergent), sandpaper, butyl tape (20mm X  9 metres was plenty) SikaLastomer 710, Sika Caraven sealant 512, caulking gun, screw drivers, a few bits of wood and angle brackets and a couple of large clamps, a sheet of 6mm plastic, Stanley knife.

Tools for cutting the hole in the roof

Here is the Plastic insert I made, Sikaflex caravan sealant 512, Sika Lastomer 710,

The plastic insert I made, Sikaflex, SikaLastomer and butyl tape.

Here’s the video:





2017-07-02: Starting the electrical install

This weekend, we started running cables and mounting components so we can get the electrical systems hooked up. We already have the solar panels on the roof, and the battery fitted under the passenger seat. We also have a fair amount of conduit routed through the side panels of the van so we can run cable from front to back (e.g. from the fusebox to the ceiling lights or rearmost USB sockets).

Green lights are always a good sign. We are now successfully charging our battery from our solar panels. Very exciting.

Nothing at this stage is fixed, but we need to commit to some decisions so we can continue the build. So it’s a delicate balancing act of deciding where things should go, while leaving options for us to change our minds. In practical terms, that means:

  • Making prototype mounting boards and boxes for components roughly out of MDF to test out placement and design before rebuilding them properly in nicer plywood.
  • Making some educated guesses about where we want wires to emerge, and cutting cables to length.
  • Wherever possible running wires – cut to a generous length – through conduit so we have some flexibility in exactly how we place the end components (lights, sockets, appliances, etc.).

Our electrical system starts in the area immediately behind the cab. It’s something of a no-mans land that in many conversions would just be wasted space. We’re hoping this will be a space-efficient placement. The main elements are:

  • Leisure battery in the passenger bench seat base (with space for a second battery in the other half of this seat base if we need to expand)
  • Solar controller on a board mounted to back of passenger seat base (with space for some other components we might add later, such as a battery-to-battery changer, inverter, or mains power charger)
  • 12V fusebox and distribution mounted to back of driver’s seat base.

By separating the ‘power in’  (solar, alternator, shore/hookup power) and ‘power out’ (12V circuits) into 2 areas, we have more space to mount components without intruding into the main living space of the van.

Meanwhile, the insulation installation continues, as we desperately try to clear our house of bulky building materials.

We’re getting through cans of expanding foam at an alarming rate.

2017-06-25: Solar panels


Another big job done this weekend, and one we faced with some trepidation – installing the solar panels. While they’re not yet wired up, they are now mounted on the roof. It’s a very tight fit up there, as we want to fit 2 large panels (1m x 1.3m) as well as a roof light and fan.

Cleaning and polishing the roof. Our last chance before we cover it with solar panels.

We had measured the available space, and checked for obstructions both inside and outside, but until you start the job, there are no guaranteees. Sure enough, we soon discovered our first brackets supplied with the panels didn’t  quite fit between the raised ledges that run down the edge of the roof. So we had to mount the brackets on the inside of the aluminium frame of each panel. Mounting to the panel was easy, but when it came to mounting them to the roof, the brackets were underneath the panels.
This was the easy bit, before we had to deal with misaligned holes and bolts in hard-to-reach places

Aluminium angle brackets mounted underneath the panels. The only way to fit them on our roof
Fabricating some spreader plates to go on the inside of the roof skin, to spread the load in case of an upward force in the panels
Spreader plates. The clear goo is the CT1 adhesive

So we had to lay the panels where we intended to place them, mark all the holes with a pencil, move the panels aside, drill holes and then hope they all lined up. 

As well as M6 bolts (2 per bracket, 4 brackets per panel) fastened with locknuts, we also glued each bracket down with CT1 adhesive and fabricated some aluminium spreader plates to spread the load on the inside of the roof. 

We also made some progress buying materials we need to fit the rooflight and fan, installing more insulation, and treating more rust we found on the roof.

2017-06-21: Shopping

This shouldn’t warrant an entry in the build diary, but we’ve spent so long researching equipment to fit out the van that I need to get it off my chest.

Spending money like there’s no tomorrow

We’ve been focusing on the electrical systems, so we can get all these installed before we do any more insulation, or start on cladding or furniture.

So in our front room, we currently have:

  • 2 Solar panels
  • Solar charge controller and monitor
  • Leisure battery (now fitted)
  • Maxxair Maxxfan
  • Dometic Mini rooflight

… as well as rolls of conduit, insulation panels and the original plywood cladding we removed from the van.

I’ve just sent off an order to 12 Volt Planet, who, so far, have been super-helpful, and have a really good website for speccing out electrical components. So in the next few days we can expect poly bags full of fuses, crimp terminals, stranded wire, lugs, switches, USB sockets, LED lights and more.

It’s been an interesting process figuring all this out. But literally days of work just to figure out a shopping list. Working out all those details (What will be the voltage drop if we want to run lights all the way to the back of the van? What kind of terminals can we use on each component? How many USB sockets do we need? etc.) is a complex task, and every answer opens up more questions.

So let’s hope I bought the right stuff!



2017-06-17: Fitting the leisure battery

The new battery safe and sound in it’s box. I hope.

We’ve put a hold on installing insulation because we’re concerned about how complex it’s going to be to run wires for the electrical systems. So we’re trying to get some of that in place so we know where we stand.

First step, installing the battery. It needs to be somewhere safe, accessible, but not ‘everyday-accessible’, and secure when in transit, or if, in the event of accident, the van was to roll over.

We’re using the base of the dual passenger seat. Ideally it would go in the middle base, but there is an access panel there to some other wiring, so we’re putting it in the outer base (left hand side on our UK van). I thought this would be a simple job, but it ended up taking the best part of a weekend.

I made a plywood floor, set on battens that even up the slope of the seat base. The floor has a set of battens into which the battery sits – these stop it sliding around. It’s also tied don to the floor with webbing strips, and the floor is then bolted to the front and back of the seat base so that the whole assembly should remain in place should the van roll over.

As with any job that involves fabricating a piece to fit into a pre-existing, irregular hole, what could be a simple task soon becomes endlessly frustrating. And of course it’s not made any easier by the 30kg weight of the battery, which is a tricky son-of-a-bitch to ease into place.

We had originally specced these batteries with the intention that we could fit two into a seat base if want to expand our capacity later, but that’s not going to happen now – we’d need much more room to manoeuvre. So we’ll have to figure that one out as and when…

2017-06-11: Research, planning and insulation

Something of a slow grind since we got back from our first trip. We’ve both been very busy with work, so not much time to spend on the van.

Amy has been insulating the rear and side doors. Since these cavities hold loose wires that connect to the central locking and door catches, we don’t want to install insulation that can’t be removed if we need to fix any problems. So we’re using left over closed cell foam sheets (about an inch thick) which can be friction fitted without using any glue or expanding foam.

I’ve been drawing more layouts in Sketchup, trying to iron out all the little niggles, and figure out what we can pin down now so we can continue the build. It’s a constant struggle between getting stuff done, so we can test whether it does work, and planning things out, so we know that it will work.


Current draft layout. Yes, I know it doesn’t conform to the laws of physics. It will.

At this stage, while we’re trying to maintain maximum flexibility, that means a lot of shifting sand.

So we’re trying to make some decisions on the electrical system:

  • What battery technology to use
  • How much capacity we need
  • How much solar we need
  • What arrangement of panels will work best on the roof (in combination with other components like a fan or a rooflight)
  • How to run wiring through the van
  • How to charge the battery off the alternator, and what system will work for our van (voltage sensitive relay, or battery-to-battery charger)

2017-06-01: Minimum viable build

It’s half term week and we’re supposed to be on holiday. We haven’t made it out yet, in part because we wanted to get some basic jobs done on the van before taking it out on its maiden voyage: a floor, a window, and a few bits of basic furniture.

With the window in yesterday, all that remained was to bodge together the furniture we needed, and that would give us a sense of what living in the van might be like.

We don’t have a place for Loki to sit up front in the cab when we’re driving, so I made a raised platform behind the seats so he can sit more safely in the back , but still see out of the windscreen. I also wanted something in the van to give an impression of a kitchen, so I reassembled an old flat pack storage unit that’s about the right height, and bolted it onto the side of the van by the door.

With a few rugs, bungee straps and camping equipment, we were ready to hit the road!

2017-05-31: Side window install

After a few evenings of what seems like little progress, it was good today to tackle one of the hero jobs, installing a window.

I’ve watched more videos on window installs than I can remember, but the most useful is probably this one:

I won’t recap what you can see better on YouTube, but it’s worth sharing a few things we learned:

  • Find a good supplier of windows who can provide good after-sales support. We used Van Demon, here in the UK,  and I can’t recommend them. They refused to give any advice on installation, and they were uncooperative about swapping items they’d sent that weren’t right for the job.
  • Beware swarf when cutting the hole. It gets everywhere. We taped up the window on the inside, and masked off the area around the window on the outside. And the first job we did after cutting the hole was to vacuum up the swarf and metal dust.
  • Have a spare tube of adhesive within reach. We bought the fitting kit advised for this window, but added an extra tube to be in the safe side, and I’m glad we did. We didn’t use it, but we were right at the end of the first tube by the time we’d run a bead round the glass.
  • Use a suction grip to lift the window. We rushed down to the tool shop half way through the job because it was just too tricky lifting the window with only our hands, especially after we’d glued it up.
  • Glue the window, not the van. Most of the YouTube videos seem to do it the other way round, but I’d say this way is easier.
Marking out the cut line


Cutting the window opening. And really pissing off the neighbours
Painting the cut edges
One window installed

2017-05-30: Admin, insulation, conduit

Today has not been the most fulfilling of days. I spent half the morning on the phone trying to sort out spare keys and the correct trim for the new window we bought. Amy was swapping materials at Screwfix. Then we tried to figure out where to route the conduit to allow for wiring up the solar panels and any 12V electrics in the van — which is tricky given that we haven’t decided where any of that is going to go. Then we fixed more rust, cut more Celotex insulation boards, sprayed more expanding foam … the same as we’ve been doing for days now it seems. We’re getting through cans of foam like there’s no tomorrow, and I can also tell we’re going to have to swap some of the insulation boards I bought for thinner ones, as the cavities at the back of the van are much shallower than those at the front. 

Treated and repainted door retainer

Fixed door retainer

Treating the rust where the sliding door stopper hits the van body

Marking the routes for the conduit so we can remember where it goes
I did manage to finish one small job, which was to improvise a raised platform for the dog to sit on behind the cab seats so he can go in the back comfortably while we’re driving. And Amy had success fixing one of the rear door magnetic retainers on the side of the van, which was poorly seated and letting in water. We want to go away in the van for a few days at the end of this week, so we’re just trying to get it fixed up enough to do that.