Our 10 Worst Van Build Mistakes

About to embark on your first van build? Congratulations! We know how exciting it is and how eager you can be to jump right in. Get these first few planning stages right and we’re sure your van conversion will go perfectly. 

We did lots of research for our van and yet we still made a few mistakes during our build that we’d definitely try and do differently on another conversion. We recently wrote about the changes we would make to our van if we were to do it again, and it’s one of our most popular articles. So, we decided it was time to own up to all the mistakes we made during our build as well! We hope you’ll find our experience helpful, and hopefully you can avoid some of the pitfalls we fell in to!

Our 10 worst van build mistakes and how to avoid them

1. Layout – Finalise your layout as early as possible

We put quite a bit of thought into our van layout, however we didn’t completely finalise it until our Happijac bed lift was delivered. We ran electrics, insulated and installed ventilation before we decided on our final layout. I don’t recommend this!

Luckily this has only caused us one major issue and that’s with our ventilation. We have two fans, a Maxxair fan in our kitchen and a Fantastic Fan at the back of the van. Sadly, the one at the back is usually covered by our bed!

We weren’t 100% sure we would manage to get our bed lift to the UK and it took quite a few months of planning to get it ordered, shipped and delivered. As we were keen to get on with our build we jumped right in and did everything we could whilst waiting for it to arrive. Once we got it installed we realised we were now blocking our rear fan when the bed was up (yeah, that should have been obvious!).

It’s not a major disaster as we can still vent with our kitchen fan to get rid of moisture. The main time it’s an issue however is in hot weather when we need two fans for air circulation. During the day we open all the doors, and at night we use the two fans together to keep us cool, which works brilliantly. 

It’s not perfect, and is certainly one to think about if you’re also using a bed lift in your build. On the other hand, I’m not sure where else we could position a second fan to avoid the bed space, so in reality we might not have done it differently anyway. Essentially, we recommend finalising the major parts of your layout before cutting any holes in your van!

2. Side Strip – Make sure you seal it!

Mercedes Sprinter vans have a few areas where it’s possible for water to get in to your van. The main culprit is behind the plastic side strips. These plastic strips push in to clips all the way along the van. Water can easily pour behind the strips and in to your van through these holes. 

Before you start insulating you need to remove the side strips and then seal the holes with Sikaflex before re-attaching the plastic strip. This will stop water getting in and soaking your insulation. Unfortunately, this is one thing we didn’t realise before starting our build and we didn’t do this.

It could have been a major van build mistake but we were actually really lucky. When we did eventually remove our side strips they were in pretty good condition and the clips were quite tight, so it didn’t look as though much water could have got through to our insulation… fingers crossed. 

3. Windows – Make sure they’re 100% secure

Our van came with two side windows already installed but we also wanted to add two rear windows for extra light in the back. We watched lots of videos on YouTube on how to do this but in the end we decided to pay someone else to install them as we were a little nervous about it.

This was a huge mistake! Well, I guess I should quantify that a little. The ‘campervan specialists’ we chose to do it weren’t as skilled as we originally thought! The holes were cut fairly neatly but the edges were left exposed without rust protection or trim. They used so much adhesive that we then couldn’t add trim ourselves as the adhesive was leaking around the edges.

The worst part though was that eventually both windows nearly dropped off! Not only could that have been incredibly annoying to have no windows in the middle of nowhere but worse it could have caused an accident if they’d fallen off on the road.

Luckily, when we realised they were loose we took them straight to a windscreen garage. They confirmed they’d been fitted incredibly badly and the adhesive hadn’t bonded to the van correctly. They were re-fitted and have been nice and secure since. Moral of the story? Either trust your own abilities or do a lot more research on people you pay to work on your van!

4. Van carpet – Finish a job before moving on to another!

There’s a few areas of our van we covered in carpet as they were hard to cover with wood. This includes around the side door and around the rear door frames. 

Our mistake here was not completing this part of the van build before moving on to something else! We did the carpet early on but there was a few bits we didn’t get finished and instead Will pushed on with cladding the ceiling (he wasn’t a fan of carpeting!). It’s much harder to do a neat job with other bits of wood in the way. We recommend applying van carpet after insulating and then the edges can be easily hidden by your walls or ceiling materials.

5. Weight – Monitor your van weight throughout your build

If your van has to stay under 3.5t it’s vital to think about the weight you’re adding throughout your build. It’s incredible how quickly the weight adds up, and it’s easy to be over once you’re all loaded up and ready for adventures.

Firsts things first, make sure you know the payload for your vehicle. The payload is the amount of weight your van can legally carry, add this to the weight of the vehicle itself (curb weight) and you’ll reach 3.5t.

Our biggest mistake weight-wise was not thinking about the weight we were adding to our van early enough on in our build. We only consciously started monitoring our weight once we got to the stage of constructing our interior space. By this point we’d already added windows, solar, electrics, insulation, ventilation, flooring and walls, all of which added a surprising amount of weight.

At this point we were around 2.8t leaving us 700kg for the interior fixtures and everything we needed to carry. Take off the weight of Will, Piglet and I (around 180kg), 100kg of water and 50kg of diesel (if tank is full), and we’re left with around 370kg to play with. 

Clothes, sports equipments, pots/pans, computers and food could then come close to another 100kg. This leaves just 270kg for all the interior of your build (kitchen, bathroom, bed, mattress, cupboards, benches, fridge etc). It’s definitely possible to still come in underweight but weighing your van regularly throughout the build process will help to avoid any nasty shocks at the end!

6. Flooring – Don’t go overboard!

This van build mistake is partly related to the above. Our floor is way too heavy! We laid a sheet of rubber on top of the metal floor, below our insulation, for sound deadening. We then have a wooden frame with insulation in-between and a 12mm plywood floor over the top. 

In hindsight we probably didn’t need the large sheet of rubber, especially given the floor we chose. We opted for heavy duty vinyl flooring on top of our plywood base as it’s incredibly hardwearing and we can walk on it in ski boots etc without damaging it. It’s definitely not the lightest though.

By the time weight started being a concern it was far too late to lighten our floor. We really didn’t want to rip out all our hard work thus far and so we carried on. If we were to do another build we’d definitely leave out the layer of rubber and opt for a slightly lighter flooring.

7. Water filler – It’s best on the outside of your van

Throughout our build we were keen to keep our van looking as stealth as possible. We were therefore very careful with what we have on the outside of the van and wanted as little as possible on display that would point to us being a campervan.

Instead of mounting our water tank filler on the outside of our van we decided to put it just inside the back door. This meant we could have one less hole on the outside of our van. We got it installed, plumbed in and tested, and were pretty happy with our decision.

That is until we headed off on our first trip and quickly realised what a stupid idea it was! Firstly, we were travelling in winter so every time we filled up we had to leave the back door open and therefore lost all our valuable heat from the back of the van. Secondly, if the water pressure was high water spilled out everywhere, straight in to the back of the van and soaked everything!

As soon as we were back from our first few months away we drilled a hole in the outside of the van and repositioned the filler. There are ways to make an internal water filler work but we decided repositioning it to the outside was the easiest option.

8. Doors – Always use primer when painting!

We decided against putting carpet on the inside of our rear and side doors, and instead decided to paint them. For us, having a different colour on them that coordinates with the interior makes them feel less like van doors and more like feature walls.

The big mistake we made here was not using primer. For some reason it didn’t occur to us to use metal primer as a base coat and instead we painted straight on top of the existing van paint. It was also January when we painted the doors, so the paint didn’t stand a great chance of drying properly in the cold temperatures. 

Needless to say the paint has scratched off in quite a few areas, especially where Piglet jumps up to look out the window! We’ve not re-done them as yet but at some point we’ll need to remove the existing paint, properly prime the doors and re-paint them to get a more durable finish.