5. I'm not defensive, I'm just putting my walls up.

It's insulation day!

There have been lots of jobs going on at once, on the inside and out, so the first thing that needed to be done was a big clean up. All of the tools were put away, all of Lorca's walls wiped down, and everything vacuumed. The trash was disposed of, and after doing all of that (which took over an hour) I found a great deal of satisfaction in seeing the floor again clearly.

All of the small nooks and crannies were stuffed with Earthwool (R4)...

... and the larger spaces had Foilboard (reflective closed cell foam with a silver foil on the outside surface, and a green coloured one on the inside) cut to size and fit to the spaces. These were then held in place with aluminium tape.

Like so.

You can also see in that picture that pieces of the board were cut and taped between the metal wall and the Foilboard as spacers. This is because in order to be properly effective the reflective side needs an air gap, and these little spacer blocks ensured that gap is maintained.

A closer look.

The manufacturer recommends a 4cm gap, but this is a van build, and we don't have the luxury of any of that. The gap is close, but it's not a standard 4 cm's.

I bought a new tool for the job- a hot foam cutter. I was dubious about its effectiveness, but pleasantly surprised, as it was actually way too powerful, and set fire to the foam. But it had a variable heat setting, so once that was dialled back a bit, cutting became very quick and easy.

In action.

Any gaps were trimmed to be as small as possible, and covered in aluminium tape. Vehicles are basically impossible to insulate 100% effectively, which is another reason why airflow is so important. Heat will seep through the cracks and thermal bridges (more on that later), but if you have a good system for air circulation (cool air in, hot air vented out a roof fan), then the effect of the leakage can be minimised. Eventually I will also install an awning whose job is to keep the sun off my exterior walls and allow air to circulate in that shade, drastically reducing heat transfer further.

Cold air falls downward, and is a whole other concept. But at a later stage I will be installing a powerful diesel heater system, which will be more than enough to deal with Melbourne winter weather.

A gap before taping..

This last pic shows how tight I kept the gaps, to minimise heat transfer from the outside to the inside. Once all the Foilboard was installed and taped into place, the drivers side wall looked like this:

The gaps in the Foilboard are where the bumpout on that side will be, so there's no point insulating that metal, as it will be cut out and replaced with a rectangular fibreglass bubble eventually.

When I bought Lorca she came with grey coloured plywood wall panels from Renault. Before putting them back up, I stuck adhesive soft foam strips around the edges of the panel areas, to stop the panels from rubbing against the paint. This may not be necessary, as the entirety of the van body is galvanised, but I figured it couldn't hurt (and is a great way to finally use up a big roll of adhesive foam I've been sitting on for years!)

I said I'd talk about thermal bridging too. Vehicles are full of these- basically parts where the hot sun on the outside of a surface can make its way inside, because the heat travels through a metal part like the steel ribs. Even though they have been stuffed with Earthwool, once those steel tubes get hot on the outside, that heat will travel inside and radiate into the air. Because Lorca has a lot of steel in her cargo area to keep the walls together, that's a lot of opportunities for heat to 'bridge' inside. So by adding these foam strips which don't conduct heat between my ribs and the plywood wall panels, it effectively halts that unwanted transfer of heat.

The foam strips look like this.

Then the wall panels from the manufacturer went back up...

These grey panels are ugly, I know... I have attached them firmly to the steel using machine screws, and in a couple of places will be making and installing extra supports made of wood. Then tongue and groove boards will be adhered to these panels for the final look. Then the panels will be removed again, and those boards will be screwed in from the back for extra strength. Then the panels will be reattached, and the walls will look nice.

I'm thinking of using Merbau for the boards. Merbau looks like this:

Of course the roof will need to be insulated too, and it will be. But before that is done I have to make new roof beams out of wood to hang the ceiling on, so that will be another post.

It's a bittersweet moment. I have a mental list of milestones he wants to achieve with this build, and getting the wall panels back up was one of them. But it's bittersweet because I've worked for days on the Earthwool and Foilboard insulation, and all that work is covered up, so it just looks like a cleaner version of the day I bought the van.

But one milestone enables another, so this being done means attention can be paid to a new area. I hope you will join me for that...

See you next time!