Month: April 2017

Now that its insulated we can start building the interior! Its been a lot of work to get here, but there is so much more to go.

For the interior walls we are using a 1/4″ plywood, its prefinished birch. Reasonably cheap, just cut and install, not finishing needed. Its not the lightest, but works well. To install I used more construction adhesive (i think there are 9 quart tubes behind the walls and ceiling!) and micro pin nails. I’m happily surprised the nails hold really well.

I started with the easy square one…. Good practice anyway! I will come back and cut the windows from the outside with a router, this way the inside and outside holes match perfectly.

All these were cut with my old skill saw and a jog saw. Nothing fancy. I did my best to break the panels on windows, that way there were no seams running right net to them.

With the sides done we can install the windows. Ran into some issues here. I should have used a wood strip around the windows, not just the foam, this would have kept the correct wall thickness. I ended up having to shim the interior plywood out to make the walls the required 2″ for the windows to clamp too.

But with the windows in we are starting to get somewhere!

Windows were a big step. Tons more light and feels way more open. Ceiling goes in next.
I made a quick time lapse of the weekends work. There are some previews of what’s to com in the next post as well.

 

The walls are bare aluminum, there is a rib every 12″ that is one inch deep. We need a couple things here, 1″ is not enough insulation, we camp in sub freezing a lot and more is better. Also we need something to attach the inner skin of the wall to.  Also a vapor barrier is needed to keep the wall cavities dry and to keep the mold out.

So to do this, I cut strips of 3/4″ plywood down to screw and glue to each of the aluminum ribs.

This will give us 1 3/4″ of insulation, we are using polyiso spray foam, its R6.6 per inch, that will give us about R11.5 in the walls. The spray foam is also a very good vapor barrier, so we get a bonus there too.

The strips were glued on with construction adhesive and self tapping screws every 12″. They are quite solid. 1/4″ plywood is going to be used for the interior skin.

The ceiling (which apparently I didn’t take any pics of, will get 4″ of foam. I used 1/2″ plywood and 2″ foam board strips to furr it down. The ribs on the ceiling are much larger.

Everything you don’t want covered with foam gets covered, all the wires get taped down, and attached wherever possible. If not the foam can get behind them and push them off the wall. it goes on as nearly a liquid and expands as it cures.

I looked at doing a DIY spray foam kit, I have used them in the past, but this is large enough I would have needed two kits, its messy and just an all around pain. I decided to hire an insulation contractor to spray it. Money well spent IMO. If you do use the DIY kits, find and old cooler that the tanks fit in, and fill ti with very hot water, they work best when the tanks are above 70 ish degrees.

Getting ready for insulation was a lot more work than I expected…. Everything that goes inside the walls has to be in place. Once the foam is in there is no changing or adding things. I had a big list.

The insulation guys showed up! They set up fans to ventilate and got to spraying. The two part foam expands and cures in place after its sprayed. Its closed cell, wont absorb moisture, and adds a lot of structure back to the truck, it glues itself on very very well….

Once they are done spraying, it looks like a very messy frosting job on a cake, then the dirty part starts, they grind it all back down flush to the furring strips we added. Two guys with grinders makes a lot of foam dust and chunks.

After grinding it smooth they came back to make sure no spots were too thin and nothing got missed. It immediately made it not sound hollow inside any more. I need to come back later and insulate under the floor. Its something I will do myself later on.

We ended up with R 11.5 in the walls and about R 28 in the ceiling. Its nicely insulated.

Now that the truck and box are connected its time to make it feel more like a livable space, I need windows! The windows were ordered from Motion windows. They will make any size or shape you need. I ordered all of them double pane, this was the big one for me. A bit of insulation value and they don’t fog/drip quite as much. They all also open, and have screens, which should help a bit as we don’t have any AC.

I started with the Door, it was an ebay special, lots available there, but the UPS guys definitely had their way with it. It will still work, just some dents around the edges.

Hole was cut with a skill saw on the straight parts and a jig saw for the curves.

Door was installed with polyurethane caulk and stainless screws. Gives some scale to the truck. That is an 8 foot ladder…..

That was the easy one, now onto windows. The windows have a 3″ corner radius, I used a 6″ hole saw to make the four corners, then connected the holes with a skill saw for the straight lines. They are sandwiched together with the inside panels, so I can only temporarily install then before the inside is done.

 

The tape keeps the window in place and the water mostly out. There is one big window where the dinette is, one in the kitchen, and one above the bed. Hopefully that’s enough venting. I wanted as much natural light as possible, but had to balance cabinet/storage space as well.

Two windows you can see here, and a little preview of the next chapter, furring the walls and ceiling in.