Last weekend we continued the interior installation of a weekender LQ after letting things languish over the winter. Last Fall we installed the floors and knee wall. This Spring, the owner had already sistered wood studs to the aluminum studs, when we started again.

The next step was to fabricate wooden ceiling joists from 1 x 4 pine. My trailer has a flat inside finished surface which the owner wanted to duplicate. The roof has a slight arch. By making a template of luan, and screwing three boards together at a time, I was able to cut the curves on my bandsaw and quickly fabricate the joists. Where the emergency egress vent and air conditioner will be installed, I made the joists from 5 /4 Ash for additional strength.

Using my smaller air stapler, we then installed roll insulation to all the interior faces of the metal studs. This is a fiberglass product about 3" wide that is used for pipe insulation. The wood studs are proud of the metal about 1/2", enough space to tack on one side of the insulation. The rest was then pushed around the end of the metal stud and tacked in place with duct tape.

The owner provided 1 1/2" double sided foil faced rigid insulation. We measured between the studs, and I cut this aprox 1/8" wider on my table saw. It was then pressed into place with a slight interference fit. One side securely held the loose fiberglass edge that was taped into place. We spent the rest of the day installing all the insulation, finishing up with metal tape on all the joints. All of the little corners and open areas around the windows were sealed with spray foam.

The next day the owner started the installation of the horizontal boards. (On a barn these are called purlings and girts. Don't know their names in this context) I went into the shop and started working on the walls and door. I ripped a 2 x 4 into half inch strips and made the inside frames for two walls. I then cut Luan plywood to fit each side, and spraying on a water based wood sealer to both sides. Gluing up the hollow core walls and using a pin nailer to hold things together until the glue dried, I soon had two strong, light weight walls. About 1" thick, light and rigid, these formed the wall at the end of the galley counter and one of the bathroom side walls. The area in between will be a wall storage cabinet, sized to fit stock WalMart plastic drawer units.

The front bathroom wall and door were framed with 1" Ash strips and again surfaced with Luan. The Ash and 1 1/2" finished thickness, ensured there would be adequate strength for both. These will not be installed until the bathroom is more finished. My LQ's bathroom has a shower base, curtain and shower head which we don't use. We have a cowboy shower in the first stall which is more convenient. On his trailer, this bathroom shower will not be installed and a similar cowboy shower will be installed in the first stall. In his bathroom, a large wall mounted clothing cupboard, will be fabricated and fitted along with two adjustable boot/shoe racks. In our trailer, the shower base collects all the foot wear and hat boxes, as the boot box is used as a seat, step and storage for water and the water pump.

This weekend we will be cutting several holes into the pristine body and roof. On the roof, there will be a vent and emergency egress exit installed over the bunk, a hole for the a/c unit, a vent fan in the bathroom, and a stack vent. On the  outside walls of the galley, we will install access/vent panels for a gas water heater and refrigerator. He will also need to have holes cut for shore electrical and water sources and exterior ac receptacles.

During this week, the owner will be roughing in the wiring and installing electrical boxes. He's using stranded 2 conductor 14 awg for the DC, and 3 conductor 12 awg stranded for the ac wiring. We will install a circuit breaker box and fuse box in the storage area besides the galley. The wiring and fuse strip was sourced from a marine supply.

When we started insulating in the morning, it was about 45 degrees outside. By early afternoon as the outside temps rose to about 50 degrees and our work progressed, it became uncomfortably warm working inside the trailer. Soon the doors were left open. The insulation makes a big difference.

Gard

If it were my trailer, I would insulate any exposed interior stud surfaces. Here's one example of why you might want to consider doing so:

Some friends are starting their DIY LQ in a steel trailer and have all the insulation up between the braces (ceiling and walls) and furring strips up. The gooseneck floor and regular floor are also insulated and then have plywood wood on top. This past weekend, they used it for camping and it was just cool enough to use the heater during the night. They told me that condensation was forming on the roof metal braces and wanted to know how that condensation would affect the wood they were planning on putting up for the ceiling. So anyone know the answer? If I remember correctly, even though they have put up furring strips, the wood will still touch the metal braces. Will the roof metal braces still form condensation after the wood is attached to the furring strips? If yes, won't that condensation be absorbed by the wood ceiling and then cause problems?

Wish I had the knowledge of, and access to, the various products used in the RV and LQ "business". Our projects could certainly be finished more easily.

Gard

gard, how true! More often than not, there is/was an easier way to do something. But when you have to "make it up as you go", things take longer and sometimes have to be redone.

But the "industry" isn't always right. Some of the DIY's will be of higher quality, if proper research is done. When I had employees, often told them, as an owner my motivation was different than theirs. Same here.

By "sistered" do you mean that the wood studs were attached alongside the metal studs of the trailer?  And, regardless of whether or not this is what the term means, where do you usually run your wiring when the wood studs are installed this way?  In my first trailer, we did the walls in this way, and the wiring was run above the walls in the curve between wall and ceiling, and then descended to the plugs and outlets. I'd like another option for the current trailer.

Also, the spray foam you used -- was it an automotive or marine type, or the household variety that expands and has a yellow shade to it?

I have a Kiefer which has those very interesting studs that are 3 sided, not 4.  It's like the interior facing side of the stud has the center cut out of it, and you can see the inside of the whole thing.  I'm wondering if I should be insulating INSIDE this hollow, or just OVER it instead. 

Sistering is a term used when a new part is affixed to a broken part, to reinforce it without removing and replacing the part. It could be a boat rib or a household floor joist.

By Sistering wood studs to the trailer's metal studs and structure, you can create a gap, and when the horizontal boards are installed, you will have enough spacing to run your wiring laterally, directly to your individual terminations.

The insulation I used, I believe, differed from A123. His I think, was the two part commercial insulation used for open surfaces. I used the spray can expanding foam type, for small cracks and areas not easily accessed.

Many trailer manufacturers use many different stud and structural shapes in their construction. Some studs are "C" shaped, others are a closed box, some are open hat sections. There are many variants.

There are many types of rigid and flexible insulations available, that can be use to cover these surfaces. There are many ways to install an effective thermo barrier. How you construct your installation will determine some of the methods you can use.

Gard