Installing a Trailer Ceiling

Now that the major part of the heat and humidity is (I hope) nearly behind us, I was finally able to get out to the cargo trailer and get the main ceiling installed.

Due to the insulation being slightly thicker than its nominal value...by roughly an eighth inch...I was debating using the same kind of 3/8ths-inch plywood on the ceiling that was on the walls of the trailer, but the price was more than double the price of 1/4-inch luan, so the latter won out.

But the steel roof bows of the trailer were now shy an eighth of an inch of being flush, so I simply used some scrap paneling and cut strips, which I then secured temporarily with a couple of screws in each one. The ceiling would take care of the rest.

What made this trailer hard to work with is a compound bow of the front and top. For this part, we have to deal with both the bowed front as well as the bowed top, making the scribing of accurate lines a real trick.

What I came up with is a makeshift scribe cut out of the end of a scrap 2 x 2 and a short pencil...short only because it was what I could find that would work.

My makeshift scribe for marking the ceiling.

The idea is to set the pencil half-way into the piece of wood, so that the point is as close to being even with the edge of the wood as possible. To do this, I set the pencil on the table saw up against the blade, and then cranked the blade down to where the top of one of the teeth was at the center of the pencil. Since this pencil was hexagon shaped, that was easy.. When laying on one of it's flat sides, the center is a convenient "point" on one of the sides, so it was just a matter of setting the blade even with the point of the hexagon.

The pencil tip needs to be even with the edge of the board.

The notch was started using the rip fence, and then simply bumping the rip fence over a blade width for each cut. I wasn't worried about the length of the cut, as long as the screwdriver would lay into the notch. If I wanted to get fancy, I could have clamped a stop against the rip fence so that each cut was alike, but in this case, I guessed at it.

The next step was something to hold the pencil into the notch, and as you can see, a plain old rubber band, like the kind the postal carriers use to hold bundles of mail, worked just fine.

So the next thing was to hold the ceiling panel in the exact position (except for length) that it would be in. The sides were the most important, to line up with the pencil marks I had set. At the front, it was simply pushed against the fiberglass top nose of the trailer as far as possible. To hold it up, we (my wife helped lift it to the ceiling) used a couple of handy pieces.

The front ceiling panel held in position with temporary posts.

One was an old closet rod with some extra blocking for height under it and a flat piece on top so it wouldn't scratch the ceiling. The second was a jack bar that we bought at a truck stop to put under the extremely long front end of our truck camper when it was off the truck, just so in case someone climbed into the bunk, the whole thing wouldn't tip over.

We have found this trucker's bar to be extremely handy for many things, so it was a good investment for under $30. It already has heavy rubber pads on both ends. Normally the bar is used horizontally (and maybe vertically, too) to expand between the sides (or floor and top) of a trailer to keep cargo from shifting. It isn't very good for trying to "jack" anything up, as it has very limited travel and power, but for this purpose it was great. I also used it to hold the blocking pieces up when I was installing the ceiling blocking, and it worked like a charm.

When setting the ceiling panel in position it's important not to force it too tight to the ceiling, so you can bump it around and get it lined up properly. Then you can add some extra tension to keep it there.

The next thing is to use the scribe to mark the curvature. To do this, you hold the scribe flat against the front wall, so the pencil is even with the wall, and then gradually drag the scribe from one side to the other while holding it against the ceiling. The pencil should mark the exact curvature of the front wall onto the ceiling panel.

The scribe has to be moved sideways while keeping the pencil against the ceiling.

Once the mark was made, the ceiling panel was taken down, and moved outside the trailer, and then flipped over, so the pencil mark was facing up. I then used a saber saw to cut along the line and make the contour. Normally, you wouldn't want to use a saber saw that pulls up as it cuts on a finish side of a piece of paneling, as it causes it to splinter out. But in this case, there was blocking to be added to the first 1-1/2 inches, so any splinters would be covered.

Exact curvature of trailer front duplicated on ceiling panel.

Now that the curvature was cut, there was another thing to consider. All along the top of the trailer there are wires and many "fold-over" connectors for the inside as well as outside clearance lights. Those connectors have been known to fail. In case anything would ever have to be repaired, those must remain accessible (to a point).

In our trailer, I decided to add a filler piece to the front wall of the trailer. It will attach at the bottom to the front wall, but at the top, we needed some backing to secure it. To solve that problem I used some of the cut off scraps from the ceiling blocking, and cut them down to 8 pieces 6 inches in length. They were already 1-1/2 inches thick and about 1/1/4 inches the other way, plenty to serve as a backing for the future wall panel piece.

I laid them out, keeping the front edge flush with the edge of the paneling, balanced out the length side to side, and then glued each one in place. I used a couple pieces of scrap 2 x 4 on the underside, and then used individual clamps on each piece.

Blocking pieces being glued to the ceiling panel.

After a couple of hours of letting the glue set up during the hottest part of the day, I removed the clamps, flipped the panel over, and then used my Bostitch pneumatic staple gun to secure each piece with about 4 staples... just in case the glue ever dried out or let go.

At the top of the front wall of the trailer I had debated for a long time as to how to insulate around that curved wall and ceiling. Rigid insulation board would be a real pain to fit in that space. I had some leftover pieces of 10-inch encapsulated (wrapped in pastic) fiberglass insulation from when we did the house, so I decided to use that. It was thicker than I needed, but I didn't feel like taking it all apart to separate it into layers. I had one batt that was four feet long by 2 feet wide, so I did cut the width down so it would fit without bunching up too much, but I left the rest as is.

While the panel was down, I measured carefully from the front edge of the scribe (while holding it against the front wall), and got the measurements for the fan opening, as well as the last roof rib I needed to be centered on to secure the rear end of the panel. The fan, being centered, was easy enough to figure the other way. I made the fan opening cut with the saber saw, this time being careful to score just outside my pencil marks with a utility knife, so as not to splinter out the edges.

For the end cut, I transferred the mark to the back side, and then used my circular saw to make the cut, so that any splinters would be pulled toward the back side of the panel. I also used my 6-foot aluminum straight edge clamped to the panel to guide the saw in a perfectly straight line, making a finish cut as good as any factory cut.

The front panel was installed first, and screwed into the steel roof bows using the special screws that were so hard to get (see the previous post). Along the edge, I again used the Bostitch staple gun to secure the edges to the edge blocking as well as to go around the fan opening.

The second piece, to cover the rear half of the ceiling, was much easier, as the back of the trailer is straight across. To keep a tight seam where the two pieces meet, I measured the fan opening from that point, and then cut the opening and the rear cut the same way as was done on the front panel. This one also only needed one temporary post to hold up, as the back edge went over the rear door torsion spring. That part will all be hidden within the rear storage compartment as time goes on so it doesn't have to be real fancy. I did add one center piece of blocking between the last rib and the rear bulkhead, so that was used to staple the rear section of paneling above the torsion spring.

So now, the hard parts that consume a lot of time are all done, and the ceiling is finally in position and secured. 

The new luan ceiling finally done!

The curved ceiling edges on both sides will be fitted with sheet metal panning, and then cabinets will hide most of that, except for three places, (1) above the entry door, (2) inside the closet, and (3) above the head side of the rear bunk. The edge blocking at the sides of the main ceiling will be the anchor points for the fronts of the overhead cabinets, and any sheet metal will be behind and above, and won't be seen unless the cabinet's doors are open, Since everything else in the trailer will be eventually painted white, I plan to use pre-finished aluminum flashing material to form the curvatures and then it will be stapled in place along the edges. Where exposed, a piece of thin lattice will cover the joint.

Nothing more needs to be done with this part. I still have to obtain the correct adhesive caulk to seal the roof around the fans when I install them, but that can be done anytime now. We have to make a run to Batesville to get the commercial tile for the floor, so I will probably get the caulking at that time. The luan for the floor underlayment I can get locally, so that isn't a problem.

At this point we have "maybe" two days of 90+ degree weather yet (hopefully the last we will see this year), and then we have an abnormally cool front coming in, so now is the time to get busy on these outside projects.

Once the floor is down, I should be done with large sheets of plywood. Most of the rest will be much smaller pieces to cover the 1 x 2 cabinet framework, and I figure on doing most of that inside the trailer. Once the fans are in, I just need some temporary lighting and I can work out there all winter. A small electric space heater will be enough to take the chill off later on.

I probably won't even need to use the new air conditioner this year, but I needed it to be able to build the front couch around it, and create the necessary baffles under the couch. That will be the next thing after the tile floor is in. But it will be good to have it operational for next spring after it warms up again!

OK, now that you see how it's all coming together, what do you think? I know everyone has an opinion, so let's hear it. If not an opinion, how about questions? I'll be glad to answer anything on your mind.

Thanks for reading!