It was seem as though the options for building a floor for your teardrop camper would be relatively straight forward, but you actually have quite a few options here.
The name of the game when building your camper is weight and space. It’s a balance, and if you want space, you almost always have to sacrifice weight. Materials used add strength, but it also adds weight, but there a payoff of space. One of the most helpful quotes that I heard when I started researching a teardrop camper was, think airplane, not tank. This is the key to saving weight.
When we started to look at the floor component of the trailer, we decided there were a couple different options that we would like to explore. Each has it’s own benefits.
1. A flat piece of plywood
This is the simplest, and definitly the most easiest route to take. Most folks that use this method (through my research) use solid 3/4 plywood. Either ACX rated, or Baltic birch. ACX is a little cheaper in most places, but baltic birch is a little more stable and will end of a little flatter and easier to work with. Either way, you will end up with floor that is plenty sold enough to walk on, and definitely solid enough to sleep on.
This is the fastest way to build a floor.
2. Sandwich floor construction
This is the method that we went, mainly because it ends up being a little bit lighter than the sold floor method. Having said that, it took probably 3 times longer than it would to have just thrown down a sheet of plywood and called it a day.
There are many debates over this but this is the method we took.
1/4 plywood top + 1 by (3/4″ actual thickness) middle framing and foam + 1/4″ underside plywood
When I first read of this method, I thought “yeah right”, but you will be suprised at the strength of this “stress skin”method of framing. Because ALL of the components are glued and screwed together, this entire unit functions together to for a rigid panel. Even with our 6 ft wide trailer, this is very strong (and light weight given the size).
This is the slower of the two methods, but were preferred it for weight savings to the the “extra large” size of our build. It took a while to do it this way, but I’m glad we did, and would probably do it again.
One tool that was a huge key begining here, and was used throughout the rest of the build.
The Kreg Pocket Hole Jig
PRICELESS! We used this thing over and over to join two (or more) piece of wood on the same plane. A MUST HAVE in my opinion.
Once we were finished with the structure of the floor, we coated the top of our floor with a couple coats of a good spar varnish and the bottom with a roof tar sealant material (Black Jack). There are a number of different brands, but we chose to use black beauty on the bottom and Cabot spar varnish on the top. There are a number of other coatings for the bottom. I have seen others us Henry’s and also, a black fence post paint. I have even read of an epoxy resin with cloth. I think any of these methods will work, this is just the one that we happened to choose.
The purpose of the bottom undercoating is to keep the water out (obviously), and purpose of the varnish is to keep the trailer sealed from any moisture that may collect on the inside, or from any spills that might occur. The “spar” part of the varnish is the key, in that it makes it UV resistant so that it is less likely to break down over time.
Since we used the “sandwich” method for our teardrop floor construction, I will talk about foam. There 2 basic types that you will come across in your local home center.
1. Polystyrene – This is a little more flexible, and thus not quite as strong. It is the foam that looks like a much of tiny balls fused together, and is covered with a reflective foil material. The one we found was a little less than 1/2 inch, more like 3/8. We used it in a couple places, but most of our construction utilized the foam below.
2. Extruded Poly Styrene (XPS) is what I used on most of my teardrop build. It is much more dense, and as a result is stronger. Not to say the other won’t work, but I just like the XPS a little better. It cuts easily with a cordless circular saw, and is a true 3/4 of an inch.
How did we keep this all together ? 2 materials
Tightbond II and PL Premium adhesive. The tightbond we used on the wood-wood surfaces, and the PL Premium on the rougher and foam surfaces. PL Premium is a poly based watertight adhesive. It is like liquid nails, but it plays well with foam, it’s water resistant, and it is TOUGH. Once things are glued together with it, you will break them before you break the bond it has with the material.
For the top layer we used 1/4 birch plywood from our local home center. It was a little $$, and honestly, you never see the floor. We used BC grade 1/4 on the bottom. If I had it to do again, we would us the 1/4″ BC grade on both to save a little $$.
After all was said and done we had the floor complete. It was (eventually) attached with 5/16 carriage bolts, thought the 1x material into the frame. I think we used about 10-12 of them. Really you could use self taping screws. I won’t budge when it’s done, and it is much more stable than you think. Like most things, we over built them. Next time… self taping screws.
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