Trailer Details

The foundation of our tiny house is kind of important.

We settled on a 24 foot bumper pull trailer that is going to be 8' 6" wide when finished (the max legal width without a permit), but there were still many factors we needed to research. First off, we threw out the idea of building the trailer ourselves. Neither of us know how to weld; and even if we did this is the one thing we'd rather leave to the pros. So, we started researching trailer companies.

We compiled a list of trailer companies from referrals and our own internet search. This list can be seen on the "Trailers" tab of our tiny house spreadsheet. We wanted to go with a reputable company, but price point was also important since it is going to be our largest purchase. The two companies that stood out from the beginning were AAA Trailers in Paris, TX (now selling through Centerpoint Trailers) and Tiny House Basics.

AAA Trailers was recommended to us by a couple local tiny house DIYers we met at the 2017 Tiny House Jamboree in Arlington, TX last October. It looked like AAA Trailers would be our cheapest option when factoring in delivery cost (which was Free.99 because we are close enough to pick it up ourselves), but they were not a tiny house specific trailer company. It sounded like they had done a few tiny house trailers; but that most of them had been gooseneck trailers, and we had decided on a bumper pull trailer.

As for Tiny House Basics, they were the cheapest out of the tiny house specialty companies on the list. We didn’t know a whole lot about them, so Drew scoured their website, watched all their YouTube videos, and went through all their Instagram posts. We concluded that they seemed to know what they were doing and would provide a quality product. They also provided plenty of optional features and were willing to do all kinds of custom work.

The Tiny House Basics trailer, with all of our added features and the delivery from Alabama, was a little more expensive, but because they were a tiny house specific company, they became the front runner. We had a few specific questions, so Drew decided to email them directly. They were very responsive, answered all our questions, and were very patient with us (Drew had a LOT of questions). And that made our decision to have Tiny House Basics build our home's foundation. After that we just needed to nail down what options and custom work we wanted on our trailer.

Some of the trailer options/customization we knew we wanted: drop axles, scissor jacks, and the location of the wheels (based on our weight and balance calculations in my previous post). The additional options we weren’t completely sold on: an extended tongue, flush crossmembers, or welded-on under sheathing.

After a brief discussion, drop axles were an obvious choice. Because we have lofts in our floor plan, every inch of extra interior height helps. Drop axles lower the deck height by about 4 inches, which will give us that much needed room for the interior height. Remember, the max height of the house when towing is 13’ 6” without a permit. The only con of the drop axles is the increase in wheel well height by the same 4 inches, but in our plan the wheel wells will be inside the kitchen cabinets, so this is not an issue.

Scissor jacks were another no brainer. Unlike a normal foundation, we need a way to level out the house and keep it level. There will be one jack welded to each corner of the trailer that we can adjust to get the trailer stable wherever we end up parking. Also, this option was very cheap compared to the prices for scissor jacks we’d seen elsewhere.

The extended tongue wasn’t really that hard of a decision either. In our floor plan we envisioned an outside storage “shed” (it will be a tiny house sized shed) sitting on top of the trailer tongue. The stock tongue is only 4 feet long, which doesn’t leave a whole lot of room for the storage shed when you start taking into account the space needed for the ball coupler and the tongue jack. The extended tongue option adds an extra foot to the tongue and will give us plenty of room for our storage shed. That extra foot also helps us out with our weight and balance in being able to move our wheels further back and more under the kitchen cabinets.

Now onto the flush crossmembers. This option was dependent on how we were going to attach our subfloor to the trailer. Tiny House Basics has a pretty good description of the differences here on their website. Just focus on the crossmembers in the pictures on their website though, our trailer is going to look a little different. They first go over installing the floor with flush crossmembers and then without. Both examples are without welded-on under sheathing, which we will get to in a minute. Basically the difference is, are we going to attach the subfloor directly to the metal crossmembers (flush crossmembers) or drop in a wooden subframe and attach the subfloor to it (no flush crossmembers). If you’re anything like us, it seems like win win to go with the flush crossmembers. You eliminate the step of creating a wooden subframe and the subfloor will be more rigidly attached to the trailer (instead of attached to a wooden subframe, that is then attached to the trailer). Although there are two reasons why you may not want to go with flush crossmembers. The main reason against attaching the subfloor directly to the metal crossmembers is the increased thermal bridging. Thermal bridging is when heat is transferred through an object of least resistance, and how well your house is insulated depends on how much thermal bridging you have. Now of course we are going to put some type of insulation below our subfloor, but every 16 inches there is going to be either a wooden 2x4 or metal one. The speed which metal conducts heat is much greater than wood, so the thermal bridging is greater with the metal 2x4’s. This increased thermal bridging will decrease the R-value of our floor substantially. The other reason against flush crossmembers is the worry of condensation on the metal creating a mold issue where it touches the wood subfloor. Although that worry can be solved with a vapor/moisture barrier in between the metal and wood. After weighing the pros and cons of flush crossmembers, we finally came to the conclusion that the ease of construction and rigidity of the subfloor out weighed the decrease in R-value. We would hopefully minimize the heat loss through the floor by putting a skirt around the trailer when we are parked.

Once we decided to go with the flush crossmembers, the welded-on under sheathing made sense for two reasons. First, it would take the difficult and laborious work of attaching the metal sheathing to the bottom of the crossmembers as seen in Tiny House Basics write up from earlier. It would also give us more room (about 2-3 more inches deep) to put insulation, increasing our R-value for the floor. This is because the welded-on under sheathing is attached to the bottom of the main 2x6 beams of the trailer, not the bottom of the crossmembers as shown in the Tiny House Basics write up. As a bonus, aesthetically it will look better and be a cleaner finished product. The only real downside to the welded-on under sheathing is the cost, but we decided that it was worth it.

So now that we've walked you through our thought process on designing our trailer, here is the closest example I can show you. Our trailer will look a lot like this one, except ours will only be 2 axles, will have drop axles, will be wider, will have a longer tongue, and will not have the hole for the deck.

Sorry for the long post, but just wanted to cover everything we went through!

Trailer Is Ordered!

So yesterday we put the deposit down on the trailer from Tiny House Basics! It should be delivered to Abbie's parents in 3 to 4 weeks. Since Abbie was talking trash on me in her last post, I thought I would show you what I was up to. Here is a link to the spreadsheet that we have going for keep track of all things tiny house.

There is a tab called "Weight & Balance" and one called "Flipped Weight & Balance." We originally wanted to have the bathroom on the hitch side of the trailer, but based on the weight and balance the fender would have fell where we wanted to put the door into the tiny house. We could have worked with this, but in the end we decided that it would be better to flip the tiny house around and have the living room on the hitch side. This put the fender under the kitchen counters where we wanted it.

To decide where the fenders (wheels) needed to be placed, I had to do a little research. I knew that you wanted to make sure that you had weight on the tongue of the trailer (more weight in front of the wheels than behind them), but I didn't know what the sweet spot was. After a little googling it seemed like somewhere between 10% and 15% of the weight of the trailer should be on the tongue when it is fulled loaded. I decided that since we are going to have such a heavy tralier (~12,000 lbs) and that class IV and V hitch ratings have max tongue weights of 10% of the max gross trailer weight, we should shoot to have the tongue weight be between 10% and 12%.

So we created a line item in the spreadsheet for everything that would be on the trailer once we were done, gave it a weight, and gave it a center of gravity (CG) from the front edge of the trailer deck. That way we could get the final trailer weight and CG. Then using some math we could figure out the ideal place for the wheels to give us between 10% and 12% of the weight on the tongue. We went with the location required for 11% of the weight on the tongue, just so we would have some play on either side since the weight and CGs of the line items were just best guesses.

I hope that at least kind of explains our rational on deciding the location of the wheels and explains the importance of calculating the weight and balance of your tiny house. I'll create another post soon that goes a little bit more indepth on the trailer and why we choose all the options that we did.

Buy the trailer already!

Weights and balances engineer over here is checking our design for the 100th time.

But he has assured me that we will put down the deposit this weekend. Maybe if we put a wager on it, then he'll feel the pressure?

What's the bet babe?