As steel framing specialist for the tiny house industry, we’ve been uniquely positioned to build on customers' trailers from all across the nation.
Most Tiny House builders find one trailer manufacturer and stick to them. Others have gone the route of designing their own tiny house trailer and sticking with that. There are also a handful of trailer manufacturers out there who, although they may produce high volumes of trailers, really only experience their own trailers for the industry.
Volstrukt's Zac Siegler takes a look at three different types of Tiny House trailers.
In the last year, we have designed and manufactured lightweight steel frames for over one hundred different trailers. That puts us in a good position to offer some objective insights into what makes a good tiny house trailer.
We recently erected steel frame kits on three different types of trailer. Before they were all delivered, we took a quick look at each; a converted utility trailer, a gooseneck and a custom tiny home trailer. In this video, Zac Siegler takes a look these three types of trailer to point out some of the key feature and differences of each.
Converted Utility Trailer
If you are on a budget, it is possible to build a tiny house, or tiny business on a modified car hauler or utility trailer. One of the biggest drawbacks is the width these trailers offer. We design frames that maximize a tiny house's footprint, and with a road standard width of 8' 6", we like for our frames to be 8' wide, leaving 3" on each side for sheathing and finishes.
This customer's converted car hauler was 6' 11' wide, which makes for a very narrow tiny house. So, steel flanges were added, providing additional width and a better base to anchor the steel frame.
This trailer also came with an existing timber deck, creating a difficult situation for the installation of subfloor material and insulation. This will require the client to take a different approach to creating a cavity for insulation beneath her finished floor.
The front bar needed to secure vehicles and other loads is not needed when a tiny house is the only load it will ever have. The bar is extra weight, and impedes access to build-out the front elevation of the structure on board.
We run into a similar barricade when building on a Gooseneck trailer. Special attention must be paid to the bulkhead area at the front of the trailer during the framing and finishing process. It’s important to provide some extra space between the framing and the bulkhead to allow for structural sheathing and finish cladding to be installed. Something to think through when planning the build.
Don’t let this scare you! A gooseneck is a great solution to gaining extra floor space in the platform above the tongue of the trailer.
The gooseneck trailer we have in this week is a 28' + 8', which means in a 28' long trailer there is an additional 8' of length on the raised platform. This also means that goosenecks tend to have a step-up in structure using materials such as steel C-channel in their construction. The challenge with C-channel construction is that it leaves only 2” of heavy steel for the wall framing to be anchored to. Most walls are 3.5” - 5.5” wide before any finish materials. The recommended attachment/anchoring detail requires a ⅝” bolt to go through the center of the wall framing base plate and into the heavy steel of the trailer. This is challenging without the complete 3.5” width of heavy steel to drill/anchor through.
Stepping up to a gooseneck typically comes with better specifications, including axles, tires, structural wheel wells and jacks. On this model, we see 2 x 8,000lb axles with G rated tires and standard connected jacks - which work well when raising and lowering the trailer when hitching, but are not really designed to achieve 4-point leveling of your floor system before building. Make sure that the Gooseneck trailer you choose comes with jack points and piston jacks at or near the 4 corners of the trailer to allow you to level your work surface.
Structural wheel wells are a key feature in tiny house trailer design. First and foremost, they help combat any flexing that might be experienced while driving the trailer down the road. This helps to ensure that the space between your wheel wells and the wall system is properly insulated won’t wear away over time. Also, many tiny house designs have utilized the structural wheel well as a tread plate for the entryway door. A non-structural fender would collapse almost instantaneously in that scenario.
Custom Tiny House Specific Trailers
As the tiny house movement has grown into a market, so too has the availability of trailers designed for tiny houses. Our customers bring in trailers from most of the custom Tiny House trailer providers, which each have their design features and drawbacks.
With any trailer, thermal bridging remains one of the biggest challenges. The issue of heat transfer in steel framing is one we discuss often, but is also one that the building industry solved many years ago and there are many ways to properly sheathe and insulate a lightweight steel frame. How a frame connects with a trailer is where the thermal bridging focus needs to be!
The first thing to notice about the custom Tiny House trailer we have with us today, is it's lower profile. Architecturally, this makes a big difference to final design of the tiny house; more house, less trailer! The lower profile also allows for a different approach to the floor and deck, where a well thought out deck offers greater flexibility in running services through the floor, and creating a gap between the frame and trailer edge to help mitigate thermal bridging.
This trailer also addresses another unique challenge of a home on wheels; weatherproofing. Houses typically address water ingress from the top and sides, but not the bottom. You’ll notice the steel flashing within the floor pan which helps to combat water traveling upwards into your insulated floor system. Towing your home in a storm means ensuring the torrent of water attacking your structure from below is something to remember.
So, there we have it. A quick look at three types of trailer from the perspecutive of the Tiny House movement's lightweight steel framing specialists.