Case Study: Tiny House Trailer Design

A good foundation is important in any new venture, of course.  And, that is definitely true with the foundation of a Tiny House!  For a Tiny House on wheels, the trailer IS the foundation — both literally and figuratively.  What is more important than getting the foundation right?  So, start with the best tiny house trailer plans.

Several of our customers who build tiny houses understand this, and they come to Synthesis for engineering and design so their new “Tiny Homes” have a solid foundation.  They want something different, something more stable, and something stronger for their foundation.

At Synthesis we’ve designed several Tiny House Trailer Foundations that include some pretty cool and unique features.  But, it’s not just the “cool” things that make the designs good.  It’s the integration of cool with the first and most important need for a solid foundation.

This is a “Case Study” we show some of the thoughts in the design of a better trailer for Tiny Homes.  Come with us, and follow along with the process of thinking it all out.  This is how we design tiny house trailer plans.

What Makes A Tiny House Trailer Design Different?

The first step with any design is understanding requirements — especially unique ones.  You can see our emphasis by reading Product Requirements in the popular Product Development Process Article.

Here is a partial list of  things that are important for Tiny House Trailer Plans design comparing to other types of trailers:

1. For a Tiny House Trailer, the load is the house.  Once it is set, it stays, but it’s not static.  (Utility trailers, car haulers and most flat beds have periodic loading — which is different.)
2. Loading is mostly at the edges where the walls attach.  Some loads are in the center, but the weight is not even over the bed.
3. While most trailers do sit for long times, the Tiny House is usually active even while it sits.
4. When the Tiny Home trailer sits, it remains loaded.  (Most trailers sit empty, and typically they store undisturbed.)
5. For most trailers, some flex is no problem rolling down the road.  As potholes and bumps, occur they flex slightly.  A little flex is fine for a car hauler, because the car doesn’t care.  However, in a Tiny Home, cracks appear in walls or ceilings, and windows can twist slightly and break.  Stiffness is important.
6. Every inch counts, so foundation trailers need maximum width — full size — within legal limits.
7. Maximum square footage and vertical space make long low trailers that need stiffness.  Thinking about tandem axles or sometimes triple axles is important.
8. Finally, a low bed height is good on many trailers, but the Tiny Home is unique as the bed is the start of the floor.  Tiny Houses often push legal limits for height as they include lofts and vertical expansion.  Gaining a few inches with a low deck height is very desirable.

Designing To The Requirements

In summary, the trailer must be super stiff, especially for edge loads.  It must be stiff for the always live loads with activity in the house; wind, snow and other environmental conditions.  The foundation built from tiny house trailer plans must be strong to hold a full load all the time, and to travel flawlessly.  Finally, it must allow all sorts of varying loads like tanks, batteries and storage.

Oh, and a Tiny House trailer design must allow all sorts of floor plans and options with a low deck height to allow customers a roomy loft if they want.  Most Tiny Homes are unique, not only in floor plan, but also in construction and in ways people live.  A great Tiny House Trailer must handle all of it — as well as the normal functions and towing chores.

Truly, designing well for a Tiny Home has another level of thought and greater need for attention to detail.

Conquering The Floor

In the process of study and design, we include the obvious like drop axles.  But there is more to it, and we include some clever ideas of our own.  Most important is a method for #7 above, which is a very common concern.  “How do you get the most vertical space for a Tiny Home?”  Or, stated more directly, “How do you get the house floor as low as possible?”

Our answer?  Integrate floor supports right into the trailer frame.  That is not so unique, but we also combine it with making the frame both easier and faster to build.  Interestingly, our method also assures a better, straighter and flatter floor.  So, what’s the trade-off?  There are two:

1. First, since the frame of the trailer integrates with the house, it moves some of the “house” weight to the trailer.  It makes the trailer a little heavier, yet in the process, it makes the house lighter.
2. Second, the build process has an advanced technique for cutting for the main beams.  At Synthesis, we often use laser or waterjet cutting to build specialty manufacturing machines.  Since we know the value, we bring this technique to the Tiny House Trailer.  It makes construction easier, more consistent, and gives a lower house floor.

Having floor supports built into the trailer frame reduces the floor height (effective a lower trailer deck height) by approximately 6″.  Additionally, it gives superior stability, a flatter floor, and better wall anchoring.  This is part of the new tiny house trailer plans.  Read more about walls below.

Addressing Space in the Tiny House Trailer Design

As a side note, if space is a concern, our plans have more than just a low floor.  The lower floor allows more vertical space, it’s true, but that’s not all.  Using the full legal width is another.  Our plans have frames that are 1″ less (each side) than the legal limit.  That allows outside finishing, like siding, to extend over and cover the frame edges within the limit.

Yes, it’s supposed to be tiny, but there is nothing wrong with using the full space for comfort.

The Right Support In The Right Places

Another big issue we tackle is perimeter support for the walls, and anchoring the house to the trailer.

Perimeter

Designs by Synthesis analyze the frame with loads primarily at the outer edges.  Our designs don’t leave perimeter loading as a side note, it’s part of the fundamentals.

In a house, the walls are and hold most of the total weight.  Certainly the roof, the loft, snow and wind loads, hanging storage, shelves and other forces come to the frame through the walls.  This is why we place a strength priority on the tiny house trailer frame perimeter.  And, we anchor the walls securely for a truly strong foundation.

By using tools like FEA fueled by engineering experience, we use cross members designed to carry these loads.  It’s not an afterthought.

Anchoring

A typical Tiny House trailer often has threaded studs welded to the frame as anchors for the walls, much like a standard stick built house.  It’ a great idea, but it has one rather important shortfall — wood changes over time, especially with weather and movement.  Yes, movement, and trailers introduce a lot of that.

I learned this lesson working for farmers where I grew up — bolting to wood often requires re-tightening.  While the weld studs on trailers look like a great idea, and when they’re new, they feel like a great idea, there is no way to re-tighten over time.  (Maybe cutting holes in the walls to find the studs and tighten things?  I don’t want to punch holes in the walls to search for studs, do you?)

The solution is simple.  Set the anchors in the walls, solid to the footer board, and allow access to clamping bolts from underneath.  With anchors in place, you simply go around the trailer frame and tighten each bolt.  This way, the house is always solid to the trailer.  It’s simple, and the details are in the plans.

All The Way To The Ground

The frame is certainly a major component of the strong foundation.  So are the supports for the frame — like the axles and jacks and tongue and other supports.  The tiny house plans dictate square feet and the full size for your tiny house living.  From that we work out a tandem axle or a triple axle configuration.  It does depend on where and how big the loads are.

Finally, the corner jacks for trailer stabilization when parked.  Don’t put the jacks right at the corners, rather bring them in just a little from the ends for better load distribution.  It’s a mistake common with tiny home builders.   Oh, and don’t forget to put something wide and stout under the jacks so they don’t creep into the ground.

Tiny House Trailer Plans Available

The end goal of the exercise is an awesome Tiny House Trailer Plans Design — one that has a sturdy foundation for building a house to last a lifetime.  Secondly, get the plans into the hands of those building Tiny Homes.  With our engineering tools and expertise, we’ve created plans that are designed specifically for the Tiny Home market.

This case study ends with some really great Tiny House trailer plans are now available to everyone.

If you’re thinking about joining the Tiny House movement, we have something special for you.  At Synthesis we have awesome DIY plans, and now, and expanded line of Specialty Trailers with these tiny house trailer plans.  They are sold through  MechanicalElements.com, and are available now for immediate download.

Engineering is what we do, so these new plans are complete.  They include a balance for all the requirements.  The result is a heavy duty trailer ready to carry your new house.

Don’t settle for building your house on a car hauler or a large utility trailer.  We don’t guess at loading while thinking it will be good enough like some people on YouTube and around the internet.  Instead, we do the engineering.  When you invest in building the house, make sure to start on a solid foundation.

Good Luck with Your New Home Trailer Project.

Share the Article: