tiny house bracket system

Attaching Trailer to Tiny House

Promotion at work, massive amounts of rain, and loads of trips means I didn’t get nearly as much time as I’d hoped I’d have had to work on the tiny house.  On the plus side…..I was able to take that time to work on a very important (and earlier missed) step…..properly attaching the Tiny House to the Trailer.  If you read my earlier post here you can see the woefully inadequate brackets I used to connect the trailer to the subfloor.  Well, they weren’t inadequate for that purpose….just inadequate for attaching anything MORE than a subfloor.

Social – YouTube

In a previous post while standing in front of the house as I had the house tilted a bit forward I realized that aside from those small L brackets…nothing else was holding the house to the trailer’s metal components….slightly scary.  On the plus side….nothing bad came of it and I was able to fix it.  I tried finding posts from other Tiny Housers with little to no luck.  I found a couple of mentions but nothing concrete about how you can:

  1. Support the cantilever (overhang) where the weight of the entire house frame on the sides is directing forces down into the subfloor that overhangs the trailer by 5.5″ on each side
  2. Attach the trailer to the frame like in typical construction where the frame is attached to the concrete foundation

So I began with looking at how a typical house is attached to a the concrete foundation.  With quite a few variations I was able to narrow it down to one type that would work in my case, 1/2″ lag bolts through the bottom sill:

bottom sill attached to foundation

So, Lag Bolts through bottom sill for the win!  They need to be placed about every 18″ to properly secure the frame to the trailer.  The only problem is that the sides of the tiny house overhang the trailer so any connection would require a bracket of some sort….a very heavy duty bracket. Note….if you buy the lowrider trailer from Tumbleweed….this isn’t an issue as their trailer doesn’t need support brackets, you’d connect directly down through the trailer. I searched high and low for said brackets but couldn’t find any that had adequate shear and load bearing strength.  I decided to have a custom order made.  I went with shortrunpro.com and designed the brackets in Sketchup and sent them over.  Initially I’d designed them with side walls since I was thinking about them only being 1/4″ in thick but after talking with the guys at shortrun I found out that I wouldn’t need the sidewalls if I just went with 1/2″ thick cold rolled steel rather than 1/4″ angle iron.  The brackets are 1/2″ thick cold rolled steel with holes drilled at precise measurements to fit my needs (yours might be different). Total cost was around $850 at the time I bought these with a few weeks of work to get them done.  Below are the pictures of what I sent to Short Run Pro.

What they created after quite a bit of awesome consultation was one solid piece….much stronger than my idea (and a hell of a lot cheaper).  Those along with the 10″ long (and 3″ long) 1/2″ thick lag bolts/screws/washers created the tiny house subfloor and frame attachment system I’d need to make this a win.

Drilling the holes through the subfloor was no peach as I had to drill through the bottom sill of the frame, the subfloor (3/4″ plywood, insulation, and metal flashing) and then the 1/4″ thick hardened steel of the trailer.  Different drill bits were utilized and I even had to buy a new drill to fit the 1/2″ cobalt drill bit I’d bought. Drilling through the steel required lots of patience, loads of oil, and did I mention patience?  In the end I was able to knock it all out and I came away with a fantastic support for my tiny house while firmly attaching it to the trailer! Look at the difference between those old puny 1/8″ or 1/16″ thick ones I had on there….what was I thinking?

tiny house trailer bracket


And here you can see how the front and back portions of the tiny house were attached directly to the trailer (no brackets needed):



More to come on all the fun I’m having building a tiny house!

Leave a Reply