The Subfloor: The Most Unexpectedly Lengthy Part Of Building

We bought our trailer. Picked it up. Drove home feeling super empowered and ready to work.

Then came the subfloor. The step that had a us feeling like our home would never be more than a trailer bed...maybe just lots of endless and often failed attempts to drill through the strong steel of the trailer. (So. Many. Broken. Drill bits.) 

The Practical Recommendations

If you're not actually building a tiny house any time soon, totally skip this section of read on from the next header. You might get bored.

We didn't know how self-tapping screws worked, exactly. We learned from the Tumbleweed instructional DVD that self-tapping screws = no pilot holes. (That didn't exactly pan out.) I'm sure they would've worked just fine for drilling wood into wood, but for pressure treated wood into steel, it was almost impossible. We ended so many work days saying, "Next time we'll REALLY be done with the subfloor!" But then we still wouldn't finish the next time.

The point is, when doing this first step of outlining the trailer frame with 2x4s to give the walls something to hold onto (which our plans required), you'll probably have to drill 2-3 increments of pilot holes for the self-tapping screws. We started with a teeny tiny drill bit which would eventually make its way through the steel (if it was relatively new, not bent yet, and the drill had full battery). We ended with a drill bit that was the same width as the screw shaft and smaller than the head of the screw. Even after this method, the screws sometimes refused to go through. But persevere! It's necessary and definitely character-building. 

What even is a subfloor?

One of the most awkward parts of building a tiny house is that we have no idea what we're talking about half the time. We sometimes know what we're doing, but don't usually know the proper construction terminology to refer to the steps of building. 

Several adults that we've talked to about our project know all the words. Whether they're pros or home tinkerers, we end up straining to follow along, because we don't usually absorb the terminology of each step until after we've moved on to the next one. 

So, we'll do our best to explain each step in easy terms! (Goodness knows that's all we can do, anyway.) The subfloor of our tiny home is several layers: a utility trailer, which is steel and has steel joists (bars) that go across the short way of it. Between the joists we put 3.5 inches of foam insulation, so our toes don't get cold. On top of the joists we glued sill sealer, which is a thin pink strip of foam, so that there aren't random cold strips under our floor. Then we topped the whole surface off with sheets of tongue-in-groove OSB - or, sheets of compressed, glued wood chips. The tongue-in-groove part means that they fit right together so that there are no gaps when we were done. We nailed these sheets to the 2x4s we'd screwed to the outside of the frame, and screwed the sheets into the places where they overlapped with the metal joists. 

Subfloors Are Important

While this step was pretty frustrating at times, it was worth it. While the trailer itself is the tiny home's foundation, the subfloor is the next-closest part to that. It's one of the only parts of the house that's directly attached to the trailer in so many places. 

You can do it! Don't give up!

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