Styrofo-My-Goodness I Hate This Stuff – Part Two

June 12, 2015

Part Two of our flooring adventure!

On Sunday, after church and then saying our farewells to Chris, Anna, and the kids, Eric and I began the process of fitting in the insulation and attaching the subfloor to the trailer. Remember how I was saying that this job was so easy and everything was falling into place? That abruptly ended about 30 minutes after we started working again.

Too Tall

While Eric and Chris were setting the insulation into the trailer the day before, they noticed that the insulation seemed to be as tall or even taller than the 4 inch cross beams. We all reasonably assumed that was no big deal because A) the metal flashing that the foam boards lay on isn’t perfectly flat so of course some pieces looked taller than expected, and B) the very heavy subfloor boards would squish everything down and into place. Well, when we tested this out we realized the foam boards didn’t squish, and the subfloor rubbed against the foam making it sound like we were walking on a bunch of squeaking styrofoam coolers. Want to know what the most annoying sound is in the world? Walking on a bunch of squeaking styrofoam coolers.

We quickly realized this would not work. If I had to hear that sound every time someone moved in our tiny house, I would drive that thing off a cliff in no time flat. (Not to be dramatic or anything.) Anyway, we had to figure out the problem. The stacked foam boards were only supposed to be 3.75 inches tall, so how could they be rubbing the subfloor so badly? There was supposed to be a quarter inch gap between the subfloor attached to the metal beams and the top of the insulation….what could possibly be the problem? In yesterday’s post I spent a whole paragraph talking about how stupid construction measurements are, and that’s what you call foreshadowing, because it leads to this moment when we realized those foam boards were not the advertised 1.875 but actually 2 inches thick!!!!! And, some boards were even bigger than that! OH, LOWES’ CONSTRUCTION MEASUREMENTS HOW I RAISE MY FISTS AT YOU!

That quarter inch really made all the difference. And yes, we should have measured everything just to be sure, but we really figured the advertised actual size would be the actual size. We decided it was too expensive to buy new boards that were half the thickness, so I got to work sanding down the foam boards. I took out each top layer piece of foam and sanded it down a quarter inch. At this point, Eric and I wondered what we had gotten into using styrofoam and began dreaming that we had said “YES!” to spray foam insulation. But, we didn’t, so I sanded. And, sanded. And, sanded. And, sanded some more. Styrofoam isn’t exactly environment friendly, so to keep the foam bits contained, I had to work in “The Pit.” Trust me, it’s as lovely as it sounds. The Pit is a cut out in the floor of the garage so Eric’s dad can work under his cars in the garage without having to jack up the car. It really wasn’t so bad, except I had to hold the styrofoam piece with my feet while I hunched over to sand it down. It’s how all the professionals do it, I promise.


Too Tall Styrofoam

Too Tall Styrofoam aka The Bane of my Existence

Sanding in The Pit

Sanding in The Pit

It Fits

Finally short enough for the trailer.

By 11:30pm, all the styrofoam finally fits!

By 11:30pm, all the styrofoam finally fits!

I sanded the styrofoam from about 3 in the afternoon until 11:30 that night. (The next day I was so sore!) While I was sanding, Eric and his dad, David, spent that whole time watching TV. Just kidding! They were tackling the subfloor. We decided to use AdvanTech subfloor boards with tongue and groove edges that provide a more solid fit and a stronger floor. Eric and David were working very hard measuring, cutting, drilling, gluing, and fitting the subfloor into place. It’s really great that I have them doing the important stuff because I would have done things very differently and had horrible results. Those smarties knew to stagger the joints of the subfloor so there wasn’t a weak seam in the floor. Because of that, there was some very precise measuring taking place, and even more precise cutting. Each piece of the subfloor had to be perfectly square with the trailer and perfectly square with the other pieces. There also needed to be a 1/8 inch gap between each piece to allow for swelling or else the floor could eventually pop up and bust at the seams. No thanks on that. They also had to drill a hole so each piece could slide over every welded rod. All of these little details make the measuring so important.

Once the top layer of foam was sanded down, we took out the bottom piece and lined the edges of each channel with spray foam. Once the spray foam was in the seams of the flashing and cross beams, the bottom piece of foam board was squished down on top. Then we added the top piece of foam and held down each piece with a heavy cinder block. This provides an extra seal that expands into every little space in the trailer for maximum insulation. After each piece of subfloor was measured, cut, and drilled, a sealant (Liquid Nails) was put on the metal beams for an extra hold. Once the Liquid Nails is applied, you have to lay the board down and start screwing it to the trailer quickly before everything dries. We used wood-to-metal screws, and again, I was pretty much too weak to help on this part. Slowly but surely each piece fell into place like a giant, heavy puzzle.

One thing to remember about insulation is that it’s incredibly important that it stays dry. If it were to get wet, the chance of mold/mildew increases significantly, and it makes the whole house sad and smelly…and probably unhealthy. While working with the foam boards and subfloor we were constantly checking the weather to make sure no storms were going to pop up. Missouri isn’t really a place you can count on for consistent weather, and Sunday night the rains rolled in. Eric and David had to cover the exposed styrofoam with a large tarp. (Because the AdvanTech flooring is incredibly more water resistant than plywood subflooring, we weren’t as worried about it getting wet.) But by Monday morning the rains had stopped and it was time to start working again. The tarp worked and, whew, our insulation stayed dry, so no mildew for us! After working until 12:30 am on Sunday night, Eric and David worked most of the day Monday and finally finished up around 9pm that night.


Tongue & Groove Subfloor

Tongue & Groove Subfloor

Measuring Everything


Spray Foam Seal

Spray Foam Seal

Hole for Metal Rod

Working late and REALLY thrilled about it

Working late and REALLY thrilled about it

Securing the Subfloor

Working the next morning securing the subfloor.

Really helping the guys out...

Really helping the guys out…

Drilling down the final pieces of subfloor

Drilling down the final pieces of subfloor

We have a floor!

We have a floor!

I am so impressed by Eric, David, and Chris. They worked so hard in crazy heat, but they got the floor on our trailer! Part of me wants to just use it as a parade-disco-dance-float, but I guess we should keep going and actually get a house on there. I can hardly believe it, but our next step is framing!


  • Reply Lindsay June 12, 2015 at 2:32 PM

    I am super impressed!!! You guys could get a job working as a Display Artist at Anthro or Uban no problem with these skillz.

  • Reply Brandi June 14, 2015 at 5:13 AM

    Wow!! I’m so excited to keep following your story!! You all are doing amazing work!! 🙂

  • Reply Julia Nabors June 22, 2015 at 2:12 PM

    I’m so impressed by your knowledge of subfloors. The second to last sentence is my favorite- PARTAYYYY!!! Also, this is so fun!!!

  • Reply Joel Wilsford September 16, 2015 at 3:45 PM

    You will need to build the “parade-dance floor- float” next!

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