The week following the installation of the aluminum flashing, a thunderstorm rolled through in the night and it rained with a fury. The entire deck was covered in water. Since we had sealed up the seams of the flashing with tape, the water had nowhere to go. This solidified our decision from last week to not install a vapor barrier on top of the flashing. To prevent any future water-logging, Mike thought it would be a good idea to drill small holes in the flashing at each cross section of the trailer to allow any trapped water to escape.
The next major step in the tiny house build was to build the subfloor framing, attach it to the trailer, and install the floor insulation and subfloor sheathing. This process took the better part of three days, plus one additional day of ripping apart a bunch of the work we had already complete to fix an issue–back to that in a bit.
Building the subfloor framing didn’t take much time at all, but attaching it to the trailer was a time consuming process. First, we had to make a countersink hole for the bolts, then continued drilling a hole for the 7” bolts that would go through the 2x4s and the metal frame. Finally, we installed the bolts with an impact driver. There are approximately 80 attachment points on the trailer, so multiply this process by 80 and it quickly becomes a tedious task. Mike had to do most of the drilling for this since it would have taken me twice as long to do with my puny arms.
Everything is basically broken up into three sections: in front of the trailer fenders, between the fenders, and behind the fenders.
Next, we began cutting and installing the floor insulation. I’ve chosen to use Extruded Polystyrene Boards (EPB) as my insulation. Again, another tedious process because we had to cut-to-size 19 panels of insulation to fit between the floor joists. Here, Mike began to notice some contradicting information in our guidebook. In the floor insulation section, they recommended using 3 ½ inches of insulation to fill in the 3 ½ inch width of the joists (2×4 lumber actually measures 1 ½ x 3 ½ in). However, later, in the wall insulation section, they say specifically not to use the exact amount of insulation as the wall cavity because EPBs are very rigid and do not really compress. So, if the insulation extends past the cavity, you may have issues with an uneven wall. Or, in this case, an uneven floor. But, we hesitated to stray away from the guidebook and installed the recommended width of 3 ½ inches. Once we got all the insulation panels cut and in place, we used spray foam to seal up any small gaps between the lumber and the insulation. Not only does it create an air barrier, but it also acts like a glue. Once it sets, the only way to get the insulation out would be to cut it out.
The final piece to finish off the subfloor was to install the subfloor sheathing (plywood). Fortunately, we only had about five or six of these panels that we needed to cut and install. Once ready to install, we applied construction glue to the subfloor framing, placed the plywood on top of the framing and finally screwed the plywood down onto the framing. Another tedious process screwing in what seemed like a billion screws. But once that was done, it felt great to see that we had completed another phase of the tiny house project. Little did we know the following weekend of work would come to a screeching halt.
Coming up… a revisit with the subfloor and wall construction.