Ice & Water Shield for our Subfloor

After the mad dash to get everything ready for the roof measurements and underlay, we've been able to set our sights a bit lower down and now that the side punctures are complete, we can start to work on weatherproofing the exterior walls. The first step in that process has been to lay down a strip of double-wide protecto-wrap (otherwise known as off-brand Grace Ice & Water Shield) along the base of the tiny house. This covers the trailer fascia, the subfloor, and all the joins at the base of the SIPs; and while it may look like a simple job, I spent an entire half day with a rubber hammer and a roller, working the rubberized adhesive into the irregular surface of our Tiny House, making sure that the two really married together. By lunch time, my wrists and hands were aching- but I managed to talk Sam into giving me a hand massage over lunch, so that was okay. :)

Subfloor Part 3: Subfloor Sheathing

Once the fascia was attached to the trailer, the next step has been to put our subfloor sheathing on top of the trailer. We have a 3/4" CDX T&G OSB subfloor sheating.  

One would think that the most challenging part of this process would be cutting the OSB to fit around the wheel wells, or perhaps getting the runs to be perfectly straight and square along the length of the trailer. For us, however, the most difficult part of the process was attaching the subfloor sheating to the trailer. We ended up snapping at least 4 drill bits- you can totally forget about the 'self-tapping' feature of our OSB-to-Sheet Metal screws. But we did manage to get it on in the end.

The next step will be to measure and mark out where the sill plate will go and then we'll get our SIPs up!

Subfloor Part 2: Trailer Fascia

Feeling mostly recovered, we went back to work today. Having installed the subfloor insulation, the next step in the process was to attach fascia boards to the sides of the trailer. This fascia will consist of a 2x4 screwed directly to the metal of the trailer, and an additional 1" thick board screwed into the 2x4. Together, these two boards will bulk out the trailer by 2 1/2" on each side, to extend our building space. 

The first challenge we faced was actually getting the screws we needed to attach the 2x4s to the trailer. We had purchased special self-tapping plywood-to-sheet metal screws for this purpose, but quickly found out that the "self-tapping" feature didn't work so well, We ended up clamping the boards to the trailer, I went around the edge drilling through the 2x4s and into the metal with a titanium drill bit, while Sam followed closely behind, securing the board with screws. Even with the pre-drilled holes, it took a lot of muscle to get the screws into the metal. I'm glad it was Sam who had to do it all and not me. 

Once we had figured out how to get the boards attached to the trailer, the next challenge was to fit the boards around the wheel wells and the all-threaded rods which were welded to the outside of the trailer. (These will later be used to bolt our sill plate to the trailer, but for now they're just an annoying thing to work around). 

Several cuts with the miter saw on a piece of scrap lumber helped us determine that a 24-degree angle was needed to marry the fascia board to the wheel well. After that, we marked the position of the threaded rod on the board, Sam gave it a few cuts with a skill-saw, and chiseled out the rest.

 

We needed to finagle some of these channels to be deeper or wider than we had originally marked, but mostly it was a straight forward process and after Sam and chiseled out the furrow, they sat nicely against the trailer. 

We're pretty much done with this step- although we still have the porch to handle, I expect we can get that done tomorrow morning. Once it's handled, we'll be moving on to the subfloor sheathing!