This past week has been really fun! We are making lots of progress and now have wall and ceiling insulation, all electrical wiring laid, and windows installed. It's so nice to have all the natural light and it makes it feel much bigger inside!
Let's talk about insulation first. We struggled with the decision of what type of insulation to use because they all have their pros and cons. Here's the details on the types we considered:
1. Fiberglass, rock wool, or other bat insulation: This stuff is really easy to install and it's the cheapest option. It would have been fine for the wall insulation, but not for the ceiling. The ceiling needs something with a higher R-value since the sun and snow both affect the roof directly. There is no way to form a complete vapor barrier around the bats, so the roof would need to be vented, so that condensation can't get trapped in the air pockets.
2. Rigid foam insulation: Rigid foam sheets are better than bat insulation, since they provide a higher R-value with less thickness. These would have worked alright for the ceiling. We could have layered a couple sheets to get a high enough R-value and used canned spray foam insulation to fill in any gaps. The issue we had here was that we still would probably need to vent our roof, because filling air gaps completely is a challenge. Some of our roof is framed with 2x4s (instead of 2x6s), providing little space to install multiple sheets of rigid foam, meaning the R-value in those areas would have to be less.
3. Closed cell spray foam insulation: This is ultimately what we ended up choosing. It is the best all around product because it forms a complete air and vapor barrier, meaning the roof does not need to be vented. Spray foam also provides a higher R-value with only a couple of inches of foam. The only downside is the cost. It probably cost us more than double what other insulation would have, but it made sense for us with our tight construction schedule. We were able to have our entire house (wall and ceiling) insulated in under 5 hours. It also made sense for us because we are going to be traveling with our house through all different types of climates. This insulation gives us the absolute best preparation for whatever weather we may see on the road.
The most expensive part of the spray foam is simply getting the equipment to the jobsite. The installers showed up in a large truck that houses the equipment and just fed a hose out of the back of the truck and into our house. Honestly, I think we could have saved some money by bringing our house to their warehouse (it is on wheels, after all), but we were in the middle of other projects and didn't want to risk the roof flying off as we drove down the road because it wasn't entirely complete. The total cost was around $1500, which is their absolute minimum order. It's just not worth it for them to drive the truck out for anything less.
Prior to getting the insulation installed, we ran all of the electrical circuits to our various switches, light housings, and outlets. This was something we needed to do early because the insulation becomes very rigid once it is set. We have 15 light fixtures and 15 outlets. This might seem like a lot, but we can't have any table lamps or anything that will fly around while we are on the move. Everything has to be a permanent fixture. We wanted to give ourselves enough options to have the right lighting for any occasion. We will talk more about our complete electrical system in another post!
Finally, we installed all our windows. We have 9 windows, including 2 in the sleeping loft and 1 in the storage loft. We went with vinyl windows as they're the cheapest and the lightest while still being very resistant to weather and rot-free. They also create a better separation from the outside than aluminum framed windows which don't provide any good thermal break (meaning the metal frame creates a good path for heat transfer).
It's so fun to see the house start to come together and really envision where everything will go!