As you may have realized, my tiny house is currently under construction in my garage. My very, very small garage. Thus, there is no way for me to build the entire structure onto the trailer while indoors. I could move my project out into the driveway and continue my build there, however, as this is a slow-moving project I would end up exposing the framing material to inclement weather before I would be able to complete the framework and exterior sheathing. So rather than try to rush the project by building the walls outside directly onto the trailer (undoubtedly alienating my neighbors in the process) I have decided to build the walls in the garage, and then take them out one by one to the driveway when it is time to raise the house.
Now, for this endeavor, I had two requirements. First, the walls needed to be complete with sheathing and vapor barrier installed so that I could raise and seal off the structure in a single day when it comes time to move the project outside. Second, the walls needed to be dis-connectable, so that I could put them up one at a time (wood framing is heavy!).
To begin, I started with the framing of the two trailer ends, as the difference in height would determine the slope of the roof and angles for the top of the side walls. I built my framing using 2″x4″ douglas fir, and connected pieces using 3” construction screws. The wall at the front of the trailer will have the bed frame resting against it, and I thought a large window would be perfect for the area. I measured a 36”x48” rough opening for the window, which will rest slightly above the mattress when the bed is installed in the final structure. The wall at the end of the trailer will have a 24”x6.5’ out-swinging door. The front wall has a height of 7 feet, and the back height of 8 feet, therefore, the roofline will rise 1 foot over the 12-foot length of the trailer (1/12 roof pitch).
Once the roof’s slope was determined, I was able to start construction of the side walls. As one wall would have a desk and the other the kitchen worktop, I decided two opposing windows would bring the perfect amount of light into the room, as well as give me a great view of the surrounding area wherever I end up parking my tiny house. The window above the desk area will be huge, with a rough opening of 36”x60”, and sits at the same level as the front window. The kitchen window will be smaller, with a rough opening of 36”x24”. The sidewall framing is built out of 2”x4” douglas fir, with 24” centers and many stabilizing joints in between that will also function as fire blocks. The roofline was cut with an approximated 4.76° angle to provide the 1/12 pitch previously calculated.
The next step of the process was to sheath the walls using 3/8” thick OSB. This gave the structure much-needed stability and will act as the general protective barrier for the house. The OSB boards came in 4’x8’, with a total of 10 boards needed for the wall sheathing. They were secured to the framing using 1-1/2” construction screws, and the rough openings for the door, windows, wheel wells, and roof pitch were cut out using a skill saw. Next, the walls were wrapped in Tyvek House Wrap from bottom to top, with seams sealed using Tyvek House Tape. The rough openings were cut out, and the openings flashed using Fortiflash House wrap.
As of this point, the walls were individual constructs and needed to be temporarily connected to make sure my measurements were correct. Thus, the four walls were interconnected using 1/2”x8” lag bolts, two in each corner of the house. These lag bolts will also allow for easy connections when it is time to finally raise the structure, after which many supportive bolts will be added.
Once the structure was roughly put together, I was able to do the prep work for the roof. Since its such a small structure, I didn’t see the need for creating an overhang. Instead, I cut five 2”x4” joists that would run the span between the two side walls. I installed industrial aluminum joist hangers at every 24” center along the side walls. When it is time for the final raising, I will secure these joists using lag bolts drilled into each joist end from the exterior of the house. OSB will be laid on top, flashed, and the roofing laid down.
The door was a particularly exciting project, as it was my first time trying my hand at it. It needed to be short in width since any area it encompasses takes away from the bath area at the end of the trailer. I settled on 24” wide and 6.5’ tall. The door was made using two 2”x6” boards on the sides, with a mixture of 2”x4” and 2”x6” planks in the middle. The pieces on the top and bottom were secured using lag bolts hidden on the interior side, while all other pieces were secured using gorilla wood glue. The project was clamped and left to set overnight, and it was incredibly sturdy the next day. I sanded the project down, first with 80-grain then 230-grain sandpaper. After which I applied two coats of exterior wood sealant. Overall I like how the look turned out. However, I’m still not too fond of the seams in between the boards, and I plan to use a router to create a dipped edge along all seams and fill with black epoxy. I’ll let you know how it turns out!
I also needed to create a door frame which would sit in the rough opening of the wall framing. I used 1”x4” boards to create the frame and 1”x2” boards to create the jam. I placed the jam so that the door will swing exteriorly, as I will not have much room in the interior space. After sanding and sealing, the frame was secured using 1-1/2” black screws that went into the wall framing for a secure hold. I also added a compressible vinyl sealing gasket along the exterior edge so that when the door closes it will provide an airtight gap. The final pieces of this project will be to add the exterior swinging security hinges, doorknob, and lock.
Finally, I started working on creating a front utility box, which will house my gas tank, water heater, and toolset. I used 2”x4” boards for the frame and 3/8” OSB sheathing to create this project, most of which was leftover material from the walls. The box was designed with angled edges that run parallel to the front bars of the trailer so that whenever turning the vehicle pulling the trailer I run a much lower risk of hitting the box with the taillights. I still need to wrap the box with house wrap, build its door and add in shelving, but the bones are assembled and ready to go!
With the completion of the walls, my budget for the school year has reached its limit. As of now, I have spent $4,190 on the house, and I estimate about $4,000 additional to finish the entire tiny house! About $950 of this total was spent on materials for the walls, and I have attached my budget and materials list below. I will begin work on raising the structure, installing windows, and exterior materials at the beginning of August! Stay tuned 🙂