This is the story of building a HiLine house in rural King County, Washington. We started with an existing mobile home with an existing, functioning septic system. The mobile home moved 100' and the new home was built on the same pad as the former mobile home. The site had no zoning, shoreline, or critical area (wetlands, steep slopes, or endangered species) problems.
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Step 1: Permitting and Septic - 1
The first step is to spend $14,000 on permit fees and costs. Included in this amount is the study and fees for a new septic system. Although the existing system is fully functional and we are not adding any bedrooms, it does not meet existing codes. The new system is a pressurized sand filter system. First, one puts in a 1,500 gallon, 12,000 pound reinforced concrete septic tank with an outlet. Next, puts in an identical 1,500 gallon, 12,000 pound reinforced concrete surge tank with a pump adjacent to the first tank. The surge tank is needed in case one has a huge party that generates more than 750 gallons of waste water in one day. That step costs an additional $10,000. Then you cover that all up. When done it looks like this
Step 2: Septic - 2
The pump from the surge tank pumps the waster water into the actual sand filter. To build a sand filter, dig a hole 5' deep and 22' square, put in liner, some pipes, and another pump. Then fill it in with special sand and a layer of dirt to bury it. This costs an additional $10,000 and looks like this.
Step 3: Septic - 3
The sand filter pumps the waster water to the distribution field. To build such a field, one digs 5 trenches 50' long and 2' deep. Then put in some pipes and special gravel wrapped in filter fabric and covers it all up again. This step costs an additional $10,000. When done it looks like this.
Step 4: Septic - 4
The pumps along with their floats have to be wired up and coordinated with each step. That will cost $2,000 - part of which is finally above ground! We have now spent $46,000 and haven't even begun to dig out the foundation.
Step 5: Finally - the House Starts
Several steps compressed here. HiLine starts to build the actual house and they are doing a very good job. HiLine has about 10 set plans and used the same subcontractors all of the time. Therefore the subcontractors know exactly what they are doing having built the same house several times. The lumber arrived all precut and marked where the connections were to be made. It was not so much construction as assembly. The only cuts the framers made were diagonal end pieces.
The foundation and stem walls were poured separately - the foundation man wanted to make sure that the stem walls were perfectly level for the framers and therefore did the foundation separately. There is no basement - only a crawl space. The framers then came, put down a vapor barrier over the ground inside the foundation and hung the floor trusses.
After an inspection by the County for foundation connections, framers returned and put in the flooring, inside and outside walls. The roof trusses were made offsite and delivered and placed on the rim joists. Along with the truss delivery was the engineered design with the engineers stamp. Each trusses had a certification stapled to it certifying that it was built in accordance with the design. The framers returned, flipped the roof trusses over and installed them. They then sheathed the walls and roof. The subfloor and sheathing were oriented strand board. Each sheet was numbered and referenced in the plans. Finally, the framers wrapped the house with a vapor and wind barrier.
Step 6: Roofing and Windows
The shingles were delivered with a truck that had its own hydraulic boom assembly. Thus they were able to place the bales of shingles on the ridge roll. The next day the roofers arrived and installed the shingles and skylights in 6 hours. Their air guns were going so fast it sounded like automatic gunfire! All of the subcontractors so far have been 2 man crews consisting of the principal and 1 helper. They say that Hiline accounts for about 1/3 to 1/2 of their work. They have all been experienced and have worked with HiLine for several years.
HiLine purchased the vinyl windows from Milgard "with installation". So the installer who put them in was a subcontractor to Milgard. So any problems with them will be Milgard's problem and they won't be able to say it was the installer. I do not expect any problems as the installer was experienced and the installed windows were caulked and flashed.
Step 7: Plumbing
The plumbing is in. They used PEX piping. I was unaware of PEX until about 6 months ago. The joints are similar to hydraulic connections. So the greater the pressure - the tighter the connection. No more solder or glue! For the amateur
it is great. And apparently for the professional the greater cost of the connections is more than offset by less labor. Again, the plumbers were a 2 man crew who had done this same house several times. They also ran the gas line in to a future propane fireplace in the house. I counted 139 holes they had to drill through the studs!
Step 8: Electrical
The electrical rough-in is in! Which eventually means heat! The 2 electricians ran 220 v, 110 v in 12 wire and 14 wire, GFI circuits, cable, doorbell, grounding for the gas, fixtures, and a service box! If it is wire - they did it. And apparently well - at least the inspector said they did a good job and signed off on their work. The electricians estimated 2,500' of wire in the house. I counted 302 holes in studs and wall plates for the wires! Thank goodness for right angles drills! I have come to the conclusion that after all the holes in the studs, the lumber no longer holds the house together - it is the wires and pipes! They put in protector plates on the studs wherever wires pass through the studs. I believe that the electricians used their hammers more than an carpenters did.
Step 9: HVAC
For heating and cooling we will have a conventional heat pump. The air handler is placed in the attic space instead of the garage. Such a placement allows the main distribution line to be in the rafters instead of the crawl space. That saves on labor (and some on material). No one wants to work in the crawl space! That means that the air vents are in the ceiling rather than the floor. I was concerned that such a placement would not be conducive to good air circulation during heating season (but good during our brief cooling season). However, other contractors have assured me that it would not be a problem because the air tightness of present houses. Nowadays the air circulation is driven by fans rather than convection. The electrician had to come back to wire and hook up the air handler.
Step 10: Siding!!
It is amazing how much siding makes a house look finished! It is vinyl siding because we don't ever want to paint it. The workers came on Sunday to start the job and came back the following Sunday to finish it. They seem to have done an excellent job. The trim on the corners and bottom goes on first. Those pieces have a broad flange which the "boards" fit into. Getting the trim on just right seemed to be half of the job. Once on, the rest went quickly. Sort of like masking when painting. When finished, they explained how to fix small dents, how to pressure wash it with the grain to keep water out from behind the pieces, and not to build any fire close to the walls!