New Water Tank (Page 3 / 3) -- July - August 2004
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Before building the walls, we needed to get the tank up on it's platform, and reconnect it to the house. We also had it filled for the first time. The image on the left shows the tank, completely full of 6 tons of water, and in it's final location.
I don't have any images showing the construction of the walls and roof, but the walls were 2 x 6 construction, 16 inches on center, and the roof is 2 x 8, also 16 inches on center. The span will be able to support more than 50 inches of snow. The back door was a pre-hung door, cut short to fit the small opening, and I built the door for the water man using a double frame of 2 x 4's with insulation in the middle.
I wired a new 20 amp circuit to the sub-panel in the garage, and installed a GFCI receptacle as the first outlet off the panel. There are two other receptacles, including an outdoor receptacle just outside the back door to the shed. I installed a light in the ceiling that's controlled by two two-way switches just inside each door to the shed.
The upper image on the right shows the shed from down in the dogyard. That's Buddy on a doghouse, and Deuce is watching me from the deck. The walls sit on the platform I built and the ends are nailed into the framing of the house. The roof joists are hung from a ledger board lag-bolted into the framing of the garage wall. You can see a small ledger board at the left edge of the shed roof that intersects with the corner of the house. Inside the shed, the ledger board is also braced with a pair of 2 x 4's that rest on the floor of the building. At the moment, I haven't build a set of stairs to access the back of the shed (where there's a couple feet of storage behind the tank), but the old doghouse works for now.
On the left you can see a view from below, also inside the dogyard. Here you can see the pilings in the ground, and the stack of three 2 x 12's that hold up the massive floor that supports the tank.
From inside to out, the walls are sealed with a vapor barrier, filled with fiberglass insulation, covered with 1/2" plywood and then wrapped with 30 pound tar paper. Because I don't plan on putting any heating directly into the shed, I didn't hang drywall inside the shed, but if a heater is necessary, I'll need to do that. As you can see, I ran out of siding, but next summer I'll get more and finish it. Lathe is nailed up over the tar paper to form an airspace behind the 8" bevel siding.
The roof is the same basic design except I used 5/8" plywood and there's no lathe between the tar paper and the metal roofing. The roofing is held on with screws that drive down into the plywood and have rubber washers that keep the roof watertight.
From the other side, you can see the siding that matches the rest of the house. I needed to hang the siding in this area because we had to move the oil tank. It's in a better location now, both because it's out of the way, and because it doesn't obstruct the exhaust vent to the monitor that's on the other side of the wall in the garage. It's the little sliver circle you can see in the wall to the right and below the oil tank. If there isn't enough space around the vent pipe, the monitor will pull in exhaust gas instead of cleaner air, and the monitor will foul itself and stall.
After five years in it's old location, I also decided that the tank needed better footings. When I originally installed the tank I just buried a small slab of a 2 x 6 under each foot of the tank. This time I got a set of concrete footings with adjustable clips designed to hold a 4 x 4 post. It turns out that the iron feet on the tank stand fit perfectly into these clips, so I buried the footings and set the tank on them. Our fuel company (Polar Fuel) kindly emptied our tank for the weekend so we could move it.
The last image shows the door that the water man uses to fill the tank. You can see the access hatch for our tank just inside the doorway, and also the light that he can use to see when the tank is getting full. When discussing the project with the guy who delivers our water (Arctic Water Works), he said that the two most common options are a doorway like I built, or a fill and vent pipe that extend out of the building. The disadvantage of the vent and fill pipes is that he can't tell when the tank is full until water starts coming out of the vent pipe. Because the shut-off is at the truck, water will be pouring onto the ground until he can get back to the truck to shut it off. With a doorway and a good view of the tank, he can watch the level and walk back to the truck in plenty of time so he doesn't spill any water.
So, now that it's all built and insulated, there are still two major tests to pass before I conclude this design was a good one. First, we need to make it through winter without the tank freezing. I don't think there is much danger of the water in the tank freezing because water has such a high specific heat. But the 3/4" line that runs from the tank into the garage is a narrow point that could freeze if the shed gets very cold. My plan is to increase the size of the opening between the shed and the garage in order to allow heated air from the garage to keep the supply line thawed all winter. If this doesn't keep things warm enough, the next step will be to add a small fan on a thermostat that blows warm air into the shed when the temperature gets too cold.
The second major test is whether the pilings move next spring during breakup. The soils in our area are composed almost entirely of silt down to about eight feet. And I didn't wrap the pilings with plastic before burying them, so it's possible that there could be some frost heaving of the pilings if the footings don't keep them anchored. Neither of these should be an issue because the footings are large enough to support the weight of the building and water, and are more than a foot and a half below the bottom of the frost layer. But building in Alaska isn't an exact science, so I'll be holding my breath in April and May, watching the level of the rails that support the shed.
Most people building homes in Alaska bury their tanks. Maybe plastic tanks last longer than the metal one that the builder installed when this house was built (1986), but I think having a tank visible and easy to access is a better idea. Time will tell whether this was a wise choice. The other major advantage of installing a tank above ground is that it's at least half as expensive as contracting someone to bury a tank.
[ Last updated Saturday October 2, 2004 ]