Utilities and Backfilling the Foundation

Before we start on the dome, we need to get some other things squared away first. We want to finish running our utilities so we can backfill. This will make the dome construction a lot easier when we can work from the outside on solid ground.

Utilities right outside the building.

We mentioned before that we’re running electrical, water, geothermal, and natural gas lines all in the same trench. We want to make sure that the gas and electrical lines are as far away from each other as possible. The main fear is that if you do dig into this trench, you really don’t want to cut the power feed and the gas line at the same time. The sparks can ignite the gas from the leak and cause a fire. Hopefully if the power cable gets cut that will alert the operator that something is there. We also ran a trace wire for the gas line near the top of the trench as well per code.

We buried the gas and water line at the bottom of the trench almost 6 feet underground while the electrical is buried in the opposite corner of the trench only 2 feet underground. The irrigation feed line is going to be ran around the greenhouse to the other side of the yard. This is the line we cut during excavation.

We’re Idiots

The excavator could only dig so close to the house due to our gas line coming in from the road. This left around 16 feet of trench that still needed to be dug so we could connect everything to the house lines. We thought we’d save some money and just dig it by hand. Let me be clear….. 16 feet of trench 5-6 feet deep by hand.

It’s a good thing the weather was crappy following this because this laid Adam and I out for over a week. We did however save a good chunk of change digging this ourselves and we were able to get the plumber and electrician in to make the connections inside the house. We were also able to connect the natural gas right at the meter so we won’t need to worry about thinning our gas pressure inside the house.

Wrapping it Up

The last thing we need to do is wrap our wood foundation in a moisture barrier. The spec specifies using thick plastic sheeting, similar to what we used under the floor, to seal the outside of the building. After combing over numerous forums and talking to an inspector friend of mine, the general consensus is that the wood foundations they found to be in the best shape used Ice and Water Shield (Bituthene).

We used 3 rolls of the stuff starting at the bottom and overlapped every layer over the previous. We were then able to start backfilling. My dad had a lot of fun moving dirt around with his tractor and did a good job getting everything packed down.

Up next we finally get to start assembling the dome.

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