Building my house on Guemes Island
Part 3: Excavation

(Part 4: Foundation)

February 18, 2022: On the same day I received a building permit from Skagit County, I got a phone call from Adam, owner of Mimnaugh Excavation on Guemes Island: he was ready to start excavating my lot next week. After a year on his work waiting list, I'd finally made it to "You're next." Yehey!

Mimnaugh Excavation

Feb. 21, 2022: The following Monday, Adam brought his Kobelco 115SRDZ excavator over and started digging a driveway on my rocky lot.

Adam Mimnaugh

Feb. 22, 2022: Having roughed out the driveway, he put the power hammer attachment on his excavator and started breaking up bedrock on the house site. By the end of the day, he'd moved on to preparing the septic drainfield.

Feb. 22, 2022: Breaking bedrock with the OKADA jackhammer attachment on the excavator (YouTube video).

Breaking bedrock with the OKODA jackhammer attachment.

Feb. 23, 2022: Adam used his excavator to remove a few more trees blocking the construction site (this photo is from the next morning when I arrived to find these logs, which had been trees the day before, now covered with a light dusting of snow. It's still winter in Washington State.)

Feb. 24, 2022: Today Adam leveled the area for the septic drainfield and dumped three big dumptrucks of sand on top. This will be the drainfield mound, a massive sand filter where effluent from the septic tanks will be dripped for final treatment.

Feb. 25, 2022: the excavation crew was busy today:
* Removal of the logs that were partially blocking the driveway.
* Removal of a big pile of stumps and brush which had been cleared from the site.
* Dumping of more sand on the septic drainfield.
* Digging the 5 ft by 30 ft septic tank hole. Adam had mentioned awhile ago that if the subsurface was hard bedrock, digging this hole could be a difficult slow (and expensive) task. Lucky for me, the subsurface rock broke up easily and he almost finished digging the hole in a few hours.
Next week: install the septic system.

Dan and Adam, the hardworking crew of Mimnaugh Excavation.

Dan and Adam

March 1, 2022: My septic tanks arrive on a truck.

March 1, 2022: Moving the second septic tank into the tank trench (YouTube video).

Adam moving septic tanks

March 2, 2022: I finished putting up 200 ft of silt fence around the building area on my lot. This involved digging 26 new post holes through the very rocky and rooty ground - I love all the rocks & roots but man-oh-man this is hard digging. The fence is a temporary measure to control potential soil runoff and erosion during construction.

Silt fence

March 4, 2022: Adam & Dan set up the septic system.

March 4, 2022: Septic system as installed: three septic tanks with "headworks" (valves and control mechanisms) connected to Oscar II drainfield drip system (drips treated effluent into sand mound for final aerobic treatment.
The complete Oscar II includes three stages of sewage treatment:
1. Tank #1: "trash tank" for anaerobic (oxygen-intolerant bacteria) treatment.
2. Tank #2: "treatment tank" for aerobic (oxygen-loving bacteria) treatment. There's an air compressor to bubble oxygen to the bottom of the tank.
(Tank #3 is the "pump tank", aka discharge vessel, which pumps treated effluent out to the drainfield for final treatment.)
3. Oscar II subsurface pressurized drip system consisting of coiled perforated plastic tubing which drips effluent into the large sand mound for final aerobic bacterial treatment.

March 4, 2022: Testing of the Oscar II septic drip system (YouTube video).

Testing of the Oscar II drip system.

March 7, 2022: Septic System Inspection. The Skagit County Health Department came out to inspect the completed septic system before the drainfield gets covered with a final layer of sand and mulch. Adam fired up the pump and the pressure gauges showed water pressure in the lines. Septic system is now approved.

 Septic System Inspection

March 8, 2022: Surveyor marks out the corners of my future house, Excavation of the building site now begins in earnest, the 25 ft by 40 ft site needs excavation to a depth of approx three ft.


March 9, 2022: Adam builds a rockery (retaining wall) for a parking apron where I'll hopefully be able to park my Spartan trailer.

Adam builds a rockery.

March 10, 2022: Water line is connected, I now have water on my site.

Water line is connected.

March 10, 2022: Water is connected, temporary service post (electricity) is erected, and lot excavation is complete. Adam estimates he removed somewhere between 200-300 yards of material (rocky soil) from my lot (his dumptruck holds 10 yards, so it was somewhere between 20 & 30 truckloads).
My house site is now ready for a concrete foundation.

Water & power connected

Next: House foundation....