Finally some progress this week! Matt, the builder, came by to shoot elevations. Up to this point there were 2 key questions to confirm: 1) what is the actual grade change in the greenhouse location? and 2) will the 60′ greenhouse fit within the space between existing structures?

Confirming the grade change

The plans for how and where on the land to make the cut to level for the greenhouse had been based on our estimate of a 4′ change across the 60 feet from greenhouse end-to-end. Turns out to be a pretty accurate guess as the actual change is 4’8″. This means we won’t need to adjust the plans and can go ahead with only one 4′ retaining wall between the carport level and the courtyard/greenhouse level (see green oval on site plan, below).

Adam, the excavation contractor, came by later in the week to look at the site and all the project details to prepare his bid. Fortunately he’s done work on the properties on both sides of mine so he’s familiar with the type of soils, and where he’s run into solid rock ledges, on the property around mine. Adam’s going to come by next week to dig a test hole or two to check for soil conditions. The predominant soil type in this area is glacial till with some top soil.

My first building experience was raw land in the Cascade mountains where we ran into a solid granite ledge across about one-third of the ‘basement’ area. We first tried breaking it out with a 90-lb jack hammer; that didn’t make even a dent. Then we tried an hydraulic rock-splitter; again hardly even a dent. Finally, we racked up 40 hours on an excavator with an hydraulic rock hammer. Fortunately here in the islands, even the ‘solid’ rock is generally weak and can be broken by a backhoe. Adam’s equipment should be able to handle any condition on my property.

Confirming the greenhouse size and location

Locating the greenhouse is where it gets tricky because of the multiple existing structures that leave only one area where the greenhouse can go. Unfortunately the site plan as drawn has the septic drain field in the wrong location and has the greenhouse (yellow rectangle on the plan, above) in a location it can not go because it does not fit within the setback and the actual location of the septic drain field.

This property was formed by dissolving the interior boundary lines of what were formerly 2.5 parcels. The red dot on the site plan, above, is where the ‘upper’ parcel’s lower line meets the ‘lower’ parcel’s upper line. Because the septic drain field is actually closer to the lower edge of the upper parcel, the greenhouse can only fit on the ‘lower’ parcel (i.e. to the ‘left’ of the red dot).

The ‘red dot’ on the plan above is the critical property corner for siting the greenhouse as it is the farthest to the ‘right’ that the greenhouse will fit. The purple box indicates the available footprint for siting a 60′ greenhouse. As it encroaches on one of the existing sheds (inside the red rectangle), I have the unfortunate choice of either reducing the greenhouse length or moving (or demolishing) the shed.

For cost reasons, the greenhouse will not be custom built on site; it will be a pre-manufactured and erected on site Conley’s Gable 7500. This model offers lengths in 10′ increments. Therefore, if I choose to reduce the greenhouse length, then the next option is 50′. Since the house is 30′ long, reducing the greenhouse to only 50′ will really effect the usable indoor growing space and the sense of space ‘under glass’ so this option is highly disfavored.

Alternately, I could move the existing ‘workshop’ shed approximately 15′ to be parallel to the ‘office’ shed. The workshop shed was a bathroom cabin for the former property owners. By the time I took over, however, there was substantial water damage from a leaking roof and broken water pipes that all the utilities have been disconnected and the entire interior has been gutted back to the studs. The entire structure is on 4×4 posts. Matt, the builder, and Adam, the excavation contractor, estimate the building can be moved with their existing equipment and without too much effort. So that is what we’ll do to be able to keep the 60′ long greenhouse as planned.

Next up is digging a test hole or two to determine soil conditions in the excavation area and to begin trenching for the new utilities.

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