Excavating Wet Soil

We continued to dig down, though water was still slowing things down. Our lot included a lot of clay, which holds onto water. And excavating wet soil is a problem. But we were making progress:

But each deeper cut revealed more water:

The orange hash mark on this back wall marked the level of the garage slab – basically the lowest flat section of the house:

From there, we needed to get four feet down to get our footings low enough before the frost line. Then we needed to get another 4-5 feet down in order to get out enough of the clay (“overdig”) to replace it with architectural fill (basically gravel). So we needed 8-9 more feet of depth below the hash mark. The flat section of the dig in the photos, which was mostly dry, was 3 feet down. And the water is at about 5 feet down. That’s…. not enough feet.

The deeper test hole continued to fill up with water. Shaun continued to pencil out options. A couple of weeks after we started excavating things in earnest, he gave us the following options.

Option 1: Scrape and Dry

We could keep doing what we were doing: scrape and let things dry before digging deeper. Given the water and the additional over-dig we would need to do in order to ensure the footings stayed dry enough, Shaun estimated this would add $45,000 to our excavation costs, up from our original excavation budget of $45,000. I noted, grimly, that you could get an awfully well-loaded Toyota Tacoma for the same money. Unfortunately, Shaun told me we couldn’t just dig a hole and drop a Tacoma in it and build a house on it. But we still called it The One-Tacoma Option.

It would cost additional money, but it would also be slow, since we needed things to dry incrementally. 

Option 2: Piers

Shaun also penciled out what it would take to scrap the idea of standard concrete footings to hold the house up and replace them with piers. Footings are essentially pieces of concrete that sit on soil to hold the house up. Piers are cement columns that ideally rest on bedrock. Since they rest on bedrock, it doesn’t matter if the soil is crappy or wet. That was the good news. It would also be relatively quick, since soil moisture wouldn’t matter much.

The bad news was that the structural engineers estimated we would need 30-40 piers, and they were likely to cost an additional $60,000-$90,000 on top of our $45,000 excavation budget. Another two or three Tacomas.

We leaned toward the One-Tacoma option, and so did Shaun. We asked him to take a look at what we could do to speed things up some, and set a call with him.

Evaluating our Options

Our call went well, though it didn’t include a lot in the way of news. Piers seemed too expensive and didn’t give us much, aside from a slight timeline boost. But that didn’t seem worth another $40,000.

In order to speed up drying the building pad, we decided to dig two trenches to full-depth, one on each side of the pad. The hope was that these would draw water from the pad into the trenches, where it could be pumped out. Hopefully that would speed the process of drying the dirt in the pad.

We talked about whether we could do the excavation “wet,” — excavating wet soil without letting it dry. Though it was possible, it would also be expensive. The excavators would likely need to scrape or spray out buckets and trucks, since the wet clay would try to stick to them. It would also be heavier and expansive, requiring more trucks to haul it away and more space to try and hide it on-site. So, like the piers, it could speed up the process but it would be pretty expensive.

We decided to try the trenching to see how that did. Shaun thought we could keep our move-in timeline even with the delays, and hoped to be ready for concrete about three weeks out – basically sometime in the second half of July.

Book Reviews

A little more non-required reading:

Cabins & Camps: A great book if you think that “cabin” means that everything should be built out of logs. The walls, the roof, the couch, the end tables – logs logs logs. 

Snow Country: Mountain Homes and Rustic Retreats: Pretty pictures of mountain homes, trending largely towards the chalet crowd. Ski Style: Alpine Interiors, Architecture & Living Style has some more of the same.

The Family Cabin: Inspiration for Camps, Cottages, and Cabins: I have a soft spot for cabins – my parents had a tiny lake cabin when I was growing up. This is a solid collection of cabins with notes on design ideas. They lean towards midwestern and Adirondack lake cabins, but there are a lot of good little ideas here.