Cabin part 2: Foundation (finally!)

The foundation was the biggest holdup in the entire process. There are only three masons working in Cook County (where our lot is), and they were all so busy this summer that most of them didn't even return phone calls. We were also held up waiting for our building permit, and lost one contractor because we couldn't commit to his start date since we did not yet have our building permit. We finally found John Elias Masonry out of Cloquet, MN (near Duluth; about 165 miles away), who had a three-day window at the beginning of September. We jumped on it. The masonry crew was there for three days, and stayed at one of the local resorts. (Ca-ching!)

Day One: We had previously cleared the site down to bedrock (seen at left, still wet after power-washing), and in this situation masons build stepped, poured-concrete footings that they pin to the rock by drilling holes in the bedrock and inserting metal rebar, which becomes embedded in the concrete when it is poured. They build a stepped series of wooden forms to contain the concrete; the poured cement footing is about 24 inches wide.















If you've never seen a concrete pumper truck, all I can say is, wow. It is a huge machine with folding arms (seen in the photo at right) and a long, snout-like tube through which the concrete is pumped. In the photo above right, you can see Dan (in the gray hoodie) guiding the snout to fill the forms with concrete; Andy (in the gray cutoff shirt) is to the far right in the photo, smoothing freshly pumped concrete. The snout apparently weighs about 100 pounds and it is quite a job to control the beast.

The pumper is controlled by a guy with a remote-control box strapped around his waist; he can move the arms to lower the snout, swing it side to side, and control the flow of concrete. The pumper truck here came from Duluth, and stayed for two days to work on our job (ca-ching!). It was run by a wildman named Chris (also known as Bo), who clearly enjoyed his work as seen in the photo below right.

We also need two footings for deck posts. The thing that looks like a Gemini landing capsule in the photo at left is the base of the Sonotube post footing; it's bell-shaped so it has a broad base, and inside the bell they've embedded a number of pieces of rebar. These were also filled on the first day.

After the forms and Gemini capsules were filled, Chris folded up the arms and cleaned out the pumper. Note the name on the arm of the pumper, seen in the photo below right ... kind of a funny name for such a huge piece of equipment! (You may have to click on the photo to see the enlarged version, in order to read the name.)

We were plagued with rain throughout the footing-building process; both the workers and we were like drowned rats. About 30 minutes after the foundation was poured, the skies opened and we were lashed with nearly 2 inches of rain overnight.

Day Two: In addition to the stepped footings, we needed two ICF walls (insulated concrete forms), which are made by stacking modular units with styrofoam on both sides of an open area in the middle that will be filled with concrete. As the modules are stacked, the masons position more rebar in the open area, securing them to a web of plastic spacers between the two styrofoam sides. After the concrete is poured, the final result is a concrete wall that is 8 inches thick, insulated both inside and out with styrofoam and reinforced throughout with rebar. Got it?

The first step is to cut away the wooden forms that were used when the footings were poured. Since there was a lot of rebar involved, sparks were flying during the removal of the forms. (Got gas?)

After that, the ICF forms went up very quickly, which is a good thing since Chris was scheduled to return with the pumper truck in the afternoon.

In the photos below, you can see the lower-level foundation walls as well as the full-height walls on the west and south sides (each wall was 8.5 feet above the foundation).

There were some very tense moments when it was discovered that the concrete supplied by the local mixer was too loose, and the ICF walls were in danger of collapse (which would have been a monumental disaster). Luckily it all worked out, and the walls stood even though they shook like jelly (literally) when the workers pushed on them. Scary stuff.

Next, we had to cover the walls with a waterproofing membrane and some pebble board (to deflect the pressure of the backfill) and add drain tiles. Another blog post shows these steps.