The final footings

Here's a nice view of the finished footings. Surprisingly (to me), they took one relatively damp afternoon to dry. The water just rises to the top and either evaporates or runs off. The three footings inside the house are for the chimney (right) and interior posts (two footings at left). These were poured about a foot too far to the left. I caught it though with my trusty measuring tape. The foundation contractor just extended them one foot to the right. Good save, Roger.

Concrete, if used correctly, is a fine thing. Sure, it has a nasty carbon footprint, but note how the footing keeps the water from that little spring pooling in the crevice at bottom right. This is good, because it is not pooling inside the house. Water pooling under the house is not environmental; it leaves mold. We filled this pool with extra concrete left over after the foundation pour. The spring now drains behind the house (to the left of the photo).

Rebar

Two lines of horizontal rebar was placed in the poured footings after the pour to reinforce the concrete. Roger Laroche and his helper very quickly cut and bent the vertical rebar using a cutting and bending tool. Roger can be seen here laying the vertical rebar into the footings as I look on anxiously, wondering how much this is all going to cost (it should actually be close to the estimate; Roger said that the site was actually easy to work; I believe him; it took him a morning of work to do all this).

Three steps were built into the footing. The largest is seen here is along the back wall and is about 10 inches in height. Roger built these with conventional forms in mind. Styrofoam forms for foundation walls would have required more precise (and hence labor intensive) step measurements.

The rebar (which will anchor the walls to the footing) is offset slightly to the outside perimeter of the footings to allow for interior pilasters in the foundation wall. Two vertical rebars are placed where the post-supporting pilasters will be poured into the concrete wall.

The the far right of the image also shoes the trench in the rock that runs behind the house . It should divert water from the spring away from the house.

Drainage on north side of house

Because the surface bedrock we are on is an impermeable chlorite schist, any downpour or spring thaw will run off on top the rock. This means that we should take advantages of natural cleavages and ruts in the bedrock to divert any water away form the foundation footings.

The north side of the house is naturally drained by a crevice that Normand managed to excavate with the bulldozer. I'm glad he did because it allowed us to position the house adjacent to the crevice as opposed to over it! It actually does run under the northeast corner of the house seen in the back of the image. Fortunately, it is not as deep as pictured in the foreground.

To make sure the part of the crevice under the house drains, we placed a drainage tube under the footing (pictured here at bottom). The water line from the well will run through the top tube. The backfill will will be about 3-4 feet here and be covered by a board of Styrofoam SM. That should keep the water from freezing in the wintertime. Hopefully, we'll manage to keep water from entering under the house at all by draining the water into that rut that runs behing the house.

Drainage for spring

A small spring in the driveway uphill from the house drains towards the house. It pools in the middle of the house (seen here). At bottom left is the little ditch in the rock that carries the water to the house. The footing forms block the flow in the picture. The square footings int eh middle of the house are for the chimney and the two interior posts.

Here I am filling the ditch with excess concrete dumped from the hold of the pump truck. The idea is to divert the flow to the left behind the house where another ditch will carry it away from the foundation. We will fill this ditch with weeping tile and crushed stone to make sure it drains this way.

It's not as tough as it looks. The concrete mixed with the water and proved to be quite easy to shovel over. Mind you, I wouldn't want to bend over like this all day. This should divert runoff to behind the house for now. I couldn't fill all the way to the footing because the contractor will need to remove his forms. We will fill in that hole when we pour the foundation walls (will be about 3 to 4 feet high).

Pouring the footings

The original estimates for the foundation all included an extra item for a concrete pump that would make work ont he site easier. We thought it would have to be a hell of a pump to justify the cost. Little did I know it was a whole truck. Here the cement truck pours the concrete into the pump truck, which delivers the concrete with this huge crane. The concrete workers pour the concrete.

The concrete is 25 MPa concrete (that's megaPascals) for both the footings and foundation walls. According to my calculations, that means it can withstand 100 000 kg loaded onto the 8''x8'' hemlock posts that the foundation will hold. Obviously, the concrete is not the weakest link in the house. It was dry and ready to walk on in about 6 hours. We had ideal conditions for drying: no rain, a little sun in the afternoon, temperatures around 15 C and a light breeze.

Here's a closeup of the contractors. The concrete is from Beton Cowansville. The concrete contractor stands at left as Laroche pours and his journeyman helper evens the pour.

We thought that the footprint of the house was awfully small. I double checked a few measurements and they all checked out. The walls will actually stand slightly offset to the outside, so that there is actually a foot more interior room than there appears to be with just the footings.

Forms for footings

We went with 2 foot footings directly on the rock. I'm glad we did. A 2-foot barrier bonded to the rock should divert away any runoff moving along the top ot the rock.
The plans for the foundation are outlined here.

The foundation contractor (Laroche et fils) showed up with a flat bed and crane that deposited and a nice portable tool shed on the site (see previous post). The excavation had actually left the site more even than anticipated, despite some undulating crevices and depression that caused the water to pool. All in all, the footing ended up having only three steps, and the final height varies by no more than a foot.

This image shows where the footing is at its thickest at the corner of the "shed" extension. The footing actually dips into a crevice in the rock that will act as a natural drain for the north side of the house.