A Little Work in Maine

After working a job out on the coast of Connecticut I had the pleasure of visiting my friends up in Maine. They are starting up a goats milk creamery and building themselves a little timber framed house. The house is still being designed outside of the foundation dimensions. That said, this summer they cleared the foundation area and ran into solid rock (or shelf as they say in Maine). The rock looks like it is some kind of gneiss with nice veins of crumbly quartz and iron. This nice rock has a few low spots in it that collect water and before building a house it is something that should have a drain which, means cutting a drain in solid rock.

The rock is tough and their previous attempts to break it up using rock bars, mauls and a skill saw with a diamond blade were unsuccessful. So for round two, my friend rented a 14 inch gas powered concrete saw. The saw is a wet or dry use saw, but since we were no where near running water our cuts were made dry.

Our initial strategy was to make saw blade deep cuts on either side of the trench we were cutting then make perpendicular kerf cuts. This worked great for the first pass or two. Then the rock got harder or the angle was not longer good enough and by the third cut down this technique was useless.  The adaptation was to make lots of long parallel cuts close together and the use a rock bar to break the fins. Often we could break the fins out across the entire trench with this method. It made a lot of dust but made lighter work of the rock removal.

Two main areas required most of the work. In each spot we had to go down 14 to 16 inches. This meant that we had to terrace the trench so that the saw could keep fitting deeper as needed. Amusingly there were parts of the rock that had an iron layer and so big chunks would come out along that layer very easy. This was welcome relief when it happened.

The completed trench

 Originally we thought the work would take two days at most as it looked like there was only a couple high spots that needed to come down to allow for drainage. We did our guesstimating without the use of a transit or other mechanical help to aid our calibrated eye levels.  The project ended up taking four days and lots of dust. All the work was well worth it as there is now a trench that will keep the foundation of their happy home dry.