G10 SITE PREPARATION
G1010 Site Clearing & Footing Excavation
I am fortunate to have a close friend who owns an excavation company. I should clarify by adding, “one of the best in the business.” I made the call and the next morning a ten-wheeler was backing down our driveway with an excavator in tow. A pickup truck pulled in the driveway moments later and a crew of pros wasted no time backing the excavator off the trailer.
The first tool I purchased for “the shop” was a rotary laser. I had considered renting one, but at $65 per day, I knew I would exceed the cost of buying new by the time the shop was built. I purchased the Spectra Precision LL100-2 package complete with receiver and tripod. Out the door cost was a few dollars North of $800 (at the time of this writing, 2014). I believe the pricing has come down since then.
The original layout stakes that I had previouslyinstalled only needed some slight modifications. Once the grade lines were set, the topsoil was stripped and the footing excavation began. The crew had stripped and stockpiled the topsoil so quickly that I didn't get a chance to snap a picture of the process.
The image below shows the equipment operator and foreman prepping the bottom of the footings
The trench depth appears shallow for the Northeast, but our intent was to raise the surrounding grade so the finished slab elevation of the shop would sit 2” higher than the elevation of the main house. Once the final grading was completed, all footings would bear on undisturbed soil a minimum of 48” below finish grade. There were two steps in the footings to reach this elevation.
The structural drawings called for a footing measuring 1’-2” wide x 8” thick. Reinforcing was specified as two (2) continuous #4 rebar. I’m often told that I suffer from "Overbuilding Syndrome" so it will come as no surprise that I chose to build and install a 2’-0” wide x 12” thick footing with two (2) continuous #4 bars and #4 horizontals at 24”o.c.
By the end of the day, the footings were excavated, formed, rebar installed and ready for concrete.
I contacted the building department and scheduled my footing inspections. Luckily, we were amid a “dry spell” so I wasn’t at all concerned about the trench filling with water prior to the inspection/pour. As soon as the inspector signed off, I scheduled the pour. I ordered seven cubic yards of concrete at $122 per cy (at the time of this writing, 2014). The concrete truck was barely out of the driveway when my luck and our “dry spell” ended. The sky’s opened up. Thankfully, we had seen the clouds moving in earlier and had the tarps/plastic ready.
I let the concrete set up for a day before stripping the formwork. I continued to water the surface of the footing for a few days following the pour. I’d tackle the “roots below the slab” issue later. My attention was now turned to forming the concrete foundation walls.
Takeaways:
a. What to watch out for?
- The weather. Open trenches do not like water pour in them. Nor do building inspectors. Keep a watchful eye on upcoming weather patterns and plan your excavation/concrete pours accordingly.
- Your local town building code regarding inspections. Do not proceed with any work until you have received the proper inspections.
b. What would I have done differently?
- I think I hear an echo in here. I was fortunate and everything went very smoothly. The only thing that I would have done different: Built Bigger!