After several set backs – spring showers, existing pier cave-ins, and terrible soil – 315 Pell Street’s addition is coming out of the ground. The soil in the back half of the property was found to be primarily clay and silt that had been continuously filled over almost a century. An old creek bed is the likely culprit. Helical piers were brought in to stabilize the new addition. If you have never seen these put in before, its a cool process – not cheap but cool. Sixteen of them were drilled into the ground at varying depths until good soil and the correct psi was achieved. The depths varied between 21′ and 30′. These piers will structurally stabilize the addition permanently so the connection between the new and existing becomes important in terms of flexibility because the existing structure will continue to move. A web of rebar is created to bridge between each pier all around the perimeter of the addition. Wood form work is built around the rebar creating a continuous grade beam once the concrete is poured. Gravel is then added to help drainage around the grade beam, footings and under the concrete slab for the basement which will be poured tomorrow. The block wall and water proofing has begun as well.
Helical piers are becoming more prevalent in poor soil conditions in this area.