To position the Diamond Pier unit, Cape Cod remodeler Mike Horgan digs a small hole in the ground (left), sets the precast concrete footing onto the soil (middle), and levels the footing with a torpedo level (right).
Horgan taps a hard plastic point into the end of on of the Diamond Pier’s four hollow galvanized steel pins.
Setting the steel pins into the holes on the Diamond Pier hub provides leverage that makes it easier to carry and set the hub or to adjust its position.
With the concrete hub in position, a sledgehammer serves to start the process of driving the pins into the subsoil.
Using an electric jackhammer with a specially designed bit that fits over the Diamond Pier pins, Horgan works his way around the hub and drives the pins into the earth in stages. Driving the pins takes about five minutes.
Pins are set almost flush to the concrete hub, using the depth of the driving bit on the jackhammer as a gauge. Fully driven pins project five feet into the ground in this case, but the pins for a larger unit with greater bearing capacity may go much farther down.
The installer sets rubber caps over the steel pins by hand. At this point, the caps can be removed so an inspector can verify the pin depth, but after the inspection, the caps will be tapped down and the joint sealed with adhesive sealant.
“When the inspector comes out, he can just stick his tape down the pipe and see that he has what he wants,” says Horgan. That means that Horgan’s crew can carry on with framing on top of the piers immediately, without waiting for an inspection.
Horgan installs a galvanized Simpson post base connector on top of the newly installed pier, first placing the base (left), then installing a washer and nut over the cast-in-place bolt (center), then inserting a standoff base (right).