Up in the Air
The existing frame had to be lifted and temporarily supported while foundation work took place underneath
The need for a new foundation led to lifting and temporarily supporting the existing frame for about two weeks.
While the foundation change order was being prepared, on-site attention turned to preserving the existing wall and roof framing of the original beach cottage. During demolition, the crew discovered that the lap siding had been nailed directly to the studs, so when that siding was removed, the frame, though not in danger of collapsing, was wobbly. To stabilize it, they attached diagonal bracing to the inner sides of the studs and rafters.
The original beach cottage lacked sheathing or diagonal bracing. After removing siding and interior finishes, the crew stabilized the framing with diagonal bracing.
After Change Order One was signed, approving construction of a new foundation under the original section of the cottage, it became clear that the frame would have to be lifted and temporarily supported while excavation and masonry work took place underneath. What remained of the original structure was small (22’6” x 18’6”) and relatively light, so the plan was to use the Dingo to make the lift and use CMUs as temporary supports.
The first step was to create a girdle around the building by fastening 24-foot 2x12s to the studs. The crew used 3-inch structural screws to fasten the band about 6 inches above the bottom of each stud. On the two short walls, the 2-bys extended beyond the corners, which provided a purchase point for lifting. After cutting the nails to detach the studs from the sills, and removing the infill CMUs from the foundation, the frame was ready for lifting.
To prep the frame for lifting, the excavation crew used 3-inch structural screws to fasten 24-foot 2x12s in a band around the perimeter (left). Before lifting the frame, the nails holding the studs to the sill were cut, and infill block from the foundation was removed (right).
The lift itself was done using the arm of the backhoe, which was still onsite. “I had a recovery strap in the truck,” says Mike Eckert, “so we did one corner at a time.” The building was light enough that it was easy to raise each corner a full 18 inches before moving to the next one. CMUs were used to build cribbing that served as temporary supports. With the frame fully supported on CMU cribbing, workers removed the sills and remaining piers, and prepared to dig the footings.
The lift was made by going around the building once, lifting each corner 18 inches using a strap and the arm of a backhoe (left). Cross-stacked CMU cribbing provided temporary supports. With the frame temporarily supported about 3 feet off the ground, the demolition crew removed the old mudsills and the remaining infill CMUs (right).
Up in the Air
Eckert had hoped that the structure would only have to be temporarily supported for about a week, but that’s not how it happened. “The house was in the air for about 10 working days,” he says. “We had an ungodly amount of rain—something like 11 inches total.” The rain not only delayed progress on the foundation, it created some anxiety around the fact that the building was 3 feet off the ground. “I’d be lying if I said I wasn’t worried about all that rain,” Eckert admits, “but the pads held and we got it down onto the new foundation as fast as we could.”
As it turned out, that required lifting the house a second time, because a few days after the initial lift, the decision was made to change from 4 to 5 courses in the new block wall. “That made the new foundation height the same around the entire building,” Eckert says, “and avoided having to dig more out of the crawlspace.” But it also meant they had to go around the building and lift it another 8 inches. The excavating equipment was no longer on site, so Eckert decided to wait to make the additional lift until the foundation was in place. “We used an auto jack on one side,” Eckert says, using the new block wall and mudsills as a base. That proved to be so easy, Eckert changed the plan: “We just used four people to lift the other side.”
We wish we had a photo, but while helping list the building, Eckert opted not to let go with one hand to take a selfie.