Settling Cottage Repair, Windham, NH

Wednesday, December 18th, 2019 by Niles Erickson

Challenge

The owners of this summer home in Windham, NH were looking for solutions to address the piers supporting their home. Over the years, water had shifted the soils beneath the piers, and after years of expanding and contracting soils, the piers began to settle in the warmer months and heave with ice in the colder.

Beneath the home were several concrete pillars with pressure treated posts above. These posts supported various beams and the entire perimeter of the structure. They were looking for a permanent solution to replace these piers, something that would last and not settle again in the future.

Settling cottage on piers

Another challenge involved the summer home being on a lake. When water is nearby, towns and cities are very protective and there are several regulations in place in New Hampshire. Any proposed project required a Water Protection Permit from the town, and nothing new could be installed if it would disrupt or encroach on the water in any way.

Solution

Erickson Foundation Supportworks proposed replacing every pier and post beneath the home in order to permanently stabilize the lake home. Before beginning, the proper documentation was submitted to the town of Windham zoning department, and a Watershed Protection Permit was obtained.

In total, 19 EZ Post piers were installed along the perimeter of the building. The EZ Post helical piers were installed with both a Bobcat tractor, as well as with a hand held auger in tighter spaces closer to the waters edge. Each helical pier was pushed into the soil anywhere from 6 to 8 feet, well beyond the required 4 feet for standard installation of concrete pillars. They were also spaced 4 to 5 feet a part so as to evenly distribute the weight of the structure. Above the EZ Posts, 6"x6" pressure treated posts were then installed with 45 degree support limbs.

While the helical piers were installed along the perimeter, another solution was required in the crawlspace beneath the lake home. 15 SmartJacks, along with a couple steel beams, were installed to replace the failing concrete pillars and wood posts. Each SmartJack was installed over a 2' deep footing of engineered fill, which were properly compacted and prepared. Beneath each steel SmartJack post was also a large steel plate, which helps to evenly distribute the weight load across the footing. Fortunately, many of the existing structural beams were in good condition, and so the SmartJacks were installed to support these beams. In a few sections, a steel beam was required to add some additional support to the floor joists.

SmartJack Stabilizing Posts

Installation of all the piers and posts took place in December when the ground was cold and mostly frozen. This turned out for the best, as the ground beneath the lake home was very wet. Crew leader, Josh Provost, planned accordingly and made sure his team installed all the SmartJacks beneath the home first while the ground was frozen. Within a few days the ground did soften a bit and became muddy. Fortunately, the crew was able to avoid being in this mud for the majority of the project, which also meant less disruption to the property's landscape.

Overall, the project took about 10 days to complete. With the EZ Posts and SmartJacks in place, the owners of this lake home now have a stable, warrantied foundation beneath their once settling property.