Slideshow: Replacing a Beach House Foundation

Shane Fenton and Chris Mitchell of Thompson Johnson Woodworking rebuild the foundation of a Maine island house on a waterlogged site, a stone's throw from the salt water of the Casco Bay.

House Before Remodel

The project house before demolition of the existing porch. Drainage on site was an obvious problem; hidden issues with the foundation piers soon came to light.

Pier Problems

Concrete piers supporting the building's posts looked a little sketchy, so the plans called for replacing a few piers if needed.

Pier With No Footing

As the job progressed, it became evident that most of the concrete piers supporting the house were deficient. This pier, for example, had no footing and did not extend below the frost line.

Pier Damaged by Frost Action

Frost action and the movement of heavy, saturated soil cracked this existing foundation pier, which apparently lacked any steel reinforcement.

New Pier Foundation

On the side of the house closest to the ocean, the crew set new foundation piers to support an open post system for the building's porch and roof.

New Footing Forms

Working in soggy, heavy clay soils, the crew formed up footings for a new concrete retaining wall and foundation to support the new addition.

Freshly Placed Footing

The new footing for the porch foundation and retaining wall sits in the wet trench. Drainage is a problem on this site, which is located just a stone's throw from the salt water of the Casco Bay.

New Foundation Wall

Wooden forms in place for a new foundation wall, designed to hold back new fill as well as support the remodeled house structure. Because of zoning restrictions, the new structure had to stay within the footprint of the existing house.

New Foundation Wall

Wooden forms for a new foundation wall, designed to allow for re-grading the site as well as supporting the reconstructed porch and kitchen addition.

New Foundation Wall

The poured concrete foundation wall after backfill. This wall is designed as a retaining wall, but fill could not be added to the site because of environmental rules.

New Foundation Wall

This portion of the foundation reconstruction is ready to serve as a retaining wall as well as a support for the building. But plans to re-grade the site were put on hold because of a city environmental review.


The crew temporarily supported the existing porch roof, while completely reconstructing the lower supporting structure and deck.

Framing the Deck

With the house temporarily supported on jacks and the new post structure framed in for the post, the crew hurried to build the new porch before winter weather set in. To the rear is the Casco Bay, just a few feet away from the property.

Cold, Wet, and Muddy

Chris pulls chunks of ice out of the excavation.

Mucking Out

Chris throws out a shovelfull of ice and mud from the excavation. After precast post bases were set, the holes filled up with groundwater overnight.


Chris vacuums water out of the excavation. After a sump pump got clogged with silt, the crew switched to a Ridgid shop vacuum, which handled the muddy water with ease.

Drilling for Rebar

Chris drills holes for steel reinforcement in the precast footing pad using a hammer drill.

Cutting Rebar

Chris cuts pieces of half-inch reinforcing steel to length with an abrasive grinder wheel.

Setting Rebar

Chris pounds rebar pieces into drilled holes in the precast footing for the new pier.

New Sonotubes

Shane brings in a new Sonotube for the replacement pier.

Placing a Tube

Chris sets a new Sonotube into place over the newly set rebar in the precast footing pad.

Setting a Tube

Chris sets a new Sonotube in place on the precast pad, slipping the tube over the steel reinforcement.

Positioning the Tube

Chris positions the Sonotube in place over the precast pad and rebar and underneath the existing wood post.

Setting a Brace

Chris shoots a screw into the temporary brace he will use to hold the Sonotube in place as he fills it.

Plumbing Up

Chris checks the newly placed Sonotube for plumb.

Checking Plumb

Shane checks his newly placed Sonotube for plumb before screwing the tube to the temporary 2x6 cross brace.

Digging for Backfill

Shane digs a shovelfull of soil for backfilling the base of the newly set Sonotube.

Frozen Ground

Shane digs into the spoil and overdig from the foundation pier hole for gravel to backfill the new Sonotube. After a few cold days, the first few inches of material has frozen solid.

Backfilling the Tubes

The crew shoveled loose gravel around the base of the Sonotubes to hold them steady as they filled the tubes with concrete.

Mixing Concrete

Chris and Shane mix a batch of concrete for their new Sonotube piers.

Bucket Brigade

Shane Fenton passes a bucket of concrete to Chris Mitchell in the crawl space. Tight conditions are typical of foundation work in the island's older housing stock.

Filling the Tube

Chris Mitchell pours concrete into the Sonotube for a new foundation pier. Each four-foot tube took about four to six buckets of concrete.

Topping Off

Chris dumps a bucket of concrete into the Sonotube.

Plumbing Up the Pier

Chris checks the plumbness of the newly filled Sonotube with a four-foot level.

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