Hand-Dug Caissons, 24 Feet Deep: Building a Pool Foundation on a Hollywood Hills Slope Nobody Thought Was Buildable.

This is what we walked into before a single shovel hit the ground. Steep grade, dense growth, and a lot of unknowns. The first step was getting our team on-site to assess conditions. With soils testing underway and plans being developed, walking the site together helped us spot constraints, evaluate access, and coordinate the best path forward.

Drone shot of the slope before we broke ground. All of this would eventually be excavated to install a deep pile-supported foundation system. The hillside didn't look like much here.

Same angle after we cleared the vegetation. Clearing the site was the first major step, exposing the hillside, opening up access for our crew and revealing the space that would eventually become the project's centerpiece.

You can see just how much of the slope was basically unusable. Too steep to do anything with. The client knew they wanted to use this space; but weren't sure what was possible.

Temporary stairs in, plywood safety wall up, and the green pipe running down the hillside became our material chute, moving excavated soil straight into the bin. When there is no equipment access, you learn to work smarter.

Every one of these six piles was dug by hand, ranging from 15 to 24 feet deep depending on location. On terrain this steep, no heavy machinery could reach the site, so the crew dug the piles and dropped each rebar cage in by hand. A soils engineer verified each one. Together the piles support a cantilevered tie beam and footing system built for the above-ground pool shell.

Aerial view of the full row of piles lined up along the future retaining wall footprint. Every one of these is placed exactly per the engineered layout.

Grade beams formed up 8 feet above grade. Once the concrete is poured, they will create the flat, level base the pool will eventually sit on.

This is a shot of the concrete pour for the piles. Once this concrete cures, these become the primary load-bearing elements for the retaining walls, beams, and the pool.

Concrete going into the grade beams. That steel ties this beam directly into the piles below and the pool shell above. Everything is connected into one system.

Another pour shot, but you can see a sneak peek of the view and the reason why our client wants a pool up here.

Now for the shotcrete. This is how we form structural walls against a hillside. We use high-strength concrete sprayed under pressure, so it packs tight even on a vertical face.

After the shotcrete goes on, the wall gets smoothed out. Smooth surface, proper curing, built to last.

The base of the pool’s foundation is complete! The piles, grade beams, and retaining walls are all in. The exposed steel is capped and ready for the pool contractor to take over.

The foundation is in. This is the moment before it really starts to look like a pool.

Pool shell rebar and formwork going in. This ties the swimming pool structure directly into the foundation system we engineered and built.

Aerial of the same phase. You can really see here how everything ties back into the deep foundations below.

Concrete painted white to match the aesthetic of the home.

Pool shell, infinity edge, spa, and steps. All done. We didn't build this part, but all of it is sitting on the pile-supported system we engineered and built.

The client brought in a muralist to finish the space. This is the part where it starts to go from a construction site to a dream backyard.

Final drone shot. Pool filled, furniture in, mural complete. What was once a steep, unusable hillside is now a dream backyard oasis.

Here's the completed project. A huge thank you to our client, whose vision made this incredible space possible. Projects like this are built on collaboration, and it's been a pleasure to be part of the journey from concept to reality.

Our team got invited back to enjoy a quick dip in the very pool they helped build. Moments like this make all the hard work worth it. The clients are thrilled; we're thrilled. Job done.

Want to see more start-to-finish structural projects like this? Drop a comment below and ask us anything about the engineering or construction process.