If you’re a homeowner in Alameda, Albany, Moraga, El Cerrito, Kensington, Oakland, Orinda, Piedmont, and San Leandro, CA.
Hillside Garage Replacements can be Complex Projects
Unlike conventional garage replacements on level lots, hillside garage replacements are
substantially more involved. They require the demolition and replacement of large
retaining walls, excavation and the installation of drainage, as well as the more standard
replacement of framing, stucco, roofing etc.
Demolition Must Be Done Carefully
When the old structure is demolished and the foundations are removed, the adjacent soil
can be as high as 9’ and sometimes loose. If the soils are unstable, shoring may need to
be installed to hold them in place during construction.
New Engineered Foundation Retaining Walls Need to Be Installed
The new foundations are heaviliy reinforced retaining walls with drainage designed to
handle large soil pressures and potential movement.
A Complicated Scenario
In order for the new garage to meet current code, it had to be extended 2’ deep under the
(2) houses, requiring shoring of the buildings so they would be stable during
The Work Was done in Sections for Safety Purposes
To minimize the risk to the existing adjacent homes the retaining walls were built in
sections, starting with the central portion between the two houses.
A Heavily Reinforced Mat Slab Increased Stability
To increase stability we installed a “mat slab”, which is a 12” thick structural slab with
double layers of rebar. The slab becomes integrated with the perimeter foundations.
There were over 30 cubic yards of concrete just in the slab, or around 120,000 pounds of
concrete, the weight of a small house.
The Walls and Slabs are in Place and we are Ready to Build
Around 75% of the project time and cost in a hillside project went into constructing a
stable, well-drained foundation system for the new garage.
Framing is Complete
Framing and Plywood Come Next. This work took only a week or less, compared to the
2-3 month constructing the foundations.
Stucco Work and Finish Details Follow
Trim work is installed along with stucco and interior drywall, paint, garage doors etc.
We Also Created Outdoor Living Space Above the Garage
Neither of these 2 properties had any front yard space due to the slope of the lots. We
were able to construct large decks over both of the garages, adding around 400 square
feet of useable space for each home.
The Finished Product
The entire job took around 9 months to complete, but the results were very impressive.
These garages should last a lot longer than the 100 years the original ones were there, and
in addition provide new deck space and help stabilize the homes behind them.
Same Idea, But a Much Easier Project
This single car garage is not doing well. It requires a similar rebuilt, but on a much
A Snap Tie System Was Used for Forming
These forms were held together with Snap Ties, small metal rods that are braced on either
side of the plywood and remain in the concrete when poured. This system is very stable
and requires minimal bracing.