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Hillside Homes: How to Remodel with a Slope

Older homes, steep hills, and sloped lots are all common features in the Bay Area. Older homes on a hill present unique challenges for hillside building and remodeling. However, a hillside home has many advantages, such as the potential for distinctive architectural details, an abundance of natural light, and breathtaking views. Update your dated hillside home and turn it into a showcase worthy of a magazine spread!

Utilizing Space in a Hillside Home

Many hillside homes in the Bay Area have a modest horizontal footprint but generous vertical space. Utilizing the area below grade for your remodel is one way to make the most of the space that is available. Some older slope homes are built on stilts. Replace this empty, unfinished space with finished interior space to increase stability and square footage.

You can use the lower level as a garage, game room, guest room, or home office. Another option is to turn the space into an Accessory Dwelling Unit (ADU).  In April 2019, the Bay Area Council launched the Casita Coalition to promote the construction and use of ADUs in order to increase the ratio of affordable housing in the city and surrounding areas. Cities in California are permitted to include ADUs in their calculations for regional housing needs allocation as a form of affordable housing.

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Maximize Your Top Floor When Building into a Hillside

The top floor space often affords the best view in a hillside home. Create or expand outdoor living space by constructing a deck above the new ground floor or a rooftop deck. After all, that view will make all the work and changes worthwhile. 

Your architect can redesign your floorplan, or even build upwards and down, to utilize the space on your hillside property. With global warming, you can change the interior flow and take back top-floor space by moving the bedrooms closer to ground level. Upper-level living spaces will take advantage of the views, while sleeping areas will be cooler and more comfortable. 

If this is your forever home and you want to age in place, consider including an elevator in your home design. Just because your hillside home includes stairs doesn’t mean it can’t be accessible in the future.

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Hillside Home Construction Planning

Slope remodeling requires special consideration at every stage of the process, from planning to construction to completion.


Work with your engineer to ensure that water runoff is safely routed around the home’s structure to ensure stability. If possible, consider installing a foundation drainage system that drains away from the home’s foundation.

Earthquake Support

The obvious truth is that homes built on hillsides are more vulnerable to earthquake damage than homes built on flat land. Extra precautions must be taken to ensure safety and stability. The foundation must rest on bedrock deep beneath the surface in order for the house to be stable. 

How deep? Often, you don’t know until you dig, but your structural engineers will guide you. They will use seismic bracing to keep the home as stable as possible during earthquakes. 

Changes will result in new code requirements for hillside properties to be safe in earthquakes because any remodeling requires permits. Learn more about the Alameda County residential permit process and the Contra Costa County residential permit process.

Erosion Control

Every property owner is concerned about soil loss, but sloped lots are particularly vulnerable to it. Knowing the type of soil on your lot will help you decide how to build to maximize stability. A retaining wall can hold the soil in place to minimize erosion.

At Drafting Cafe Architects, we are very familiar with the ins and outs of hillside building and remodeling. Our team of architects and engineers can design a plan to safely make your house on a hill into the home of your dreams.


Get in touch with us. We would love to help you get your project off the ground