Hillside ADU Design Process: The First Three Drawings, Creating Schemes
Schematic Design is the phase when the project starts to take shape. We start with a list of the rooms and spaces you want and look at the ideal relationships between the rooms (the bathroom wants to be next to a bedroom, for example, or the living room wants to open onto an outdoor deck). This is an effort we call programming.
After we know what is going inside the home, we dive into where we will build the ADU while minding all of the existing conditions such as height and square-footage limits or the location of neighboring trees and property setbacks.
One of our projects, a hillside ADU, has a large and open backyard, but the setbacks, the topography of the sloping site, and the desires for views started to limit where and what we could build. We used these limitations to help us create schemes that would create a great home that is unique to its site.
Above is the existing site plan with the site of the future ADU highlighted in yellow.
The hillside ADU is a 1,000-square-foot home with 2 bedrooms and 2 baths and highlights the views of the San Francisco Bay while controlling the afternoon sun and summer heat. What makes the property interesting is the steep slope, which creates a place that gets the most out of the views without being blocked by other homes or trees. The three schemes each have something unique while addressing costs and constructability.
Scheme One: One Story
Our first scheme focuses on a single story, which creates a larger footprint (and need for more sitework) but simplifies the architectural form, making construction cheaper.
We show two options for the scheme to highlight that the schematic design process is all about finding the best parts and pieces of each scheme and combining them in to one scheme. One of the options splits the layout into two areas with the bedrooms on one side and the great room on the other. Our second option splits the layout into three areas, placing the bedrooms on the ends and separating them with the great room.
Scheme Two: Two Stories
The second scheme is all about a smaller footprint, looking at a two-story layout where the bedrooms could be either on the upper or lower story. The smaller footprint would allow us to do less sitework, but we start to see potential issues with the height limitation for El Cerrito. The option can be firmly embedded in the hillside with a walk-out first story in the front and second story in the back.
Scheme Three: Split-level
The third scheme is a compromise, a split-level home that is more shaped to the slope of the property. This option adds some visual complexity and naturally creates opportunity for clerestory windows and interesting interior spaces. It could also reduce the cost of sitework. Like the stacked scheme, it would require some dedicated area for stairs but allows some spaces (such as the great room) to have double-height ceilings, making the ADU feel bigger than its 1,000-square-foot limit.
Evaluating the Options
We worked with the client to evaluate the three options, and with the help of a number of precedent images and photos, chose to move forward with the first scheme. The client liked how a single story meant less digging down if we put it on posts and how it had a simpler layout. They also liked several parts from the other schemes, such as entry from the view side of the ADU and the bedroom layout options. The biggest attraction, however, was the simple architectural form and the deck out front.
In our next post, we’ll explore how we developed that scheme into a layout and design that really matched the client’s needs and aesthetic preferences.
Building an ADU is one of the best investments you can make for your home and for your family. Schedule your free call today to discuss the possibilities for your property.
