Accessory Dwelling Unit 101: Post 2
Our first post covered what an ADU is - if you missed it, you can find it HERE. Now the question is what are the options for developing one on your property? Glad you asked! This is where things get exciting and potentially overwhelming, but don’t worry, we’re here for you. It is our mission to provide you with information you need to make a decision that best suits your needs.
In this blog post we will discuss the most common types of ADU’s, provide examples of each, and why you might consider one option versus another.
The stand alone ADU
The possibilities of this type of ADU are endless. Architecturally it could mimic the primary residence in proportion and style or be totally different and with its own modern aesthetic.
Normally sited in the backyard as a secondary structure to the main house, this type of ADU works best on larger lots with buildable area to spare. Be sure to check local zoning codes for minimum lot sizes and required lot line setbacks - stay tuned for upcoming posts about this topic. When dealing with a larger lot, one must also consider connection to existing utilities and the proximity of the new structure. How will you provide electrical, sewer, water, and HVAC to the separate structure? By definition, this type of ADU provides the most privacy for the primary house on the lot. And with it being fully disconnected, you could design separate outdoor spaces to provide total privacy.
At the end of the day, creating a stand alone structure is likely the most costly option for an ADU, but comes with its own unique advantages.
The example below is modern in form and detailing, but uses local, durable materials to blend into its context. Large windows allow natural light to penetrate the structure and make the small space feel larger while connecting the inhabitants to nature. Even in colder climates, deep overhangs protect the interior from overheating during the hottest times of day.
Photo courtesy: Dencity Design
The above / in-garage ADU
If you have plans to build a garage or have an existing garage why not utilize it as an additional living space (ADU)? ADU’s can also be located in unused overhead space or to any side of the garage depending on what fits best on the site. Similar to the stand alone ADU, this type is completely separate from the primary house, giving you all of the privacy, with the added benefit of enclosed vehicular storage. This is where the real value comes in because you were likely going to build the garage anyway. Unfortunately, comparable challenges and restrictions do apply, with unique planning considerations such as, where should the stairs be located? The building code calls for technical requirements including a fire separation between the living space and the garage area with drywall and you will need to decide if you want to heat both spaces, or insulate the dividing floor/wall.
The example below is inspired by traditional, multi-story gable structures in the surrounding area while being uniquely modern in its detailing and material usage. Making it of its time and place in history. A pronounced entrance is warm and welcoming and unexpected as it draws you inside. The large, south facing windows help make the small space feel much larger.
Photo courtesy: Webster Wilson Architect
The ADU within the primary structure
One example of an ADU within the primary structure is a connected addition to the residence. Because the existing utility infrastructure is close by, you can likely avoid some of the challenges encountered by creating a stand alone ADU, but it’s best to check with your construction professionals to make sure the systems are sized to handle increased demand. Many systems you can share between units, however, the building code will not allow you to share air, which may mean providing a separate way to heat/cool the ADU.
The example below respects and preserves the character of the historic stone farmhouse while accommodating the need for additional space. Rather than recreating what already exists, the architect pays homage to the past by using similar proportions and roof lines but creates a structure that is decidedly modern. The deliberate simplification of exterior materials relates to the historic stone construction but does not demand attention-allowing the elegant stone facade to shine. Providing a common, transparent entrance allows for the two distinct structures to coexist and limits the amount of circulation space required. The narrow attachment point creates a simple way to apply fire separation to the units. Overall, the addition ADU can be an elegant and creative way to add an additional living unit to a more restricted building site.
Photo courtesy: Neely Architecture
Probably the most simple and cost effective way to add an ADU is within a portion of your existing house - most commonly the attic or basement space. That makes sense, right? This option allows you to utilize an existing enclosure which accounts for the majority of construction costs. The likely required alterations include extending the plumbing and electrical systems to minimally accommodate the special requirements of a kitchen and bathroom. And, provide a way to heat and/or cool the units (as required) that is separate from the main living unit.
The below example is actually an ADU that Jack #1 added to his home contained within the existing basement. At 480 SF it is a cozy studio unit that opens directly to the backyard. He and his wife were then able to eliminate an interior stair coming from the main level of the house, reclaiming that space for the primary living unit. You may luck out, as they did, that your basement is already equipped with a bathroom and water and waste hook-ups for a laundry area that can be easily converted for a kitchen. The biggest challenge was how to properly provide fire and noise separation between units.
Photo courtesy: Laura Jean Media Services
If this article has got you thinking about the type of ADU that is right for you, please feel free to reach out to us at info@doublejackdesign.com! We would love to assess your building site and make a recommendation that is best for your unique situation.
Next up we’ll discuss all of the wonderful possibilities of an ADU!