We receive numerous queries from prospective clients wishing to convert their current garages into Accessory Dwelling Units (ADUs). The main reason people desire to pursue this way is that they believe it would save them money on building costs by reusing an existing structure. Although this is a terrific goal in theory, for almost every query, we advocate against doing a conversion and instead demolishing the garage and building the new ADU from scratch. There are numerous grounds for this recommendation.
Working inside existing structures requires more work.
Garages were not designed and built for living, and many are older and require major repairs and adjustments to make them habitable.
In our experience, upgrading garages is frequently difficult and complex. Garages were not meant or built to be lived in, and many are ancient and require considerable repairs and modifications to make them habitable. Documenting the existing structure takes time and requires repeated travels to the site to verify dimensions throughout the project. Roofs are frequently in bad condition and require repairs or replacements; there are no windows, or if there are, they are small and in odd positions. Existing walls are often not physically solid, and many garages lack sufficient structural footings. There are normally no plumbing hookups, and even if there are, cutting through the concrete floor is required to bring the pipes into the proper locations for building kitchens and bathrooms.
All of these factors, as well as other potential issues, add to the design team’s workload as we document the current space and attempt to create a new housing unit within its constraints. It is more effort for the contractors because they must work with what they have and are limited in their equipment and construction methods. There is more manual labor required, as well as more unique measurements and one-of-a-kind pieces, which causes construction to take longer and cost more.
As an example, we recently developed an ADU Garage Conversion for a property in Orange Country’s district. As we examined the existing structure, we discovered that there were insufficient footings under the garage’s external walls. The only way to add footings without damaging the structure was to manually dig 4-foot portions beneath the existing walls, pour a new concrete foundation, and then dig the next 4-foot section. This is labor-intensive work that takes a long time. This alone adds around $12,000 to development costs.
This is one example of added work and associated costs. Furthermore, more design time is required for architectural and structural engineering, permit reviews can take longer as they check the plans to ensure they meet today’s code and structural requirements, and construction can often take just as long and face a variety of difficult conditions – all of which add cost and make these projects less affordable than they appear at first.
Garage conversions won’t save you money.
Based on recent projects, we’ve discovered that converting an existing garage is frequently cheaper than removing the garage and creating a new ADU, and the procedure is considerably more challenging.
Most ADUs in Orange County cost between $175,000 and $250,000 to build (or more if you like higher-end finishes and products). Labor expenses in this tight market, import tariffs, and strain on material supply have all contributed to major cost increases in recent years. These figures exclude design expenses (estimated to be around 10% of building costs) and permitting fees (between $6,000 and $12,000), which vary depending on the design and existing conditions. Even garage conversions fall within those budgets. There may be some savings if the old structure is up to date and in excellent condition, but this is rarely the case. Garages typically have damaged roofs or cladding, no windows or windows that need to be replaced, insufficient construction, and cracked, damaged, or non-existent concrete slabs and foundations. Often, upgrading and repairing the current structure costs the same as saving money by reusing the garage.
If you’re spending the same money, why limit yourself to working in the garage when you could create a custom ADU that is more beautiful, responds particularly to your needs, and blends in better with your property?
New construction can be healthier, more comfortable, and more environmentally friendly.
One of the most energy-intensive things we do is keep our buildings cool in the summer and warm in the winter.
With all of our projects, we approach the design process with the goal of creating attractive places that are pleasant for occupants, have a healthy indoor environment, and are as sustainable as possible while staying within our client’s budget. Achieving these objectives is frequently more complex and difficult when restoring an older structure rather than developing new. Most older garages are constructed of 2x4s, whereas modern dwellings often have 2×6 thick walls and 2×12 roofs. This extra wall and roof hollow space enables us to better insulate our buildings, which is the first step toward producing pleasant and sustainable structures.
One of the most energy-intensive things we do is keep our buildings cool in the summer and warm in the winter. Increasing the R-values of our walls and roof (a higher R-value indicates better insulation) is the most cost-effective and simple solution to cut energy consumption, improve interior comfort, and minimize CO2 emissions.
To achieve equivalent insulation values in a garage conversion project, new deeper studs and rafters are sistered to the existing framing, effectively re-framing the entire building from the inside. The option is to simply insulate the existing wall cavities, independent of structural thickness. This results in lower R-values, draftier dwellings, and more dramatic temperature fluctuations due to changing weather and external temperatures. This can cause the ADU to seem too chilly or too warm, or it may use a lot of energy to heat and cool the area. Remember that increased energy consumption results in higher energy costs throughout the course of the building’s lifetime. This increase in life-cycle expenses should be considered when budgeting for your project.
You don’t really get what you want
Garages are not intended, built, or sized to accommodate people or the rooms and spaces required to provide a great living environment.
Being constrained to a garage’s current size, form, dimensions, and height can be exceedingly restricting. When we have worked on these projects in the past, we frequently begin the design process with our customers by creating layouts inside the current garage footprint, and they become upset as they discover more about the design’s constraints and limits. The spaces turn out to be less than they expected, and the complexity of adding onto, or lifting the roof to create extra space, ended up being pricey and frequently much out of their budget. Rather than limiting the possibilities by continuing with the current garage, we urge our clients to design a new custom ADU that is tailored to their individual wishes and needs, as well as the unique features of their land.
Converting a garage into an ADU has its time and place. Sometimes it is the only choice to build a second unit on the property. Sometimes the garage is newer and in better condition, making it easier to convert on a small budget. However, in our experience, these projects are usually more hassle than they are worth and do not save money. For these reasons, we typically propose designing and building a new ADU that is exactly what you want, rather than confining yourself to working within the current limits of a garage structure.
