How To Build An ADU

An accessory dwelling unit (ADU), also known as a granny flat or in-law suite, is a secondary housing unit on the same grounds as an existing single-family home. These dwellings can be in a converted basement, an attic, or a garage.  They can also be attached to the primary house or can be a free-standing detached small home in the backyard.  ADUs offer many benefits, such as providing affordable housing options, enabling multigenerational living, providing rental income to homeowners and also increasing property values, and more. Today, we’ll explore the process of building an ADU on your property.

The Cost

Several elements impact the cost of building an ADU. Location, materials, site preparation, foundation type, utility connections, permitting fees, and interior finishes all contribute to the overall cost of investment, as well as working with contractors and other professionals. However, even high-end ADUs can cost significantly less than one may think. It can be difficult to estimate the overall cost of adding an ADU to your property due to all of the possible variables, but it’s important to have a rough estimate so that you can apply for financing and create your project budget.

Each ADU, and the property it's being built on, is unique and often designed to suit your personal needs. Moreover, the requirements of each jurisdiction are different.  As a result, the cost of construction can vary widely and can cost between $60k and $225k, or more, depending on size, location, and other factors. 

Comparing the cost of building with the long-term investment of adding an ADU is also crucial. While constructing an ADU requires financial resources upfront, ADUs increase property value, can be used as rentals for extra income, and provide housing for much cheaper than the current market would allow. Overall, investing in an ADU is a financially sound decision that offers both long-term benefits and potential financial gain.

Makara ADU has created a turn-key process that will deliver an amazing finished product and handle everything from design to permitting, to construction and delivery....all for one simplified, stress-free low price. 

The Process

Research and Feasibility

When considering an ADU, note that not all jurisdictions permit ADUs, and each county or city has its own set of rules and guidelines. To start the ADU process, you should research local zoning laws and permitting requirements, which vary significantly by county and city. Homeowners must verify they can legally build an ADU on their property before proceeding further. Researching these regulations upfront prevents costly surprises down the road and ensures your ADU complies with ordinances. 

There may be rules about ADU size, height limitations, setbacks from property lines, or design standards that may affect your plans and design, so it is important to know what’s allowed before designing your dream ADU. If you belong to a homeowner's association (HOA), check if there are any restrictions or specific approvals needed to build an ADU. You may need HOA permission before constructing an ADU on your property.

After having an idea of what would be allowed on your property and a rough estimate of what it would cost, you can begin to plan your design.

While someone could build an ADU themselves, having a contractor that specializes in ADUs can be invaluable. These experts assist with feasibility analyses, budget estimates, architectural plans, permitting, and project management. They have familiarity with ADU-specific regulations to help streamline approvals without getting stuck in red tape and will include design-build as part of their offerings. Working with an experienced ADU expert can help you with researching laws and discussing the feasibility of your dream ADU.

Design and Planning

During the design and planning process, you would want to look at things such as the purpose of the ADU, the size, what amenities would be included, what type of materials would be used, and securing financing. Working with a reputable and experienced ADU builder/designer is the most efficient and effective way to add an ADU to a property. Companies specializing in building ADUs have vast knowledge regarding ADUs and have the most to offer potential clients. Additionally, ADU builders should have many examples to look at and get inspiration from.

Securing financing for building an ADU must also be done before any construction can begin. Financial assistance could include low-interest loans from banks or credit unions, as well as grants offered by various organizations. Makara ADU offers financing options in addition to building and design, so all ADU needs can be handled in one place.

Permitting

Understanding local regulations is crucial when building an ADU. It’s important to research and comprehend the specific permitting process required in your area. Securing necessary permits can be a time-consuming and complicated process, but it must be done before beginning any construction.

Detailed plans must be submitted to local agencies to obtain zoning permits, conditional use permits, site plan approvals, building permits, and other more specific permits such as coastal building permits, if required. The permitting phase usually takes 60 to 90 days but can take up to 12 months. While someone could apply for these permits themselves, there are a lot of details that must be submitted correctly to avoid lengthy delays. Contractors like Makara ADU are experienced in handling these permits and can help avoid costly delays.

Construction

The ADU build process proceeds through several key phases, including site preparation, foundation work, framing, utility installation, and interior finishing. The actual construction phase can vary depending on what kind of ADU is being built, but typically the process is as follows. 

Starting with site preparation, contractors begin clearing and leveling the ground, trenching for utilities, installing the groundworks, and then pouring the concrete slab foundation reinforced with steel rebar once inspections are completed. Framing follows, assembling the wall, and roof structures (often this can be done in a modular or panelized approach) to create the ADU skeleton.  Next electrical, plumbing, and HVAC subcontractors rough in the infrastructure electric, plumbing, and HVAC within the new framing.   Once the rough-in is complete, the building is ready for Close-in. Upon approval of the Close-in inspection, insulation is completed and then drywall sheathing is hung and finished. Trim carpenters install the trim and then the crews install cabinetry, interior doors, baseboards, flooring, and tile. Painters apply the finishing coatings and decorative treatments. Counters, electric and plumbing fixtures, and appliances are installed. Finally, the owner and contractor perform a series of punch list walkthroughs and repairs culminating in the final inspections required to occupy the ADU. 

Careful project management and supervision keep this sequential process on track and contractors work with subcontractors to ensure everything goes smoothly.

Timeline

With a contractor specializing in adu construction, a certificate of occupancy can typically be issued in about 6 months. Partnering with an ADU design-build firm, such as Makara ADU,  facilitates a more streamlined process that includes a 60-90-day process for schematic floorplans and renderings, permit applications, and securing plan approvals before construction commences. Actual build-out of the accessory dwelling unit will generally take about 3-4 months from permit issuance, based on the unit's total square footage and features. A detached ADU typically takes longer than modest conversions of existing spaces. 

As finish materials are installed, builders ready the site for final inspections, confirming all work meets current building codes and matches accepted plans. Once the project passes inspection, last-minute touch-ups, deep cleaning, and final walkthroughs with the owner wrap up the project. Builders then submit the final inspection results to the permitting office to attain the certificate of occupancy. This last milestone officially completes the project and allows the new ADU to be inhabited as a legally sanctioned rental or additional living space.

Constructing an ADU requires careful planning and partnership between homeowners and experienced builders.  Following proper protocols for feasibility analyses, permitting, design, utility connections, construction, and interior finishing facilitates an efficient process that meets codes and satisfies all stakeholders. With realistic budgets and timelines and clear collaboration, ADU projects can provide beautiful, functional secondary housing options.