ADU stands for “Accessory Dwelling Unit” or “Additional Dwelling Unit.” You may know them as backyard cottages, in-law suites, granny flats, basement apartments, or another name. Put simply, an ADU is an independent apartment on the same lot as another home.

Common motivations include to generate rental income, to provide an independent but close living space for elders, caregivers, or adult children, or simply to create a welcoming and flexible space for guests.

An ADU may be: Backyard Cottage. A free-standing structure that’s officially known as a Detached ADU. In-Home Apartment. An apartment you carve out from existing space in your home. For example, by finishing a basement, an attic, or even a garage. Also called an Internal ADU. An Addition. This is another form of the In-Home Apartment. Instead of converting existing space, you can build an addition to serve as an ADU.

In Worcester, single-family, two-family, and three-family homes generally have the right to build an ADU as long as it complies with the lot's setback requirements. Click here to read the Worcester ADU zoning by-law.

The current Zoning Ordinance is available here, which outlines what may be built. Generally, if you own a single-family, two-family, or three-family house in Worcester, you can build an ADU of up to 900 square feet, with up to 2 bedrooms. If you're building a Backyard Cottage or Addition ADU, it must be in the rear or side yard—not the front yard. Only one ADU is allowed per lot. The owner must live on the lot, either in the principal dwelling or the ADU. Any construction has to meet the other requirements of the zoning by-law, and there may be historical or environmental restrictions as well. To find out more, the first step is to check your free pre-feasibility report on our site, and then reach out to us for a conversation.

When something is allowed “by right”, that means that as long as your proposal is within the guidelines, your building permit will be approved. It’s not up to the discretion of local officials. You don’t need permission from your neighbors. You don’t have to petition the City Council.

A special permit is an additional approval that is required for projects that are beyond what is allowed by right. The special permit/site plan approval process requires an application to the Planning Board, which is Worcester's special permitting authority. If you need a Special Permit, that will often extend the approval timeline. You may need to spend more money on the design phase, and you may feel compelled to compromise or negotiate with your neighbors and local officials to get approval.

The time it takes to build an ADU can vary widely based on several factors. On average, the entire process, from planning to completion, can take anywhere from a few months to over a year. At a high level, these are the key stages and their typical timeframes: Design and Planning (1-4 months): This involves selecting the ADU type, designing the floor plan, and getting the necessary approvals and permits. The complexity of the design greatly influences this duration. If a Special Permit is needed, this phase can easily double. Construction (3-9 months): The actual building time depends on the ADU type. For example, converting an existing structure, like a basement, may take less time than building a new structure.

The cost of building an ADU varies significantly based on several factors including size, site conditions, design complexity, materials used, and labor costs. After factoring in all the costs, custom designed, new construction Backyard Cottages (Detached ADUs) typically cost in the range of $400 to $500 per square foot. Modular (factory built) housing can lower the cost of construction to as low as $300 to $350 per square foot, if you limit the degree of customization. Converting an existing space in your home, like a basement or attic, is significantly less expensive. These projects often range from $30,000 to $100,000. These are just ballpark figures to help set expectations. It's certainly possible to spend far less, or far more, depending on the specifics of your project. N.b. When getting quotes, it’s important to consider what each one does and does not include. For example, if you ask a builder for their typical cost, they will likely include only their component of the project (the actual construction), and might not include design services, surveying, permitting, site work, or other costs.

The best next step is for us to have a conversation about your goals and timeline. Then we can help you build the right team to meet those goals. Our vetted network includes experienced architects, builders, design-build firms, modular housing companies, surveyors, and more. We can also share information with you on the rent potential of an ADU in your particular neighborhood, and connect you with financing options.

Please reach out! We are always looking for high quality, reliable, trustworthy professionals. If that describes you, we would welcome a conversation.

Yes, and this can be a great choice to control costs and ensure high quality—if your project falls within their design options. We work with several excellent modular home companies and would be happy to talk to you more about this.

Enter your home address We did the hard work of digesting Newton's zoning code, checking relevant restrictions, and analyzing the dimensions of your lot to determine what you can build. Review your report Based on your individual property, we generate a pre-feasibility report that outlines what you may be eligible to build. Choose a path! Whether you want a custom, architect-designed space, a factory-built cottage, or a renovation within the existing structure, we can introduce you to our network of vetted professionals to design, build, and finance your project. Have questions or not sure how to proceed? Regardless of where you are in your journey, we would welcome a conversation with you to explore together. Contact us today.

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Please reach out! We’d be happy to discuss with you. Our phone number is 508-719-9877