Add a Full Living Space to Your Lot

Custom ADU builds designed for Portland homeowners looking to expand their property's potential.

You've outgrown your current home layout in Portland, or you need a separate space for aging parents, adult children, or rental income. An accessory dwelling unit gives you a complete second residence on your existing lot without relocating or purchasing new property. Portland's zoning allows for this type of addition in many residential neighborhoods, and a well-designed ADU can serve multiple purposes over the years as your household needs change.

Sparrow Remodeling handles every phase of ADU construction, from initial design and permit applications through Portland's review process to final inspection and occupancy approval. We build detached units, attached additions, and converted garages, all meeting Maine state building codes and energy standards. You choose the size, layout, and finish level that fits your budget, and we provide transparent pricing with no surprises during construction. The result is a fully functional living space with its own kitchen, bathroom, sleeping area, and utilities.

If you're ready to add livable square footage to your Portland property, reach out to discuss your lot and what type of ADU works best for your goals.

What Actually Happens During an ADU Build

We start with a site assessment of your Portland property to determine setbacks, utility access, and drainage requirements. Once you approve the design, we submit permit applications to the city and coordinate inspections at each construction phase. Foundation work begins after permits clear, followed by framing, roofing, exterior siding, and then interior mechanical and finish work. You see progress weekly, and we adjust schedules around weather delays common to Maine winters.

When the build is complete, you have a separate entrance, dedicated heating and cooling, insulated walls and roof rated for Portland temperatures, and all appliances installed and working. The unit passes final inspection, which means it meets occupancy standards for safety, ventilation, and egress. If you plan to rent the space, it's ready for a tenant the day you receive your certificate of occupancy.

We use local subcontractors for electrical, plumbing, and HVAC work, and all materials are sourced to withstand freeze-thaw cycles and coastal humidity. The structure is built to last decades, not just meet minimum code. Sparrow Remodeling does not handle property management or tenant placement, but we do provide documentation for appraisals and insurance updates once the ADU is finished.

Questions That Come Up Before You Commit

Homeowners in Portland often ask the same practical questions before moving forward with an ADU build, especially around timing, costs, and what the process actually requires from them.

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How long does it take to build an ADU in Portland?
Most builds take four to six months from permit approval to final inspection. Permitting adds another six to eight weeks depending on city review timelines and whether revisions are needed.
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What size ADU can I build on my lot?
Portland zoning typically allows ADUs up to 800 square feet or a percentage of your primary dwelling size, whichever is smaller. We measure your lot and confirm setback rules before designing anything.
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What utilities does the ADU need?
The unit needs its own water line, electrical panel, and heating system, though these often tie into your existing services. We coordinate utility hookups with the city and install separate meters if you plan to rent the space.
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Why would I choose a detached ADU over a garage conversion?
Detached units offer more privacy and flexibility in layout but require more site work and higher construction costs. Garage conversions use an existing foundation and roof, which reduces both cost and build time.
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What happens if my lot has drainage or slope issues?
We assess grading during the site visit and plan foundation adjustments or drainage solutions before breaking ground. Sloped lots in Portland often require extra excavation or retaining walls, which we include in your estimate upfront.

Sparrow Remodeling builds ADUs throughout Portland, working with lots of all shapes and sizes. If you're ready to explore what's possible on your property, contact us to schedule a site evaluation and review your options.