ADU Construction — Accessory Dwelling Units

What Is an ADU?

An Accessory Dwelling Unit (ADU) is a secondary residential unit on a single-family property. ADUs go by many names — in-law suites, granny flats, backyard cottages, garage apartments — but they all serve the same purpose: providing a self-contained living space with its own kitchen, bathroom, sleeping area, and entrance on an existing residential lot.

ADUs have become one of the most sought-after construction projects on Long Island. Homeowners are building them to house aging parents, provide space for adult children, generate rental income, or simply add flexible living space to their property. With New York State expanding ADU regulations to make permitting easier, there has never been a better time to explore this option.

Types of ADUs We Build

Every property is different, and the right ADU type depends on your lot size, zoning, budget, and intended use. We build all three major categories:

• Garage Conversions — Converting an attached or detached garage into a finished living space is often the most cost-effective ADU option. The structure is already there — we handle insulation, electrical, plumbing, HVAC, flooring, drywall, and finishes to transform it into a comfortable, code-compliant dwelling. Garage conversions typically run $50,000-$100,000 depending on size and finish level.
• Interior Conversions (In-Law Suites) — Basement apartments, above-garage units, and carve-outs from existing floor plans. These projects involve creating a separate entrance, adding a kitchen and bathroom, and ensuring proper egress, ventilation, and fire separation. Interior conversions maximize your existing square footage without expanding the building footprint.
• Detached ADUs — A brand-new, standalone structure built on your property. Detached ADUs offer the most privacy and flexibility in terms of design, but they also require the most significant investment. Costs typically range from $100,000 to $200,000+ depending on size, finishes, and site conditions. We handle everything from site prep and foundation to final finishes and landscaping.

New York ADU Regulations

New York State has been actively updating its ADU policies to address the housing shortage on Long Island. Recent legislative changes have made it easier for homeowners to build ADUs by streamlining the permitting process and reducing some of the previous barriers. However, the regulations are still complex and vary by municipality. Key considerations include:

• Zoning Requirements — ADU eligibility depends on your property's zoning designation. Many residential zones in Suffolk County now allow ADUs, but setback requirements, lot coverage limits, and height restrictions still apply.
• Size Limitations — Most municipalities cap ADU size at a percentage of the primary dwelling's square footage or an absolute maximum (typically 800-1,200 square feet).
• Owner Occupancy — Some jurisdictions require that the property owner live in either the primary residence or the ADU. This requirement varies and has been relaxed in some areas.
• Parking — Additional off-street parking may be required depending on the municipality, though recent state-level changes have reduced parking requirements for ADUs near public transit.
• Utility Connections — Water, sewer, and electrical connections must be approved. Some areas require separate utility meters for ADUs.

We handle the entire permitting process and ensure your ADU complies with all local and state requirements. Our experience navigating Suffolk County building departments means fewer delays and fewer surprises.

ADU Costs & Return on Investment

ADU construction is a significant investment, but it is also one of the highest-ROI home improvement projects available. On Long Island, where rental demand is strong, a well-built ADU can generate $1,500-$2,500+ per month in rental income — paying for itself within a few years while simultaneously increasing your property's appraised value by 20-30%.

Even if you are not planning to rent the unit, an ADU adds measurable value to your property and provides flexible space that can adapt to your family's changing needs over time — from housing an elderly parent today to becoming a home office or guest suite tomorrow.

ADU & Residential Projects

Why Choose Alec's Construction for ADU Building

• ADU Expertise — We understand the specific requirements, regulations, and construction methods that make ADU projects successful on Long Island.
• Full Permit Management — We handle every aspect of the permitting process, from initial applications through final inspections and certificate of occupancy.
• Licensed & Insured — Full liability coverage and workers' compensation for every project.
• Turnkey Service — From design coordination through construction and finishing, we manage the entire project as your single point of contact.
• Code Compliance — Every ADU we build meets current building codes for fire separation, egress, ventilation, and structural requirements.
• Transparent Pricing — Detailed proposals with clear line items. We discuss budget honestly before breaking ground.