Commack has one quirk that changes the entire economics of a garage conversion: the hamlet is split between the Town of Huntington and the Town of Smithtown. Same school district, same neighborhoods — but which side of the town line your parcel sits on determines whether you can apply for New York's $125,000 Plus One ADU grant (Huntington participates; Smithtown currently doesn't).
Program status — verified September 2026
Plus One ADU is a New York State program (an $85 million allocation through the Housing Trust Fund Corporation) but it is run town by town, and each town's intake opens and closes on its own schedule. As of September 2026 on Long Island: Huntington and Riverhead are accepting applications; Brookhaven, Islip and Southold are closed. Babylon, East Hampton, Shelter Island and Southampton run their programs through Community Development Long Island rather than the Long Island Housing Partnership.
The $125,000 is a cap, not an amount every applicant receives, and it is awarded as a grant. Huntington's published guidelines cap household income at 100% of Nassau/Suffolk area median income (2023 HUD limits: $109,400 for a one-person household, $156,300 for four) and require that you have owned and lived in the home for at least one year. Applications go on a first-come waitlist and are then re-ranked on priority points, including whether the unit will be affordable at or below 80% AMI and whether it can be permitted without a zoning variance. Municipal code always overrides the program guidelines. Verify your town's status before you budget around a grant: LIHP (631) 435-4710. We also check it for you on the walkthrough — see our Plus One ADU grant page for the eligibility checklist and what the build costs if your town's round is closed.
The fastest way to check: look at your property tax bill or survey. Suffolk parcels in the Town of Huntington carry tax district 0400; Town of Smithtown parcels carry 0800. Or just ask us — we confirm it in the first five minutes of a walkthrough.
Commack's Housing Stock Was Practically Built for Conversions
Commack's postwar hi-ranches, splanches, and split-levels share a feature that makes conversions unusually clean: ground-level garages already inside the home's envelope. That means:
- No structure to build — foundation, roof, and three walls already exist and are already tied into the house.
- Short utility runs. The garage sits next to existing plumbing and the electrical panel, which keeps rough-in costs down.
- Natural separation. A lower-level unit with its own entrance under the main living floor is the classic hi-ranch accessory-apartment layout — private for them, private for you.
Typical Commack conversion budgets run $50,000–$95,000 for a ground-level one-bedroom with full bath and kitchenette, 8–12 weeks of construction after approvals.
The Rules on Each Side of the Line
- Huntington side (district 0400): applications go through Huntington's Accessory Apartment Bureau — owner-occupancy, code conversion, parking review, CO. And you can apply for the Plus One grant: up to $125,000, forgivable, which can cover the whole build. Grant guide.
- Smithtown side (district 0800): accessory apartments are permitted under Smithtown's own code with owner-occupancy requirements — no grant currently, but the conversion still pencils out on rental income of roughly $1,600–$2,200/month. Smithtown specifics here.
Either way, the build itself is the same work — the paperwork path and the funding change. We handle both.
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Frequently Asked Questions
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Work With Alec's Construction
This guide is written by the crew that does the work. See Alec's ADUs service — accessory apartments, garage conversions and grant paperwork. Licensed and insured on Long Island, one crew start to finish, free walkthrough and a written estimate inside 48 hours.
Booking the cold months now: we also handle Additions & New Construction and Bathroom Remodeling.
We pull the permits on our own jobs — if you need the building department for your town, we keep a current directory of all 23 Long Island permit offices.
Also Serving Commack
- Basement Finishing in Commack — egress, ceiling height and moisture
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- Gutter Installation in Commack — seamless gutters, fascia and drainage
- House Painters in Commack — exteriors while the fall window holds
- Interior Painting in Commack — the right work for the cold months
- Kitchen Remodeling in Commack — cabinets, counters and layout
- Roofing in Commack — tear-offs, repairs and storm damage
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