Home Additions in Mount Kisco, NY
Westchester Home Addition Service Serving Mount Kisco
Second stories, rear family rooms, primary suites and garage conversions for Mount Kisco homes, designed to the Village’s RS district setbacks and coverage and permitted at 104 Main Street.
Small Lots, Clear Numbers
Mount Kisco’s one-family neighborhoods are mostly in three districts, RS-6, RS-9 and RS-12, named for lots of roughly 6,250, 9,375 and 12,500 square feet. That’s compact by northern Westchester standards, and it means an addition is designed around the setbacks from day one. The good news is that the rules are clear, and on many lots there is room to add a meaningful amount of space.
We start with your survey and total up the house, garage, driveway and patios against the 40 percent development coverage cap. Then we sketch where an addition fits inside the yards before anyone pays for drawings.
One-Family District Limits
| District | Minimum lot | Front | Side | Rear | Coverage |
|---|---|---|---|---|---|
| RS-12 | 12,500 sq ft | 30 ft (25 on some streets) | 15 ft | 30 ft | 40% |
| RS-9 | 9,375 sq ft | 30 ft | 10 ft | 30 ft (20 min.) | 40% |
| RS-6 | 6,250 sq ft | 30 ft | 10 / 8 / 6 ft by lot width | 30 ft (20 min.) | 40% |
Older houses that already sit inside a setback are nonconforming, and enlarging them may need a variance from the Zoning Board of Appeals. We’ll tell you if that’s likely before design.

Additions That Fit Mount Kisco Houses
- Second story. The most efficient way to add bedrooms on a small lot, since it uses no extra coverage. An engineer checks the foundation first.
- Rear family room and kitchen. Opening the back of the house to the yard, kept inside the rear setback.
- Primary suite. A bedroom, bath and closet over an existing garage or one-story wing.
- Garage conversion. Turning attached garage space into living area, with the driveway and parking rules checked.
- Dormers. Usable rooms in an attic without a full second floor.
Our Addition Process
1. Zoning check
District, setbacks, coverage and any nonconformity.
2. Design
Architect drawings, sealed where the Village requires them.
3. Permits
Village Building Department, tree permit, and ARB only if the street façade changes.
4. Build
Foundation, framing and tie-in, then licensed trades and finishes under one project manager.
5. Close-out
Final inspections and a written warranty.
Mount Kisco Home Addition FAQs
How close to the property line can an addition be in Mount Kisco?
It depends on the district. In RS-12, side yards are 15 feet and the rear yard is 30 feet. In RS-9, side yards are 10 feet. In RS-6, the smallest one-family district, side yards step down from 10 to 8 to 6 feet depending on lot width. Front yards are generally 30 feet, or 25 feet on some shorter streets.
Is there a limit on how much of the lot we can cover?
Yes. The RS-6, RS-9 and RS-12 districts each cap development coverage at 40 percent of the lot, which counts more than just the house footprint. Driveways and patios matter, so we total everything before adding square footage.
Will a rear addition need ARB approval?
Usually not. For single-family homes, Mount Kisco’s Architectural Review Board reviews new houses and changes to the street façade. A rear or side addition that doesn’t change the façade typically stays with the Building Department, which makes the call case by case.
We have a big tree where the addition would go. What now?
Mount Kisco requires a tree removal permit, approved by the Village Naturalist, before regulated trees are removed. We include it in the permit plan and look at whether shifting the footprint saves the tree.
Related Pages
We also build additions in Bedford, Chappaqua and Pleasantville.
- Home additions & extensions
- Remodeling in Mount Kisco, NY
- General contractor in Mount Kisco, NY
- Custom home builder in Mount Kisco, NY
- Home additions in Bedford, NY
- Home additions in Chappaqua, NY
- Contact Guardian for a free estimate
- Roofing in Mount Kisco, NY
- Siding in Mount Kisco, NY
- Whole-Home Remodeling in Mount Kisco, NY
Need More Room in Mount Kisco?
Send us your address and what you’d like to add. We’ll check the setbacks and send a written estimate.
Guardian Remodeling Corp · 143 Lake Shore Dr W, Carmel, NY 10512 · 914-912-0385 · Frank@guardianremodelingcorp.com
