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Home My WebLink About2026/03/06 - Justification Letter - 200 Bridle Path 200 Bridle Path THE HEFFERNANs North Andover, MA 01845 603-475-4694 rheffernan@gmail.com alyssa.small@gmail.com Justification Letter—ADU Addition with the Rear Stair Location 6 MARCH 2026 Property Address: 200 Bridle Path Applicant: Alyssa and Ryan Heffernan Amy Maxner, Administrator Project: Accessory Dwelling Unit Above Existing Garage Town of North Andover Subject: Justification for Locating Stairs and Deck at Rear of Garage Conservation Commission within the Watershed Protection District (Article 22) 120 Main Street North Andover, MA 01845 This letter provides a formal justification for locating the proposed stairs and small deck for the accessory dwelling unit (ADU) at 200 Bridle Path at the rear of the existing garage. The property lies within the Watershed Protection District, regulated under Article 22 of the Town Bylaw. We have evaluated all feasible alternatives in accordance with the Bylaw's purposes of protecting groundwater recharge, minimizing land disturbance, and preventing unnecessary alteration of natural hydrology. Based on this analysis and the architectural plans submitted, the rear stair location is the least environmentally impactFul practicable alternative and best satisfies both the Bylaw and the ADU's accessibility requirements. Alignment with Article 22—Watershed Protection District Article 22 emphasizes: • Minimizing soil disturbance; • Protecting natural infiltration; • Avoiding unnecessary expansion of impervious surfaces; and • Keeping development within already-disturbed areas whenever possible. The proposed rear stair location directly supports these objectives by: • Using an area that is already disturbed (gravel pad, AC equipment, maintained lawn); • Avoiding excavation for a full foundation; • Maintaining permeable ground beneath the structure; and • Preventing lateral expansion of the building footprint into undisturbed soils. PA G E �- uuuw MEF2G EFOF2 M AT Z Existing Site Conditions (Supported by Plans) The architectural plans clearly show: • The rear of the garage consists of a gravel pad and maintained lawn; • This area is already functionally disturbed and contains mechanical equipment; • No natural vegetation or undisturbed soils will be removed; and • The ADU itself is intentionally designed to be built above the existing garage and driveway, so as to mostly avoid new ground disturbance. In contrast, the side of the garage is tightly constrained and bordered by undisturbed soil. The plans demonstrate that placing stairs there would require: • A full foundation; • Excavation into undisturbed ground; • A wider footprint to meet stair geometry; and • Structural modifications that increase disturbance. The plans visually confirm that the rear location results in substantially less environmental impact. Impervious Surface Clarification Per the project architect: • The rear stair structure will technically increase impervious surface area because the space is currently open; however, the amount of additional impervious surface is approximately the same whether the stairs are located at the rear or on the side. Given this, impervious area should not be a distinguishing factor between the alternatives. Since both options create similar impervious area, we suggest the Commission's focus should appropriately shift to: • Soil disturbance; • Extent of excavation; • Impact on undisturbed areas; • Compliance with ADU design preferences; and • Accessibility and safety. Based on these criteria, the rear location of the ADU's stairs is overwhelmingly preferable. PA G E �— uuuuw I\/I E F2 4-- Ea F=C::)FRZ M AT Z Environmental Impact Analysis Minimal Soil Disturbance The rear stair structure will be built on posts (sonotubes or helical piles), requiring only small footings. Doing so avoids: • The need for excavation; • The need for soil removal; • The need for grading or fill; and • Disruption of natural hydrology. Preservation of Natural Infiltration Because the structure is elevated, the ground beneath remains permeable, supporting groundwater recharge consistent with Article 22. Avoidance of Lateral Expansion A side stair location would require: • A larger foundation; • Significant excavation; and • Expansion of the building footprint into previously undisturbed soil. This would create substantially greater environmental impact. Compliance with ADU Bylaw Design Preferences The ADU Bylaw expresses a preference that exterior stairs not be visible from the street. • A rear stair location naturally satisfies this requirement. • A side stair would be more visible and less consistent with the AUDU Bylaw's architectural intent. This important regulatory alignment favors the rear stair location. Accessibility and Aging-in-Place Considerations The ADU is being built as the homeowners' mother's/mother-in-law's forever home, and accessibility is a central design requirement. The rear location allows: • A shared mudroom with laundry; • Direct access to the first floor of the main house; • Safe access for a young child visiting the ADU; and PA G E �— uuuuw I\/I E F2 4-- Ea F=C::)FRZ M AT Z • Integration with the planned elevator, eliminating the future need for stairs for daily living use. These essential programming needs cannot be met with a side stair location, and the alternative would require significantly more disturbance to the resource area. Practicable Alternatives Analysis Alternative A:Side-Mounted Stairs (Rejected) • Requires excavation and a full foundation; • Disturbs undisturbed soil; • Expands the footprint into natural areas; • More visible from the street; • Fails accessibility needs; and • Demonstrated on plans to require significantly more disturbance. Alternative B: Rear-Mounted Stairs (Preferred) • Uses already-disturbed land; • Requires only posts with minimal soil disturbance; • Maintains existing drainage and infiltration; • Meets ADU Bylaw design preference; • Supports aging-in-place; and • Clearly shown on plans to be the least impactful practicable alternative. In conclusion, the proposed rear location for the ADU stairs and deck: • Minimizes environmental impact; • Avoids excavation and unnecessary disturbance; • Uses already-disturbed land; • Maintains natural infiltration and hydrology; • Aligns with Article 22's purpose and requirements; • Complies with the ADU Bylaw's architectural preferences; • Supports essential accessibility and safety needs; and • Is clearly supported by the architectural plans as the least impactful alternative. For these reasons, we respectfully request approval for the ADU's rear stair location as the most environmentally responsible and practical option within the Watershed Protection District. Regards, Alyssa and Ryan Heffernan PA G E �— uuuuw I\/I E F2 4-- Ea F=O F?, 1\/1 AT Z