Matanuska-Susitna Borough, AK Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Matanuska-Susitna Borough, AK, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Accessory footprint cap
- 150% of principal dwelling
- Minimum dwelling size
- 500 sq ft on one floor
- Setback source
- MSB Chapter 17.55 (via § 17.75.160)
- Applies to
- 3 designated SFR Land Use Districts only
- Governing sections
- §§ 17.75.060(B)(1), 17.75.150(B)
Summary
A shed, detached garage, barn or other storage building in the borough's Single-Family Residential Land Use Districts, Canoe Lake Subdivision, Chugach View Estates and Wilderness East Subdivision, is a permitted accessory use, but all accessory structures combined cannot exceed 150 percent of the principal dwelling's square footage under §§ 17.75.060(B)(1) and 17.75.150(B). Setbacks follow MSB Chapter 17.55.
Noncommercial garages attached or detached, storage buildings, barns, fences, and other incidental structures and uses, the total square footage of which all accessory uses shall not exceed 150 percent of the principal dwelling; ... Accessory building uses, whether attached or detached to the principal dwelling, must not have a larger footprint than 150 percent of the principal dwelling.
Full Breakdown
Section 17.75.060(B)(1) lists noncommercial garages, storage buildings, barns, fences and other incidental structures as permitted accessory uses within the borough's Single-Family Residential (SFR) Land Use District, established under Chapter 17.75 and currently reaching only Canoe Lake Subdivision, Chugach View Estates and Wilderness East Subdivision per § 17.75.035, not the borough at large. The chapter caps the combined square footage of every accessory structure on the lot, sheds, garages, barns and the rest, at 150 percent of the principal dwelling's footprint, a figure repeated in § 17.75.150(B)'s building size standard.
Section 17.75.150(A) separately requires the principal dwelling to have at least 500 square feet of living area on one floor before any accessory structure is measured against it. Placement of a shed or other accessory building is governed by the setback requirements of MSB Chapter 17.55, incorporated by reference through § 17.75.160, rather than by a standalone setback distance inside Chapter 17.75 itself. Accessory uses and structures must also serve a principal structure on the same, an adjacent, or a contiguous lot under common ownership, and be clearly secondary and incidental to the single-family dwelling.
Violations & Fines
An accessory building that pushes the combined accessory footprint over 150 percent of the principal dwelling, or that is not clearly secondary and incidental to the home, violates §§ 17.75.060(B)(1) and 17.75.150(B) and the conformance requirement in § 17.75.040. Under § 17.75.190, this is a borough infraction, enforced under MSB Chapter 1.45 with a fine capped at $1,000 by § 1.45.080(A).
Frequently Asked Questions
How big can a shed be on a lot in one of Mat-Su's SFR districts?
Does this 150 percent accessory cap apply everywhere in the borough?
What setback applies to a shed in these districts?
Sources & Official References
Other rules in Matanuska-Susitna Borough
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