All districts
An accessory structure is allowed only on a lot that has a principal building, and never in the front yard of that building (Section 3.02).
- On R-1 and R-2 lots with one- to four-unit dwellings: side and rear setbacks of 5 feet, or 3 feet with fire-rated construction. Maximum height 20 feet. At least 10 feet from any other structure.
- Structures of 200 square feet or less keep the same 5-foot setbacks with a lower height cap of 15 feet.
- On all other lots: 10 feet setbacks and 20 feet height.
Ferndale sets no cap on the total square footage of accessory structures. That is a verified absence, not an omission in this summary: the 200 square foot threshold only lowers the height limit, and no size ceiling appears in Section 3.02. Accessory dwellings are regulated separately under Section 5.01.
Projections are governed by Section 3.03: porches and decks may extend up to 50 percent into the front setback and within 3 feet of side and rear lines; pools and game courts are barred from front yards and need 5-foot side and rear setbacks; permanent equipment stays out of front yards.