Decks
See the Deck Handout (PDF).
A permit is required for installing a new deck, replacing an existing deck and replacing deck boards. If you have questions, please call 651-638-2050.
Information required for permit:
- Site Plan
- Beam size
- Number of posts and size
- Post spacing
- Joist length, size and spacing
- Joist cantilever length
- Decking material type
- Height above grade
Frost Footing / Foundations
Required for any deck attached to a dwelling, porch or garage that has frost footings. The minimum depth to the base of the footing is 42 inches. Approved pin foundations are acceptable. Pin foundations are not permitted to support screen porches, 3-season porches or other attached habitable spaces.
Total Load
All decks shall be designed to support a live load of 50 pounds per square foot (40 pounds live load plus 10 pounds dead load).
Guards / Guardrails
Required on all decks or stairs more than 30 inches above grade. Required guards shall be a minimum 36 inches in height and shall not have opening from the walking surface to the required guard height which allows passage of a sphere 4 inches in diameter. Exception: On an open stairway, the triangular opening formed by the riser, tread and bottom element of a guardrail must be sized so that a six-inch sphere cannot pass through.
The top rail must support a 200-pound lateral load. Infill area must withstand a horizontally applied normal load of 50 pounds on an area equal to one square foot.
Handrails
The top shall be placed not less than 34 inches or more than 38 inches above the nosing of the treads. Stairways having four or more risers shall have at least one handrail with handrail ends returned or terminated in posts. Circular hand grips shall be between 1 1/4 inches to 2 inches in cross-sectional dimension or the shape shall provide an equivalent gripping surface.
Cantilevers: Overhanging Joists & Beams
Beams shall not overhang support posts by more than one foot unless a special design is approved.
Framing Details
Header beams and joists that frame into ledgers or beams shall be supported by approved framing anchors such as joist hangers.
Flashing
All connections between deck and dwelling shall be weatherproofed. Cuts in exterior finish shall be flashed.
Nails & Screws
Use only stainless steel, high-strength aluminum or hot-dipped galvanized.
Wood Required
All exposed wood is required to be approved wood with natural resistance to decay (redwood, cedar, etc.) or approved treated wood. This includes posts, beams, joists, decking and railings. Any composite or plastic decking materials must be approved by Building and Inspection prior to installation.
Stairs
Minimum width is 36 inches. Maximum rise is 7 3/4 inches, minimum rise is 4 inches. Minimum run is 10 inches. Largest tread width or riser height shall not exceed the smallest by more than 3/8 inch. Maximum 4-inch opening at risers greater than 30 inches above grade.
Illumination
All exterior stairways shall be illuminated at the landing to the stairway. Illumination shall be controlled from inside the dwelling or automatically activated.