Fence or deck costs in San Francisco

Planning a deck in San Francisco? Start with the 30-inch line. San Francisco Planning says a new deck on an existing building needs a building permit with plans if any part of the walking surface is more than 30 inches above grade. Roof decks need one too.

Replacing an old deck is not automatically simple. Many decks that were built legally now poke into required yards, usually because the yard rules changed after they went up. Planning tells owners not to assume a deck can be rebuilt in-kind. A deck three feet or less above grade, though, is allowed anywhere in the required rear yard.

Some decks also trigger notice to the neighbors. A deck held up only by the wall it hangs from is exempt from notification. So is a deck on posts that stays no more than 10 feet above grade inside the buildable area of the lot.

Fences have their own handout. You don't need a building permit for a fence three feet or less at the front, or six feet or less at the side or rear lines. Inside a required front setback, a solid fence stops at three feet. It can go to six only if it's 75 percent open, like wrought iron. A picket fence won't count unless the slats are very thin or the gaps are wide. In the required rear yard, a fence can reach ten feet.