Concrete sidewalk building in Atherton CA - a walk that stays level underfoot

A residential concrete sidewalk in San Francisco usually costs about $5 to $12 per square foot installed, which gives you a ballpark before anyone measures. Your own figure comes in writing after I walk the route, since the roots, any driveway crossing and the old walk coming out all change it.

Yes, if any of the work reaches the public right-of-way, the strip along the street, because Atherton requires an encroachment permit for any work there. The town's code also doesn't allow poured concrete in that strip except where it's the way in and out of the property, so that rule can decide where your walk stops. We check this before we quote, and when a permit's needed we handle the application and meet the inspector on site.

A Michigan concrete industry guide says a new sidewalk can be opened to traffic after 7 days of curing, or sooner if testing shows it's reached its strength. Curing is the slow hardening concrete does after the pour, and we start it right after finishing because a walk that dries out too fast ends up weaker. Plan cars and deliveries around that week, especially if the walk crosses your driveway.

They can, because roots growing under a walk can lift it over the years, so the best defense is a route that gives trees room. If you're planting new trees beside the walk, a North Carolina field study found that a root barrier, gravel and foam put in at planting went with minimal lifting or cracking. In Atherton, native oaks anywhere on the lot and larger trees in the town's tree preservation area count as heritage trees that must be protected during construction, with penalties for damage. The town's listed step for cutting roots over 2 inches is a letter from the site arborist that the Town Arborist reviews before work starts.

Start with the dug-out, packed base, shape the walk so water runs off it with no low spots and nothing heading toward the house, and cut control joints on time. Control joints are shallow grooves that give the concrete a place to crack in a straight line we chose, instead of wandering across the walk. Nobody can promise concrete won't crack at all, but those steps usually keep cracks small and where you expect them.

Ask how they'll keep the support even across utility lines and where the walk meets the driveway, since those transitions are where walks tend to settle unevenly. The state's concrete contractor license covers forming, pouring and finishing flat concrete, so that's the license to look for. If you're redoing the garage too, I can look at garage floor concrete on the same visit.