More concrete fails in Sonoma County from what happens beneath it and around it than from the concrete itself. Winter water, summer shrinkage and roots are the three things to plan for.
Do I need to worry about drainage?
Yes. Drainage is the first thing to settle on any concrete job here. Nearly all the year's rain arrives in a few winter months, and on clay it runs off instead of soaking in. A slab needs a slope of about one eighth to one quarter inch per foot, and the water needs somewhere to go: a lawn, a swale, a drain or the street gutter. Downspouts should discharge beyond the slab, not at its edge.
My patio or driveway slopes toward the house. How serious is that?
It is worth fixing. Concrete that slopes toward the house sends every storm against the foundation and, on clay, keeps the soil there swollen. Options run from a channel drain cut across the slab, to lifting the low side, to replacing the slab with the correct fall. Which one suits depends on how much slope is wrong and whether the slab is otherwise sound.
Can tree roots crack or lift concrete?
Yes. Tree roots grow thicker each year and lift whatever sits on them. In Santa Rosa the common culprits are street trees in the planter strip, valley oaks, redwoods and liquidambars. Roots also dry the clay around them in summer, which lets nearby slabs drop. Damage usually starts at a joint or an edge.
Can I fix the concrete and keep the tree?
Often you can keep the tree. Choices include bridging over roots with a thicker reinforced panel, curving the walk away from the trunk, using a shallower base in the root zone, or installing a root barrier along the new edge. Cutting large roots close to the trunk risks killing the tree or making it unstable, so an arborist should advise before any major root is cut. Santa Rosa regulates heritage trees and street trees, so check with the city first.
My neighbor's new concrete sends runoff onto my property. What can I do?
Start by showing the neighbor during a storm, since many people do not realize where their water goes. A small curb, a channel drain or a redirected downspout often solves it. In California a property owner who changes the natural flow of surface water is expected to act reasonably and can be liable for damage caused by runoff. If talking fails, the city or county can tell you whether a grading or drainage rule applies, and a lawyer can advise on your rights. This is general information, not legal advice.
Does clay or soft soil change the job?
Yes, it changes the base, the steel and the joints. Much of the Santa Rosa Plain and the valley floors toward Petaluma and Sonoma is clay with real shrink-swell movement. On it we dig deeper, place more compacted rock, reinforce the slab and space joints closer. Sandy loam west of Sebastopol behaves differently: it drains well but erodes at slab edges. For building foundations, a soils report sets the design.
My gravel driveway turns to mud every winter. Is concrete the answer?
Concrete is a lasting answer for the part of a gravel driveway you use most. The mud comes from rock being pushed down into wet clay. Some owners pave the parking area and the first stretch from the road and keep gravel elsewhere, with fabric under fresh rock to stop it sinking. Either way the water needs a ditch or culvert to follow, or it will cut under the new work.
My patio was poured over an old trench and now it has settled. Can it be fixed?
Usually. Soil put back into a trench for a sewer, water or gas line keeps compacting for years unless it was tamped in layers. A slab over it sinks in a line that follows the trench. If the slab is intact, lifting can fill the void and bring it level. If it has cracked along the trench, that strip is cut out, the fill is compacted properly and the strip is repoured.
I am in a flood-prone area. Should the patio or slab be raised?
In a mapped flood zone, the building rules decide floor heights, and the permit office will tell you what applies. Low ground near the Laguna de Santa Rosa, Santa Rosa Creek and the Russian River does flood in big storm years. Flatwork such as patios and drives can sit at grade, but it should not block or redirect flood flow, and fill is restricted in some zones. Raising a patio above the yard calls for edge walls and may need a permit. Ask before bringing in fill.
Do hillside lots need anything special?
Yes. On the slopes of the east side, water moving downhill has to be intercepted and carried around a slab, not under it. Slab edges on the downhill side need support so the base cannot wash out. Any cut into the slope for a patio or parking pad is likely to need a retaining wall, and taller walls need engineering and a permit.
The real number for your property comes from a free on-site estimate with measurements and a written quote. Call (707) 385-5837, or text a photo of the area.