More Bay Area concrete patio problems are caused by poor drainage design than by poor concrete quality.
Questions to ask before the pour
- Where does surface water go when it rains — does the patio slope away from the house?
- Is there a defined drainage endpoint — a planting area, a drain inlet, a channel, or a connection to the street?
- What is the minimum slope specified? (1/8 inch per foot minimum toward a drainage point is standard.)
- If the patio connects to the house at a door or sliding threshold, how does drainage work at that transition?
- If a drain inlet is included, what size, and does it connect to the existing drainage system?
Why drainage is a form layout decision, not a pour day decision
Concrete drainage slope is built into the formwork before the pour. Once the concrete is placed and finished, the slope is fixed. There is no way to re-slope a concrete patio after it cures without removing and replacing it.
Related: Concrete Patios · Pricing · Repair vs. Replacement · FAQ