Concrete Slabs in Rialto, CA

What we mean by a slab

On this page, a slab is a stand-alone piece of flat concrete that carries something other than cars. Driveways and patios have their own pages because they come with their own design questions. Structural slabs that carry walls and a roof, like an addition, a garage or an ADU, are foundation work with engineered plans and city inspections. Everything in between lands here: shed pads, spa pads, pool and AC equipment pads, trash and side yard strips and dog runs,.

These jobs look small, and that is why they get done badly. Plenty of Rialto sheds sit on a few pavers or a thin skim of bagged concrete. Within a couple of years the shed racks, the doors stop closing, and termites have found the wood floor.

Built for the ground under Rialto

Much of the city sits on sandy, gravelly ground that came down the Lytle Creek wash from the San Gabriels. It drains fast, which is good, but it is loose. Pour on it without compaction and the slab settles unevenly, usually at the corners first. We cut out the top layer, water and compact the native soil, then bring in base rock and compact it in lifts. That base is what keeps a loaded shed floor level for years.

Wind is the other local factor. When the Santa Anas come through the Cajon Pass in the fall and winter, anything light gets moved around. Sheds, playhouses and spa covers need to be anchored, so we set anchor bolts or straps in the wet concrete wherever the item you are putting on it calls for them.

Common slabs and how we size them

• Shed pads. We make the slab a few inches larger than the shed footprint so water drips off the roof onto concrete, not into a hole along the wall. A thickened edge helps on bigger sheds.
• Spa pads. A filled hot tub can weigh several thousand pounds. We pour these thicker with steel, set them dead level, and run a sleeve for the electrical before the pour so the electrician does not have to trench across a finished slab.
• Pool and AC equipment pads. Pumps, filters, heaters and condensers need a flat, stable base that sits above the dirt so rain and sprinkler water do not pool under them.
• Side yard and trash pads. A strip of concrete from the gate to the street-side corner ends the mud and weeds and gives the bins a level spot. We slope it so water heads to the yard or the street, not toward the house.

How a slab job runs

First visit, we measure, check access and ask what is going on the slab, since that decides the thickness and whether it needs rebar or wire mesh. Most of the time we can pour four inches. Spa pads and anything with a heavy load go thicker. We call in a utility locate before digging, because older Rialto lots often have buried sprinkler lines and gas lines running to a back yard barbecue or a pool heater.

Then we dig out, compact, set forms and steel, and pour. We cut control joints so the cracks we know will happen land in straight lines. On a summer pour, when afternoon highs run past 100, we start early in the morning, keep the slab damp while it cures and avoid finishing in direct midday sun, because hot dry air pulls water out of the surface and leaves it weak and dusty.

You can usually walk on a slab the next day. Hold off on setting a shed or a filled spa on it for about a week, and longer for anything heavy.

What changes the price

The size of the slab sets the base cost. After that, it comes down to access and prep. A slab in a back corner of a lot behind a narrow gate means hauling concrete by wheelbarrow or bringing in a pump. Old concrete or a cracked patio that has to be broken out and hauled off adds labor and dump fees. Thicker slabs, steel, anchor bolts and electrical sleeves add material. If you would like the slab to match the look of a nearby patio, ask about stamped finishes or simple color.

Questions about concrete slabs

Do I need a permit for a slab?

A plain slab on the ground usually does not, but what goes on it may. A large shed, a covered structure or a spa with new wiring can trigger a permit. Check with the City of Rialto building division before the pour. We will point out anything we expect to need one.

Can you pour over my old cracked slab?

Sometimes a thin overlay works on a slab that is cracked but still level. If it has sunk or broken into pieces, pouring over it just copies the problem. In that case we break it out. For cracks in a slab that is still sound, see our concrete repair page.