Riverside Concrete Pro pours slab foundations to engineered drawings, over a vapor barrier and a base built to what the soils report found, with the reinforcement signed off before concrete is ordered.
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Structural work, not flatwork
A slab foundation is part of the building, not a surface laid on the ground. It carries the walls, the roof and everything the structure will ever hold, and the soil it is cast on decides whether it stays flat for the life of the house. So the job starts with a soils report and a stamped set of drawings rather than with a tape measure and a form board.
Marco Delgado started Riverside Concrete Pro in 2021, after 15 years on Inland Empire crews, and he is on site for the steel and the pour on every foundation. Most slabs booked here now are for accessory dwelling units, which California has spent several years making simpler to permit, and a detached ADU in a back garden is a foundation before it is anything else.
Because it is structural, a foundation is drawn, plan-checked and inspected in a way no patio slab ever is. The set goes to Building & Safety at the City of Riverside, an inspector passes the reinforcement before the pour and the slab again afterward, and the build runs under a CSLB C-8 concrete license with liability insurance on every job. Every slab we pour carries a written workmanship guarantee against defects in how it was built.
Warning signs
A door that stops latching and a window that binds in one corner are the frame reporting that the slab beneath it has moved. Planing the door hides that for a season. What moved is the ground, and until the cause under the concrete is found the same door sticks again next winter.
Hairlines from curing turn up in every slab and mean nothing. A crack wide enough to take a coin, running through the floor covering with one side higher than the other, is structural. Measured on two visits a month apart, it either holds still or the ground is still opening it.
Marbles running to one wall is the old test and it still works. More than an inch of fall across twenty feet is past what any floor finish will disguise, and on the arroyo clays it tends to lift in a wet January and drop again by August rather than settle once and stop.
A habitable slab cast with no sheeting under it draws ground moisture up through the concrete for as long as the building stands. Vinyl lifts at the seams, adhesive lets go and the room carries the smell. Nothing applied to the finished floor answers it: the water arrives from below.
What's included
Standard on every foundation, with no add-ons. The order below is the order an inspector sees it in, because a slab is signed off in stages and each stage is a chance to prove what is underneath before it disappears.
The report for your lot sets the design, and where no current one exists we have it done before a line is drawn.
A set sized by an engineer to your soil and your building, submitted for plan check rather than sketched onto the estimate.
Soft material is taken out to firm soil, or rebuilt as engineered fill placed in lifts and tested before the base goes on.
Compacted base, then a 10-mil sheet lapped and taped under anything habitable, so moisture cannot rise into the finished room.
Bar sized, spaced and lapped exactly as drawn, chaired up off the barrier so it sits inside the concrete rather than under it.
The perimeter deepened where the walls will land, poured in one go with the field so there is no cold joint at the edge.
We meet the inspector for the pre-pour reinforcement check and again for the slab, and the card is signed before framing begins.
Kept damp a full week, the site swept back to the fence, and the written guarantee handed over with the signed card.
Your options
Four ways to found a building on Riverside ground, judged on the soil each one suits, how much engineering it takes, what it does when clay underneath starts to move, and how long the crew is on site before a framer can start.
| Option | Ground it suits | Engineering | If clay moves | Time to framing |
|---|---|---|---|---|
| Conventional slab | Sandy loam, river sand, decomposed granite | Standard details off one soils report | Follows the ground and can crack | 5 to 8 days, then 7 to cure |
| Post-tension slab | Arroyo clay over an expansion index of 20 | Designed and stressed by a specialist | Rides the movement as one plate | 7 to 10 days, then 7 to cure |
| Stiffened raft slab | Mixed ground and cut-and-fill benches | Deeper beams drawn to the report | Beams span the soft pockets | 7 to 10 days, then 7 to cure |
| Raised wood floor | Steep lots a slab would need fill on | Footings and stem walls, no slab design | Least affected, floor sits clear of it | 10 to 14 days, framing follows on |
A conventional slab asks least of the engineer, post-tension is the most forgiving on clay, and a raised floor is the easiest to reach pipework under afterward.
Local knowledge
Two things set the design here before a line is drawn: what the soil does once it takes water, and what somebody buried on the lot before anyone thought of building on it.
Riverside grew outward from an 1870s townsite, so an infill lot on the Eastside or behind a Wood Streets bungalow can sit on a century of buried trench, demolished footings and imported dirt. None of that counts as ground to found on. It comes out to firm soil, or it is replaced with engineered fill placed in lifts and tested as it goes, because a slab bridging a soft pocket will break over it whatever strength the concrete was ordered at.
The soil then chooses the slab. Where the Web Soil Survey sheet and the trench agree on decomposed granite or sandy loam, a conventional slab with thickened edges carries the building. In the arroyo clays, an expansion index over 20 pushes the design to post-tension or a stiffened raft, and that call belongs to the engineer whose stamp goes on the drawing rather than to the crew pouring it.
Our process
A foundation runs from the soils report to the inspector closing out the pour. One crew, one written figure, and the plan check submitted by us before anything on the lot is dug.
Marco Delgado sets out the footprint, checks whether a pump can reach it, and finds out what soils work the lot already has on file.
An engineer sizes the slab to that report and the stamped set goes to Building & Safety, where the plan check decides the start date.
Soft material is removed to firm soil or rebuilt as engineered fill, then base is compacted and the vapor barrier laid and taped.
Bar is tied and chaired to the approved drawing, and the pre-pour reinforcement inspection is passed before a truck is ordered.
Concrete is placed and screeded flat, kept damp a week, the site cleared, and the final inspection closed out in front of you.
What moves the estimate
The footprint sets the floor and the ground sets the rest. What moves it after that is how much engineering the soil asks for, and how much of what is on the lot today has to leave before anything can be cast.
Between about 400 and 1,200 square feet, and the number turns on whether a pump reaches the back or the concrete is barrowed.
Joining a new slab to a 1920s bungalow means matching the finished floor height and cutting the old footing back to sound material.
A slab taking a vehicle or a machine is deeper at the edges and carries more steel than the same footprint would as a room.
Post-tension design, deeper beams or a full engineered fill are set by the soils report, not by how large the building above is.
The figure is written at the property once the footprint has been walked, and we call back within 1 business day to arrange that visit. (951) 584-0685 or send us a message.
Send the form and we call back within 1 business day to book a time. We walk the footprint, tell you what the plan check is going to want, and leave a written figure with you. Nothing is owed if you take it no further.
Reviews
Three reviews of foundation work here, left on Google, Facebook and the BBB. Each is about a slab cast for a building rather than about flatwork out at the frontage.
“We wanted the ADU on the old garage slab and assumed that was that. Marco had it cored, showed us 3 inches with no steel in it anywhere, and poured a new one to the drawing instead. Our framer was standing on it 9 days after the dig started.”
“Our Eastside lot turned out to have a foot of old trench fill in it that nobody had mentioned. They dug it out to solid ground, brought fill back in in layers and had it tested. The steel passed first time and we never saw a change order.”
“Clay ground, so the engineer called for post-tension. They laid the sheeting, set the cables and had the inspector out before anything was placed. Two winters later the doors in the new room still shut the way they did the week we moved in.”
FAQ
What people want settled before they commit to a foundation: what moves the figure, how long the permit takes, what goes in under the concrete, and who stands in front of the inspector.
Three things: the footprint, what the soils report asks the engineer to draw, and how much unsuitable ground has to leave the lot before anything is cast. A building on decomposed granite with standard details is one job; the same one over arroyo clay above an expansion index of 20 is drawn as post-tension, which adds to the design as well as the pour. The figure comes from the visit, in writing.
Plan check is the long part, not the concrete. Engineering and the permit through Building & Safety usually run several weeks before a shovel moves. The dig, the fill, the base, the steel and the pour then take 5 to 10 days depending on the design, with 7 days of curing before a framer stands on it and 28 days before the slab is at full strength.
For anything habitable, yes, unless a current report already covers the lot. It tells the engineer what the ground does when it takes water, and the expansion index in it is what chooses between a conventional slab, a stiffened raft and post-tension. Without one the design is guesswork, and a plan checker sends the set back rather than approving it.
Always, because a foundation is structural. It takes stamped drawings, a plan check and a permit from Building & Safety at the City of Riverside, an inspection of the reinforcement before the pour, and a further one on the slab afterward. We submit the set, meet the inspector at both stages and hand you the signed card at the end.
Rarely, and never on the assumption. Garage slabs around Riverside were mostly poured 3 to 4 inches thick with no steel, no sheeting and no thickened edge under a wall line, and a habitable building cannot be framed on that. We core it and hand the results to the engineer. Where it will not carry, it comes out and a new slab goes down on the same footprint.
Yes, in writing, and it is handed over with the signed inspection card. The written workmanship guarantee against defects in how it was built covers the fill and its compaction, the sheeting, the placing of the steel, the thickness and the finished level, with the terms on the estimate you sign. Ground movement past what the engineer designed for sits outside it, as does anything cut or altered after we leave.
A mix specified by the engineer rather than chosen by us, typically 2,500 to 4,000 psi from a Riverside County batch plant, with bar size, spacing and lap length all drawn. Under it sit compacted Class 2 base and a 10-mil sheet. A post-tension design adds sheathed strand, stressed a few days after the pour. Every one of those is on the approved set and checked against it.
No, though you should be there for the footprint walk at the start and the hand-over at the end. Before the dig we need the gate, the water meter and any easement pointed out, and clear standing for the pump or the trucks. On pour day the frontage is taken for a few hours, and the finished slab is off limits to feet and pets for 24 hours.
Service area
The eight towns nearest our Chicago Avenue yard, with the distance from Riverside beside each. Coverage reaches 20 towns inside 25 miles, and each of them plan-checks a foundation at its own counter.
Four jobs that sit either side of a foundation: the ground that has to be held before it can be set out, and the concrete that goes down once the building standing on it is framed.
Pads and perimeter footings where the drawing calls for them under a slab.
Where a level pad has to be cut into a slope before the slab is set out.
The garage floor beside a new ADU, poured thicker and jointed on a grid.
Access to a building at the back, poured once the framing above is done.
Call or send the form and we come and look at the lot, the access and whatever soils work you already hold. The visit and the written estimate cost nothing, and there is nothing to pay unless you decide to build.