Commercial Site Flatwork & Paving

A parking lot never fails where the cars park. It fails at the trash enclosure, at the loading door, on the two turns the delivery truck makes every Tuesday, and down the drive aisle the fire lane runs along. Those spots carry the real axle load, and they decide what a property spends on paving over twenty years.

We build commercial flatwork across the Front Range: lots, access roads, loading aprons, sidewalks, and the tie-ins between them. Most of a scoping conversation is about load spectrum and access, not finish. Tell us the heaviest vehicle that visits on a schedule and how many hours a day the site has to keep trading, and most of the design falls out of those two answers.

Design to the heaviest recurring vehicle, not the average one

Passenger cars are close to irrelevant structurally. A loaded refuse truck lifting a container, or a tractor dropping trailer landing gear on a bare slab, applies more load through a few square inches than a parking bay sees in a year. So the section gets zoned. Thin where cars sit, thick where trucks turn, thickest at the pad the container lands on.

Joint layout follows the same logic. Sawcut on the day of the pour at spacing matched to the section, and keep joints out of the primary wheel path where geometry allows, because a joint under repeated forklift or steer-axle traffic is where spalling starts. At construction joints in truck areas we dowel, so adjacent panels deflect together instead of stepping apart. Reinforcement is #4 bar on chairs at roughly a 24 inch grid anywhere trucks run. Mesh is fine under cars, and fiber replaces neither.

Section by traffic zone

The sub-base and the water are the whole job

Concrete pavement is only as good as what it sits on. We proof-roll the subgrade before base goes down, because a soft spot found under a loaded tire costs a morning and the same spot found after the pour costs a panel. Aggregate base goes in compacted lifts, thicker under the heavy zones. On expansive clay, which is most of this metro, the answer is sometimes moisture conditioning, sometimes removal and replacement, sometimes separation fabric over soft subgrade. The geotech report tells us which.

Then drainage, where lots go wrong quietly. Every square foot has to shed to an inlet. We want positive fall everywhere rather than a flat plane that ponds at the joints and works freeze and thaw into them all winter.

Accessibility complicates that. Accessible routes and stalls cap cross slope at 1:48, ramp runs at 1:12, with 36 inch clear width, 60 inch landings, and detectable warnings at curb ramps. Drainage wants slope and accessibility limits it, so the grading plan solves both at once instead of picking a winner.

Concrete against asphalt on a twenty year view

Phasing a lot that has to keep operating

The number that governs a phasing plan is seven days, because that's how long a new pour waits before cars roll on it. Not one day, not a weekend. So a phase is offline about a week, and the sequence gets drawn around stall counts, the accessible route to each entrance, and a fire lane that stays open throughout. Confirm that last one with the authority having jurisdiction before the schedule locks.

We normally break a lot into quarters or thirds, sawcutting the phase boundary on a panel line and dowelling the cold joint so the next phase ties in structurally rather than butting against it.

Night and weekend placements come up constantly on retail and medical sites. Weekends usually beat nights. A night pour in shoulder season means heated water, non-chloride accelerator, blankets, and finishers under temporary light. All of it doable, all of it more expensive. And we won't place on frozen ground at any hour.

What we want in the bid package

• Geotechnical report, or written permission to price against an assumed subgrade
• Vehicle mix, including the heaviest unit that visits on a regular schedule
• Hours the property must stay open and any noise restrictions in effect
• Inlet, utility, and light pole base locations, and who owns adjustment of each
• Whether existing section is removed full depth or overlaid
• Accessible route from stalls to each entrance, and who is certifying it
• Line items you want priced as adds and deducts by the unit

Coordination is most of the schedule risk

Concrete rarely sits alone in a site package. Striping follows us and needs clean, dry, cured surface, so that subcontractor's window is set by our pour dates rather than the other way around. Anything cast in gets confirmed before placement: light pole bases, bollard sleeves, EV conduit, irrigation sleeves under drive aisles. Coring a finished 8 inch slab to fix a missed sleeve is an expensive lesson.

Traffic control is scope, not an afterthought. Signage, cones, flaggers where trucks cross a live aisle, and a marked pedestrian route that stays accessible while the permanent one is closed. Then barricade the fresh pour harder than seems necessary. Somebody always drives on it.

The phasing plan gets written twice. Once on paper, and once the first morning, when we find out where the delivery drivers actually go instead of where the site plan says they go.

Site superintendent, commercial flatwork