Some projects forgive mistakes. Carports do not.

One wrong assumption about soil, one structural detail overlooked, one steel price swing between bid and build, one buried obstruction nobody flagged or knew about, and any one of those can wipe out a project’s margin. Together they can sink a company. Carports are one of the fastest growing and most misunderstood segments of commercial solar. Schools, hospitals, manufacturers, and municipalities all want covered parking that also generates power, and researchers peg the carport segment’s growth in the low double digits, outpacing a commercial market that set records in 2025 and that SEIA and Wood Mackenzie expect to grow about 12% a year from 2027 through 2030. The raw material is everywhere: surface parking covers more than 5% of all US urban land, a footprint larger than Rhode Island and Delaware combined, almost none of it earning its keep beyond storing cars. The opportunity is enormous, but only for EPCs and developers who understand how these projects behave.

That was the through-line of a recent Clean Power Hour panel I hosted with three people who build carports for a living: Kyle Sinclair, CEO of Sinclair Designs and Engineering (SDE); James Strizki of GenMounts; and Matt Boyce, principal engineer at Engineered Solutions and a licensed PE in 27 states. In a live poll, 58% of attendees had completed fewer than two carport projects. Sinclair’s warning: residential and rooftop installers are walking into a segment that is the opposite of high-volume, cookie-cutter work. A typical carport runs about half a megawatt, stands 25 feet tall, and swallows 100 cubic yards of concrete, roughly ten truckloads. This is heavy construction wearing a solar hat.

De-risk the design by buying engineering early

The cheapest insurance on a carport is preliminary engineering before the bid goes out. “The EPCs that win the most have actually spent a little money for preliminary engineering, so they can provide an accurate bid based on validated information,” Sinclair said. At a roughly 30% close rate, that upfront spend gets recouped across the projects that move forward. SDE runs a four-step workflow with its partners: a geotechnical study and preliminary foundation engineering, a finite element analysis against site-specific building codes, a full internal design review, then manufacturing and deployment.

Not everyone buys that logic cleanly. John Weaver, the Massachusetts developer and general contractor known as the Commercial Solar Guy and a pv magazine USA contributing editor, has built these projects and pushes back on the economics. “You can’t do engineering on all your sales proposals. Real engineering is expensive,” he said, and at those close rates, pre-quoting every bid with paid engineering does not pencil out. His reframe flips the sequence: the moment a customer funds engineering, the deal is effectively closed. “Putting real money at stake is the same as signing,” Weaver said. “If they’re putting down real money for engineering, you’ve crossed a precipice of trust with a client.” His workaround is to break out the foundation as its own line item with a range, then convert the buyer with a small paid study: “You can drop your cost 5% by spending 15,000 dollars today and doing geotech and ground-penetrating radar. That’s a buy signal.”

The recurring villain is the ground. “The foundation is usually 99.9% of the time the hardest part of the project,” Strizki said. He has hit four-foot brick voids from old heating ducts, demolished parking garages, and six feet of uncompacted fill that looked like flawless blacktop from the surface. Boyce, who reviews projects independently, will not design without a geotech and warns that the most dangerous phrase on any site is the longtime caretaker insisting nothing was ever built there. Free intelligence beats expensive surprises: 811 locate calls for public utilities, existing geotech reports (which exist about 90% of the time, since the host building has one), web soil surveys, and a phone call to local drillers who know the subsurface.

Price the variability, not the average

Foundations are where bids quietly bleed. Sinclair gave the math directly: drilling Michigan clay with no obstructions runs about $800 per hole, but hitting hard shale at four to six feet can push that to $2,500 once crews switch to rock drilling. On a half-megawatt site, that single variable can add $60,000, a 12 cent per watt swing. That is why carports commonly land at two to three times the price per watt of rooftop, and why the deal often dies on affordability rather than engineering.

The discipline is pricing the worst case with visibility, then carrying real contingency against it. Strizki described two customer types. Some demand a single all-in number and will not reopen it, forcing the contractor to bury enough contingency to absorb collapsing holes, temporary casings, and hydrovac work without a change order. Others value-engineer and agree to share the headache of a rough foundation transparently. Both can work. What fails is discovering the overrun after crews are mobilized, with subcontractors standing idle at prevailing wage while the budget compounds.

Weaver adds a blunter coda. Carports, he argues, are simply a higher-priced market than rooftop, and the contingency reflects it. “The contingency runs a higher percentage than on a rooftop, because there’s just less risk on a roof,” he said. And the buffer rarely comes back: “It’s not like the contingency always gets paid back, because customers don’t trust it. Those numbers end up staying in the projects, because everybody has to cover themselves.” The harder cost is the customer you never see: some prospects end the conversation the moment they hear the word risk attached to construction, which quietly selects for the buyers who can stomach it.

Steel, by contrast, is the controllable line item. SDE locks a fixed rate with a material deposit and typically stocks raw material for projects under two megawatts, insulating EPCs from mill lead times. Domestic, vertically integrated manufacturing matters here: it removes the import lead-time risk that has burned the residential supply chain and keeps Plan B and Plan C foundation cages moving to the site without breaking the install sequence.

De-risk construction by respecting the craft

Carports punish corner-cutting on a delay. Boyce’s caution: new entrants tend to be light on every input, sending six people when the job needs eight, a backhoe when it needs a large material handler. Bad concrete loads and mis-set anchor bolt templates are routine, and failures rarely show on day one. Improperly drilled or backfilled foundations surface a year or two later as consolidation, undermined parking lots, and conduit added after the fact.

Strizki’s single highest-value tip costs almost nothing: walk the site with a skeleton crew a week before drilling and do an informal layout, because curb lines, storm sewers, and stepped lots that never made the drawings appear nearly every time. Start slow, then go.

Weaver’s warning is that the ground is not the only place margin leaks. Assembly methods carry hidden cost too. On a recent job he was handed a racking product that required through-bolting the modules onsite rather than having the factory pre-drill the holes. “It added a few minutes per bolt, four times per module, across thousands of modules,” he said. “That adds up fast.” The surprises still come from below, though: one customer’s sloppy survey missed a 15-foot grade drop, forcing custom steel extensions on 15 foundations just to bring the canopy level.

For all the risk, Weaver is quick to say the work is worth doing. “Building carports feels like real hard-hat construction: trenching, pouring pads, burying conduit, long wire pulls,” he said. “It’s all very fulfilling.” The unifying lesson from all three panelists, and from Weaver, is humility. As Boyce put it, the purchaser of construction has to know when they do not know, and then trust the experts they hired. Flipping a house does not qualify you to build a 25-foot steel canopy that has to carry solar for 50 years. Carports reward the teams who engineer first, price the ground honestly, and treat the foundation as the project. Everyone else is gambling with their margin.