With cost estimates for the border wall ranging from $10 billion to upwards of $25 billion, Mexican President Enrique Pena Nieto canceled his meeting at the White House Thursday after refusing President Trump’s demands that Mexico provide the money. But some American business leaders are looking past the political turmoil and getting excited about a massive infrastructure opportunity, which has already added about $2 billion in market capitalization to the stocks of U.S. construction companies.

The roster of eager executives includes Bill Sandbrook, CEO of U.S. Concrete (USCR) — yes, they supply ready-mixed concrete for all sorts of building projects — who spoke with Fortune about what it would take to build Trump’s wall. In addition to having met Trump personally prior to the election, Sandbrook, who is also an Army veteran, is better positioned to understand the ins-and-outs of building the wall than many other corporate leaders: U.S. Concrete’s headquarters, outside of Dallas, are some 400 miles from Mexico, and Sandbrook has seen the landscape at the border with his own eyes.

Although Trump has yet to release any specs for the wall, Sandbrook offered some context that illustrates how unprecedented the project really is. Mexico’s border with the U.S. is some 2,000 miles long, though roughly 653 miles (or almost a third) of it has already been fenced off in previous government projects. That leaves 1,347 miles needing a wall to comply with Trump’s executive order calling for a “contiguous land border between the United States and Mexico, including all points of entry.”

“I don’t think there are any walls of this length,” Sandbrook told Fortune. “Not of this scale since the Great Wall of China.” (China’s Great Wall is several times as long, running more than 13,000 miles in total.)

Here’s what else Sandbrook had to say about Trump’s plans to build the wall, edited for length and clarity:

What are your thoughts on President Trump so far?

President Trump is a doer, he’s a builder, he’s an outsider, he has a can-do American spirit focused on the U.S. And after the inauguration, what does he do? He does exactly what he said he was going to do. There’s a lot of details to be fleshed out in the policies I’m most interested in, which are tax reform, regulatory reform, and infrastructure, but frankly I’m extremely pleased with the follow-through.

What do you think of the wall?

Well in general, I’m apolitical on it. As far as the actual construction of a 2,000-mile structure, it’s yet to be determined what the primary materials are going to be, and right now it hasn’t been specified if there’ll be concrete in there somewhere, whether holding metal fencing into the ground or whether it will be a concrete structure itself. But we would vigorously look at the opportunity that might avail itself to be a material supplier for the project.

What would it actually take to build a wall at the Mexican border?

It’s a very rural, desolate area. There are not many concrete fixed plants in large segments of that geography. If it’s [made from] concrete, it would have to be done by portable plants where actually the plant is on the truck itself to supply it. It has to be local. You can’t ship this from 500 miles away; ready-mixed concrete is a local business.

This won’t necessarily be a super-complex or super-sophisticated concrete design. We did the Freedom Tower in New York, and that was very specialized, high-strength concrete. But concrete [for the border wall] doesn’t have to withstand the tolerance that going up 90 stories does.

Does the landscape along the border present other challenges to building a wall?

This would be more desert, high desert, rugged terrain. It’s a fairly remote, rugged area. A lot of that area doesn’t even have roads going into it, so it’ll be a fairly complex engineering feat. These rugged areas, you’re not driving 60 or 70 miles per hour, so [the concrete has to be relatively close by so that it doesn’t harden while in transit]. Another option is to construct concrete panels off-site and ship the panels, though they’re not the easiest thing to ship, especially across rugged terrain, because they tend to crack.

But I think it’s very doable. Even though it’s in rugged terrain, it’s not insurmountable by any means. But it’s long. It’s a long, long way from the Pacific Ocean to the Gulf of Mexico. We can build hundred-story skyscrapers in Manhattan. This is just the wall, it’s just long.

How big do you envision the wall being?

I can’t even dimension that because I don’t know what the specifications are going to be. People are talking about 13 feet [high], people say 30 feet; I’m withholding any speculation.

But this is not going to be a barrier designed to prevent the invasion of Normandy. This is not a barrier that needs to be 40 feet thick to stop armies. It’s probably going to be multiple materials depending on the segment being constructed. But there’s no question it’s going to be a physical wall.

How long do you think it will take to start building the wall?

The wall could be fast-tracked. Less than six months, more than one.

Do you have any estimates of how much the wall will cost?

There’s a lot of pundits out there kicking around numbers, but I think it’s premature because nobody knows what the design is. I’d rather withhold my judgment or withhold my judgment on our company’s opportunity til I saw more details. I’m not a pundit. I’m a CEO trying to look for opportunities to increase shareholder value.

Some investors have speculated that Mexican cement company Cemex (CX) could be a contender to build the border wall. Do you think U.S. suppliers have any advantage in the bidding for this project?

On the pipelines earlier this week, [President Trump] mandated domestically produced steel. He has an America-first agenda, and having a name like U.S. Concrete, you can’t get any more American than that.