WASHINGTON, D.C. — West of the US Capitol Building, all that remains of a 50,000-seat football stadium are a few old signs and a dusty field full of gravel. …The site is now awaiting a new, US$3.7-billion stadium due for completion in 2030, with the surrounding parking lots later to be transformed into 5,500 housing units, commercial spaces and a new road system. But to give the NFL’s Washington Commanders a new home, the stadium’s developers will need to navigate a difficult construction environment that has slowed building across the US, one marked by rising material costs linked to tariffs, as well as fluctuating oil prices and a tight labour market. …“Just recently, we added a clause to our contracts about escalation of material costs,” said Justin Holtzman of Artisanal Builders, a general contractor, which works in Virginia and Washington. …Given the trade war with Canada, “we have to protect against that risk.” [Full story access requires a Globe and Mail subscription]