A version of this article first appeared in the CNBC Property Play newsletter with Diana Olick. Property Play covers new and evolving opportunities for the real estate investor, from individuals to venture capitalists, private equity funds, family offices, institutional investors and large public companies. Sign up to receive future editions, straight to your inbox. U.S. homebuilders had hoped for a robust spring market this year after the winter brought falling mortgage rates and rising homebuyer demand. The war with Iran threw a wrench into that optimism, pushing rates higher and layering on big increases in costs for materials and transportation due to the spike in oil prices. Homebuilder sentiment in April, the heart of the spring housing market, dropped sharply, according to a monthly index from the National Association of Home Builders. “With oil prices higher in the U.S., 62% of builders reported suppliers have increased building material costs due to higher fuel prices, including gas and diesel,” said Robert Dietz, NAHB’s chief economist, in a release. “Energy costs make up approximately 4% of residential construction material input and service costs. With near-term economic risks elevated, 70% of builders reported challenges pricing homes given uncertainty about material costs.” A slew of building suppliers reported price hikes in April on everything from foam insulation and roofing to windows and doors. The cost of both manufacturing these products and transporting them has increased quickly. “We’re starting to hear more about subcontractor and supplier price increases along with freight and fuel surcharges,” said Rick Palacios, director of research at John Burns Research and Consulting. JBRC surveyed homebuilders on this topic in early April and found 38% of …