In South Windsor, T&M Building Co. Inc. is just completing 155 townhouses, duplexes and detached homes; during the course of construction, lumber prices added an average of $18,000 to each one, said President Greg Ugalde. And even though Bristol’s Carrier Construction Co. has been a major homebuilder in the region for decades, this year it’s struggling to get some types of vinyl siding and plywood that usually are abundant. In a sharp reversal of the usual pattern in construction, Carrier now starts jobs by buying long ahead of when products will be needed. Demand for new housing is intense at all ends of the market, while labor costs are soaring and construction materials are often scarce and sometimes staggeringly expensive. Connecticut construction employment dipped at the start of the pandemic, but reached 62,700 last month, a 5.4% increase since February of 2020. About two-thirds of the country has had a rise in construction jobs, and Kenneth Simonson chief economist for the Associated General Contractors of America, doesn’t anticipate any imminent change.