Lumber prices have continued to decline after soaring by around 300 percent over the year in May, when they hit record highs and added around $36,000 to the cost of an average new single-family home. As sawmills have ramped up output and buyers put off purchases, both spot lumber prices and futures contracts have seen a sharp drop since May’s peak of nearly $1,700 per thousand board feet, the unit of measurement for lumber in the United States. CME’s Random Length Lumber Continuous Contract (LBOO) front-month futures lumber prices were trading at $968.60 intraday on Tuesday, after closing at $996.20 on Monday, the first time the index fell below $1,000 since March. That’s down nearly 24 percent over the month, though still up over 157 percent over the year. In a sign that the downward trend may be poised to continue, the futures contracts for upcoming months show lumber prices for September …