Across-the-board double-digit gains in all three construction categories fueled South Carolina’s September contracts to a 35% overall gain for the month, according to McGraw-Hill Construction. The company, publisher of Engineering News-Record, estimated the state’s September contracts at $479 million.

The nonbuilding category, which includes infrastructure work, increased by 42% compared to last September, for a total of $89.4 million. Nonresidential contracts jumped 36% compared to a year ago for a $122.2-million monthly tally. The value of new residential contracts increased 33%, for a total of nearly $267.4 million.

McGraw-Hill Construction now estimates South Carolina’s 2011 contracts at $5.3 billion overall, which is a 2% improvement over the same period of a year ago.

The nonresidential category has produced the greatest gains to date, generating more than $1.7 billion in 2011 construction contracts, or 24% better than a year ago. Residential contracts have improved by 4%, for a nearly $2.6-billion total. Despite the monthly gain, the nonbuilding category is still 26% lower than a year ago, with about $999.6 million in new contracts.