cost to build a sunroom
1 The above figures place the sunroom addition at $360 per square foot. 2  This pricing structure assumes that carpenters charge an average of $70 per hour, electricians between $65 to $85 per hour, and painters between $20 and $35 per hour. According to Hanley Wood and their Remodeling magazine the average sunroom addition in which a slab is poured, post and beam construction is used, and a four-season space is created will cost $72,000.