cost per square foot to build a home addition
Primary factor, specifications of in the room addition plans. Examples: 1  Home addition cost estimates of $80 to $130 per square foot for a basic family room addition is common. 2  If the home addition includes a bathroom and/or a kitchen, the room addition costs can easily escalate to $200-250 per square foot. The above figures place the cost of the addition at $124 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.