The foundation and frame are the most expensive materials when building an addition to the house. Both are necessary for a safe and sturdy structure, and you have less room to maneuver to choose cheaper options. On a larger scale, the labor cost to build an addition can also exceed the cost of materials, but this is highly dependent on your design. Like electrical work, plumbing work is done by licensed professionals; the more plumbing work, the higher the total cost of the addition.
Plumbing work must be linked to existing pipes in the main house.
