Adding a bathroom to an attic during an attic conversion project can be costly if there are no basic plumbing needs running to the attic. To calculate the cost of an attic bathroom conversion, you need to consider a wide range of construction elements and contractor questions.
Consider all the work that will need to be done to create a bathroom in your attic. This should include the pipes, electrical, insulation, walls, added floor supports, flooring, defined access to the attic and a possible window. This will all depend on the current condition of your attic.
Take all the required measurements for the insulation, drywall, paint and other supplies you need to buy. Calculate the amount of linear footage that needs to be finished. Unless you are experienced with electrical and plumbing repair, you should call a contractor for an estimate and to do the work for these systems.
Check your projections against those of the pros. Use the remodel calculator at Remodel Estimates and see if you are in the ball park (see Resources below). Consider the differences in labor and materials from one region of the country to another.
Decide if adding a bathroom to your attic is the right move for you. Though the cost can be high, this particular remodel can increase the value of your home; both the finishing of the attic, which adds square footage to your house, and the addition of the bathroom are considered major upgrades on the real estate market.
To find out what the average cost of construction labor is, contact a local contractor for an hourly estimate and for the estimated hours of your project. You do not need to get an official bid--this is for information purposes only.