A bathroom addition can range from a small half-bath (sink, toilet and mirror) to a spa-like master bath. Adding a bathroom is usually more expensive per square foot than other rooms because it requires specific types of plumbing, heating, electricity and ventilation.
Typical costs:
Converting existing floor space inside a garage, basement or attic into a simple bathroom starts around $3,000-$6,000. However, costs can be $7,000-$25,000 or more for a more luxurious bathroom, or if the new bathroom is far from existing water and sewer lines. Prices may vary significantly by region, depending on local labor rates.
Costs for do-it-yourself materials start around $500-$1,500, but can run $2,000-$5,000 or more depending on room size, the quality of fixtures and other amenities. A Pennsylvania homeowner added a 4x8-foot powder room with granite and upgraded fixtures for about $5,000, doing all the work himself except the rough-in plumbing.
Adding new floor space to your home for a basic 6x8-foot bathroom addition starts around $25,000-$50,000 and goes up depending on complexity, quality of fixtures, number of amenities and local labor rates. Remodeling Magazine pegs the price of a 6x8-foot bathroom addition at averages of $33,188-$41,195 in the Midwest, $34,876-$42,491 along the East Coast and $35,987-$47,052 in the Western states. For a spa-quality 100-square-foot master bath the survey says it averages $75,812 nationwide.
What should be included:
If you're adding new floor space, before you do anything else check with your local planning department. Better Homes and Gardens provides an overview of legal remodeling requirements.
As a general rule, a half-bath should be at least 3-4 feet wide and 6-8 feet long, or at least 18 square feet; a bathroom with shower should be 30 square feet or more; and a bath with both a shower and tub should be at least 35 square feet. ThisOldHouse.com explains how to plan a half-bath (also called a bonus bath) while RemodeOrMove.com lists things to consider for any size bathroom addition.
Additional costs:
Adding a tile floor, marble counter tops, or other upscale features can dramatically increase the weight load on your foundation. You might need to consult with a structural engineer (anywhere from $300-$800 or more, depending on what's needed and rates in your area) to see if the foundation needs to be reinforced.
Hiring an architect to create a set of plan drawings could cost you a flat fee of $700-$30,000 or more, depending on size and complexity, or the architect may charge 5-15 percent of the project's costs.
Usually a bathroom addition will trigger a reassessment of your property taxes and a resulting tax increase, but in most areas the reassessment will only be on the value of the addition, not the entire house.
Bathroom design books cost $10-$40 or more, and can give you great ideas and tips; they may also be available at your local library.
Shopping for a bathroom addition:
Gather photos of bathroom styles and details that appeal to you. Better Homes and Gardens displays a slide show of contemporary styles and Kasmar Publications posts pictures of luxury bathrooms.
If you want a remodeling contractor to handle all aspects of your bathroom addition, the National Association for the Remodeling Industry provides an online booklet with tips for hiring a contractors, as well as contractor referrals.
Check whether a contractor is licensed in your state, and if there are any complaints with the Better Business Bureau. A written contract should include a detailed outline of the work required and materials used, dates within which the project will be done, and a payment schedule.
To break concrete floor and install drainage and vents I hired a plumbing company, which was $4500. I did the remainder of work including electrical and other.
Would like to add upstairs bath - What is the cost???
Amount: $5,000.00 total
Posted by: JT in Minneapolis, MN.
Posted: April 26th, 2012 09:04AM
Square Feet: Approx. 40
Contractor: Self and outside
I would like to get and estimate of how much it would cost to add a master bath to the upstairs of my 1.5 story house. Using existing floorspace, framining myself and installing pre-fab vanities, sinks and showers. Hiring for outside plumbing. Bathroom would be about 10-15 feet from existing plumbing a floor below. Any thoughts on how much this will run me???