How to Install an Attic Bathroom

Many homeowners expanding their families or simply interested in more space often look to that neglected area above their heads: the attic. Just like basements, attics are spaces that are ripe for expansion because large-scale structural building is kept to a minimum. Much of the building structure, consisting of exterior walls, roof, joists, and other expensive contractor-driven features, is already in place.

One feature that makes an attic bedroom so valuable for homeowner use and eventual resale is a bathroom. An attic bedroom without a same-level bathroom can be a tough sell, both for current occupants and for potential buyers. Learn the general outlines of installing a basic, lower-cost attic bathroom, whether this is a do-it-yourself project or one that you feel is best left in the hands of a building contractor.


Unlike upgrading an existing bathroom, installing a new bathroom can involve heavy plumbing and wiring work. This is not a project for beginners or anyone who is not a home improvement veteran. For an addition or renovation of this degree, our experts strongly recommend hiring a professional.

Assessing and Planning Your Project

Full bathrooms, consisting of a toilet, sink, and bathing facilities, add maximum utility and value to your attic. Full baths are also the most costly and labor-intensive type of bathroom to create since a bathtub or shower adds significant weight to the flooring, as well as creates more complications with water supply and drainage lines. Instead of a full bathroom, many homeowners decide to install a half-bathroom: sink and toilet only, with no bathing facilities.

Consider the placement of your attic bathroom. The highest possible ceiling for an attic bathroom is usually afforded by situating the room closer to the center of the home, where the roof peak is at its highest. Consider the vital services that are necessary for building a bathroom: electrical supply wires, water supply lines, branch drainage lines, sewer line, and vent stack. Since these services are found in the bathroom or kitchen on the floor below, it makes sense to locate your attic bathroom directly above either of those rooms, preferably a bathroom.

Developing a solid bathroom floor plan is critical to fitting all of the necessary items in this tight space. Begin by considering the largest item that will be installed in the space and working downward in size. If this will be a small full bathroom, a standard alcove bathtub size is 60 inches long. This means that the tub must be bounded by three walls, and the tub will fit tightly against the walls. Next in size is the bathroom vanity. If two of the walls are 60 inches long, then the other two walls should be longer than 60 inches to create a rectangular space that can fit a sink and vanity combination ranging from 24 inches to 36 inches wide. If room is at a premium, you may wish to install a space-saving pedestal sink.


Hiring a licensed contractor and bathroom designer are good investments when embarking on a large-scale renovation project.

Codes, Permits, and Regulations

Due to safety concerns, attic conversions of any type are controlled by building code. Check with your local permitting office about the types of permits you will need to apply for before building living space within your attic. In addition, bathroom additions in any section of the home always come with code restrictions and permit requirements.

Before You Begin

Costs for a DIY attic bathroom, like a contractor-built space, can vary enormously depending on its size, the features you choose to include, and the quality of the building materials you choose. In most cases, a skilled DIYer can do the work for about half of what it would cost with a contractor. But a simple bath with sheet vinyl flooring and prefab shower stall will be far more affordable than one with designer marble floor tile and a special-order whirlpool tub.

What Is Live Weight, Dead Weight?

Unless built expressly for the future addition of living space, the ceiling joists or rafter ties will need to be strengthened for the bathroom flooring. Attic floors often are built to accommodate only a maximum dead weight load. Dead weight essentially means an attic that is only used for storing boxes and for very limited traffic. Live weight load refers to the total weight carried by the floor, including furnishings, occupants, and all other permanent and temporary objects. Flooring joist span tables will assist you with information about whether you need to strengthen your joists. Better yet, consult with a structural engineer or a qualified contractor.

Disclaimer: Curated and re-published here. We do not claim anything as we translated and re-published using google translator. All images and Tattoo Design ideas shared only for information purpose.

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