How to Add a Toilet & Shower to a Garage

General Plan

• Figure out the best place for both a toilet and shower drain. You will need to determine how close the septic tank is to the new bath space or how to connect to the sewer. Go over ideas for insulating the space and heating it as well. You will need to route electricity from a breaker box for lighting and outlets, so take this into consideration during the planning stages. Be sure to review local building codes for a required window and vent in your bathroom space, too.

Bath Layout

• You will need a workable floor plan for the bath and garage spaces. The toilet and shower space will need a closable door, for example. Having this space near the garage walkout door might not work well, due to privacy issues. Planning the toilet and bathing area in a corner opposite the walkout door might work better.

Marginal Areas

• Framing the small room should allow adequate garage space. You don’t want to use up part of car stall space in a two-car garage, for example. Use an area at the back of the garage for the bath area that won't affect car space.

Concrete Protection

• Floor drains and tapping through concrete may require expert help. You can cause severe cracking in a garage floor by using the wrong methods. The garage foundation is a big concern as well. You will need to figure out the best way to tie drain lines to sewer lines without damaging garage foundation walls, too.

Warmth Issues

• Heating the bath space will be required to keep pipes from freezing. You can install a small electric wall heater. Leaving the heater on low heat will be required daily in winter months. This calls for excellent insulation in the bath enclosure space. Construct the bath walls with 2-by-8-inch boards, so you can install heavy insulation to keep the space warmer with less heat required.

Walls and Flooring

• Cover the walls with drywall before installing a premade shower. Having a small sink is always a good idea, too. Finish up walls and flooring before seating the toilet. You will need to seat the toilet on top of tile flooring, for example, for a professional look.

Door Insulation

• Hang a walkout door with a weather-tight seal, unless you heat all of your garage space. You will want to keep the heater on in certain months of the year, but you don’t want to unnecessarily lose bathroom heat inside the unheated garage.