I bought a house with an unfinished bathroom in the basement. The builder had roughed in the electrical and plumbing connections, including the sewage basin set in the concrete slab floor. Also see How to Finish a Basement Bathroom – The Complete Series for the project overview.
How to Finish a Basement Bathroom Steps
The remaining tasks to finish the basement bath are:
- Obtain a building permit.
- Paint the walls.
- Install a ceiling ventilation fan.
- Install a vent to the outside for the fan.
- Build the shower stall.
- Tile the shower and floors.
- Install the shower hot & cold water supply lines.
- Install the shower head and valve.
- Install the toilet.
- Install the sink and vanity.
- Install a light and mirror over the bathroom vanity.
- Install an electrical outlet for the sewage pump.
- Install the sewage pump.
- Connect the outside vent pipe to the sewage basin.
- Connect the sewage pump to the main sewer line.
- Connect the bathroom hot and cold water lines to the main supply lines.
- Test the plumbing connections and sewage pump.
- Obtain final inspections from the Building Dept.
It seems like a lot of work… and it is. It took me the equivalent of seven (7) eight hour days to do the job, working weekends at my own pace. A professional 2- or 3 man crew could knock it off in 3 to 5 days. I received quotes at around $5,000 just to build the shower basin, set the toilet and hook up the sewage pump. Most of the contractors I spoke with didn’t want to pull a building permit – which would require code inspections – always a cause for concern over the quality of work and compliance with building codes.
Basement Bathroom Plumbing Rough-In
The 5 feet wide by 11 feet long bathroom was bare walls and concrete floors with stubs for the plumbing rough-in as installed by the home builder. Notice the rough hole in drywall on the left. The sewage basin is in a sealed room through this hole. More on this later.
The plumbing hookups for the sink and toilet are shown here.
Notice the large hole in the drywall above the shower drain rough-in in the picture below. The utility room for the sewage basin is through that hole.
The ceiling had only a naked light bulb and electrical box. This will be replaced with a combo ventilation fan and light.
Install a Door to the Plumbing Utility Room
The first thing I need to do was get access to the wet wall (where the plumbing lines are located) in the small, unlighted and inaccessible utility room where the sewage basin is located. The only way into this utility room was through through the rough hole in the bathroom drywall where the shower stall would be built!
To solve the access problem, I installed a pre-hung door in the non-load bearing wall of the room adjacent to the bath. I began by handing a flash light and drill to my son and asked him to crawl through the hole into the utility room. Poking my head through the hole, I instructed my son to drill four small holes just inside the wall studs. This gave me reference marks on the other side of the wall in the game room to cut out the doorway, frame-in and set the door.
Here’s a photo of the newly installed door to the basement bathroom utility room:
The utility room and plumbing layout is explained in the next photo. The basement ceiling is 17 feet high because the house sits on a hill side, so I stacked two photos to show the entire scene.
Now that I have easy access to the utility room through the new door, I installed a steel junction box, light switch (blue box) and florescent light. The electrical wiring was easy working on an unfinished wall and I was able to tap into an existing permanent electrical circuit.
The basement bathroom toilet, sink and shower drain into the sewage basin. The sewage basin was installed by the home builder and is shown here with the metal cover. The holes in the cover for the plumbing and electrical connections can’t be seen because they’ve been taped over and covered with dust.
The interior of the sewage basin is shown below. The basin is about 32 inches deep. Sewage empties into the basin from the inlet on the right. The inlet on the left is sealed. When the basin is installed, the builder decides which inlets(s) are needed and the outlet cover is cut out to connect the incoming drain pipe(s).
A submersible sewage pump is necessary to lift the effluent from the basement level to the main sewer line overhead. The following photo illustrates how the sewage basin and pump operate. Image is Copyright Liberty Pumps, Inc.
The project is continued in How to Finish a Basement Bathroom – Part 2.
After you’ve finished the basement bathroom and have run out of things to do (smile), consider reading How to Finish a Basement Bedroom.