Convert an Unfinished Laundry Area Into a Laundry RoomUpdated: Mar. 15, 2023
Make your laundry room more attractive and functional by reworking the plumbing and adding a new sink and countertop.
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Your laundry room doesn’t have to be a dingy, disorganized place full of cobwebs and dust bunnies. In this article, we’ll show you the first steps for converting an unfinished laundry area into a finished room. We’ll focus on the most useful upgrade—replacing your old laundry tub with a new, tidy countertop and sink. It involves rerouting plumbing in the walls and installing new cabinets. However, we won’t go into detail about cabinet installation, lighting, wall finishing, flooring or moving electrical outlets. A total laundry room makeover is an ambitious project, since it involves both electrical and plumbing skills. It’s not for a beginner. Altogether it’ll take four to five weekends to finish.
If your plumbing system is all plastic, you’ll only need basic carpentry tools. If you have copper water supply lines, you’ll need a tubing cutter and soldering tools. A hole saw might be required to drill 2-1/2-in. holes through studs.
The cost of materials for this 8 x 12-ft. room was about $2,000. This includes about $1,000 for cabinets, countertops and shelves, and $500 for the vinyl floor tiles.
Planning the makeover
Photo 1: Cut out the vent pipe
Shut off the main water valve and open the laundry tub valves to drain the water. Cut out the old water supply lines. Disconnect the old trap and cut the drain and vent pipes with a hacksaw or reciprocating saw.
Replacing the freestanding laundry tub with a drop-in sink frees up space and makes it easier to install a usable length of countertop. Adding a washing machine outlet box at the same time allows you to tuck the washing machine’s water supply and drain hoses neatly out of sight when you cover the bare studs with drywall.
If possible, leave the dryer in about the same spot so you don’t have to move the dryer vent and electrical or gas connection. Also keep the washing machine and the new sink on the same wall as the existing plumbing. You can easily move the sink and washing machine drains several feet, but relocating them to a different wall will sharply increase the difficulty (and cost) of this project.
Measure your laundry room and draw a floor plan showing the new cabinets, sink and appliance locations (Figure A). Use the plan to determine the location of the drains and supply lines. Center the sink plumbing on the sink base. Locate the plumbing box for the washing machine slightly below the top edge of the machine.
Draw a sketch of your proposed piping layout, including pipe sizes, and show it to the inspector when you apply for the permit. Use Photo 4 to help with the drains. Remember to call for an inspection before you cover the pipes with drywall. While the wall cavities are still open, add countertop outlets and new lighting. The electrical code requires a separate 20-amp circuit for laundry outlets and GFCI protection for outlets within 6 ft. of the sink. Put all light fixtures on a separate circuit.
For the tidiest appearance, rework the dryer vent to fit within the wall. Use 4-in.-diameter aluminum or galvanized metal ducting, not the flexible kind.
Start by disconnecting the washer and dryer and moving them out of the way. If you have a gas dryer and you’re unsure how to safely disconnect it, call the gas company or a plumber for help. Use a hacksaw or a reciprocating saw fitted with a metal-cutting blade to cut the old drain and vent pipes (Photo 1).
Cut the drainpipe about 2 in. above the bottom wall plate. Cut the vent pipe at 50 in. from the floor. Don’t worry if your drain and vent pipes are metal rather than plastic. Just choose the appropriate size transition coupling (Photo 2) to join the metal pipe to the new plastic pipe.
Shut off the main water valve before cutting the hot and cold water lines. Be prepared with a bucket and rags to catch any water that’s left in the pipes.
Figure A: Plan for New Plumbing
Measure your laundry room and sketch in the positions for a new countertop, sink and washing machine outlet box. Reroute the supply lines, drains and vents to these new positions.
Install the plastic drain and vent pipes
Photo 3: Assemble the piping
Cut, prime and glue together the plastic piping and fittings to fit between the existing drain and the vent. Connect the new pipes to the existing pipes with transition couplings.
Start by laying out the pipe route. Here are a few plumbing code requirements and tips to guide your plan:
- Run a 2-in.-diameter drain to the washing machine.
- Slope drainpipes down 1/4 in. for every foot they travel horizontally.
- For 1-1/2-in. drainpipe, limit the distance from the P-trap to the vent to 42 in. For 2-in. pipe, limit the distance to 60 in. (Photo 4).
- Install any horizontal section of a vent pipe at least 6 in. higher than the overflow level of the fixture it’s venting (for laundry sinks, this is the top edge).
- Slope vent pipes slightly downward toward the drain.
- Position the sink drain about 3 in. below the bottom of the sink. In most cases, a height of about 16 in. from the floor will work.
- Locate the top of the washing machine outlet box just below the top edge of the washing machine, usually 42 in. from the floor.
- Before you buy your plastic fittings, note the subtle differences in the types required—sanitary tee, cleanout tee, etc. (Photo 4).
Mark the pipe route on the studs. The easiest way to run drains is to notch the 2×4 studs for the new plumbing pipes. Then add 2×2 strips to reinforce the studs later (Photo 5). But don’t notch the studs if your laundry room wall is a “bearing” wall—that is, if it supports a floor or roof above it. If you’re not sure, consult a building contractor or architect. If your walls are 2x6s, you can skip the notching; it’s generally easier to drill holes in the center of each stud for the pipes.
You’ll need a 2-1/2-in. hole saw or auger bit and a powerful drill. One disadvantage of the hole method is that you may have to cut long horizontal pipes into shorter lengths and join them with couplings to fit them in. Install metal nailing plates to protect any plastic or copper pipe that is within 1-1/4 in. of the face of a stud.
Start the drain and vent pipe installation by cutting and gluing the pipe and fittings that fit between the existing drain and the vent pipes (Photo 3). Begin at the drain and work up. At the top joint, roll the rubber sleeve on the transition coupling back onto itself to provide clearance for the vent line connection (Photo 3).
Then roll the rubber sleeve down onto the plastic pipe, slide the metal band over the sleeve and tighten the band clamps. Complete the drains and vents by cutting, priming and gluing the remaining pipe and fittings (Photo 4).
Run the supply lines
Photo 5: Run supply lines to the laundry box
Screw the laundry box to 2×2 furring strips. Solder copper pipe to the shutoff valves and mount the valves in the laundry box. Solder the remaining copper supply lines and fittings.
Start by planning the route of the supply pipes and drilling 3/4-in. holes through the studs. For serving the sink and washing machine, 1/2-in. pipes will do. Cut and solder in copper lines and fittings. (Glue CPVC pipe.) Mount a copper strap, available at home centers, about 4 in. below the stubbed-out sink drain (Photo 6).
Then solder the stubbed-out copper pipes to the strap to support them. To avoid melting the plastic washing machine outlet box with the torch, solder the vertical lengths of copper tubing to the laundry valve before mounting the valve in the box. Leave the pipes long and cut them to fit later (Photo 5).
When you’re done with the copper water piping, close the laundry valve and open the main water valve to check for leaks. If there are no leaks, you’re ready to call for a plumbing rough-in inspection. At this point, complete the wiring. When the plumbing and electrical rough-in work is complete and approved by the inspectors, hang and finish the drywall and install the base cabinets.
Install the sink cabinets
Photo 7: Install the angle stop valves
Fit the sink base over the stubouts. Then cut the copper pipes about 2 in. beyond the cabinet back and install the angle stop valves. Cut back the PVC drainpipe and glue on a 1-1/2-in. trap adapter.
Photo 8: Install the sink
Make the sink cutout in the countertop with a jigsaw. Mount the faucet, the supply lines and the drain on the sink. Then lay a bead of tub and tile caulk around the cutout and drop in the sink.
Before you install the sink base cabinet, lay out the positions of the water and drain stub-outs on the back of the sink base. Drill clearance holes for the stubouts, working from the inside of the cabinet so any splintering will be hidden. Then install the cabinet.
When you’re done installing the base cabinets, cut the countertop to length and fit it to the walls. Then mark the sink cutout on the countertop following the instructions included with the sink. Some sinks include a cutout template. Otherwise use the sink as a template.
Mark around the perimeter. Then draw a second line about 1/2 in. inside the first. This will be the cutting line. Drill 1-in. corner holes and cut the hole with a jigsaw. Support the cutout to prevent it from falling as you finish the cuts. Put the countertop back onto the cabinets and attach it from below with screws. Make sure the screws aren’t too long or they’ll pop through the top of the counter!
Next, shut off the main water valve and cut the capped ends of the stubbed-out copper pipes. Install compression-type shutoff valves (“angle stops,” Photo 7).
Install the faucet on the sink according to the manufacturer’s directions and attach the water supply tubes before you mount the sink in the countertop (Photo 8). The plastic sink we used did not have any faucet holes. We drilled them with a hole saw to fit our faucet.
Test-fit the sink. Then place a bead of tub-and-tile caulk around the perimeter of the sink cutout before you set the sink permanently in place. Attach the supply tubes to the stop valves. Then trim the length of the tailpiece and the waste arm as needed to connect the sink trap (Photo 9). If either the tailpiece or the waste arm is too short, you can buy longer ones or add extensions. Turn on the water and test for leaks.
Reconnect the washer and dryer
Connect the washer to the new valve with hoses (Photo 10). (For an extra measure of security, we recommend you buy “no-burst” laundry hoses.) Use a sharp utility knife to cut out the plastic cover over the drain hole in the laundry box. Then place the end of the drain hose from the washing machine about 3 in. down into the drain hole.
A new washing machine may include a clamp or gasket to secure the drain hose to the washing machine outlet box. Otherwise, drive a self-tapping sheet metal screw into the plastic box and wrap a zip tie or wire around the screw and hose to keep the hose from falling out.
At this point, you’ve done the hardest part. Finish wiring the electrical outlets and lighting, install flooring and hang your wall cabinets and shelves.
Required Tools for this Project
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
- 4-in-1 screwdriver
- Cordless drill
- Drywall saw
- Nut driver
- Pipe wrench
- Plumbers tape
- Slip joint pliers
- Soldering torch
- Tape measure
- Tube cutter
- Utility knife
- Wrench set
Required Materials for this Project
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.
- 1-1/2 in. plastic trap assembly
- 1-1/2 in. sanitary tee
- 1-1/2 in. trap adapter
- 1-1/2 in. vent pipe
- 1/2 in. copper pipe
- 2 in. drain pipe
- 90-degree long turn elbows
- 90-degree vent elbows
- Cleanout plug
- Compression angle stops (2)
- Copper strap
- Shutoff valves (2)
- Supply hoses (2)
- Supply lines (2)
- Transition couplings
- Washer machine outlet box