Pedestal sinks are ideal for many bathrooms, particularly small, cramped bathrooms without room for a full, expansive vanity-style sink. Many times, pedestal sinks feature beautiful, elaborate, decorative bowls resting atop a column hiding the drainpipe and water lines. The bowl usually rests against the wall, with fasteners helping hold it in place.
Given the different setup and design of pedestal sinks, completing the rough-in plumbing looks slightly different from other sinks. If you’re replacing an old sink with a pedestal sink, you’ll probably have to open the wall to expose the studs. Either way, this article should (hopefully) lend some clarity surrounding the process.
What Is The Drain Height For A Pedestal Sink?
The standard bathroom sink height ranges from 29 inches to 36 inches. For the most part, pedestal sinks are between 29 and 33 inches high.
Every pedestal sink varies slightly from the next, so specific instructions may not look quite the same. However, the drain height for a pedestal sink usually sits between 22 and 24 inches from the finish floor.
From there, the sink drain itself is often situated roughly four inches inward from the water supply line. The water supply line for a vanity sink runs out of the wall and into a hole in the backside of the vanity.
There are a few things that need to feed into the hole in the back of the pedestal sink, including the water supply tubing, drain stub-out, and so on. They must line up directly with the pedestal, which helps hide the P-trap and supply stub-outs.
Some pedestal sinks have a built-in alcove that helps hide the supply valves, while other designs require you to place the supply valves as close to the bottom of the sink as possible to hide them. Make sure you install them with enough clearance for the sink.
How Do You Rough-In Plumbing For A Pedestal Sink?
Completing the rough-in plumbing for a new pedestal sink in your bathroom isn’t particularly difficult. With a bit of know-how and a few tools, you’ll have the job done in no time. However, before you start working on the plumbing, check your area’s plumbing and building codes.
In some cases, the code may require that plumbing connections are made by licensed plumbers. If that is the case, you’ll have to enlist the help of a licensed professional.
Here’s what you’ll need:
- 2×4 inch blocking boards
- Hammer or screw gun
- Nails or screws
- PVC pipe
- Copper tubing
- PVC cement
- Propane torch
- Fine sandpaper
- Solder flux
- PVC P-trap
- Water shut-off valves
Check The Installation Instructions
Before starting, check the installation instructions that came with the sink. You’ll need to know the specific dimensions associated with the sink to install it correctly. As you move through the installation, refer back to these instructions periodically.
First, you need to install blocking between the studs in the wall. To do so, mount 2×4 inch boards between the studs at the mounting height for the bowl. You’re going to fasten the sink to the blocking strips.
Attach the blocking strips to the studs with screws/nails and a screw gun/hammer. If you’re installing a pedestal sink in an existing bathroom, you will need to open the wall to access the studs at the right height. So, refer to the instruction manual for the proper installation height.
Install The Water Supply And Drain Pipes
Next, refer to the instructions for the correct height of the water supply and drain pipes. Install the drain and copper pipes for the water supply using PVC pipe. Attach them to the main supply and drain lines in the basement or crawl space.
Attach the PVC using PVC cement and cleaner. To do so, swipe the cleaner around portions of the PVC fittings, then apply the cement to both pieces of the pipe. Twist them together, then hold them for a few seconds to let the cement set.
Or, with copper pipes, solder the tubing ends together. Start by cleaning both ends of the tubing with fine sandpaper, then spread flux on the pipes and slide them together. Using a propane torch, heat the solder until it starts to melt, then run the solder all around the seam.
Prep The Water Supply Lines
The water supply lines need to extend about two inches past the face of the wall. So, run them through holes drilled in the wall covering, ensuring two inches protrude from the wall. Then, extend the drainpipe horizontally, making sure about a foot of it extends from the wall.
Figure out the distance from the center of the sink drain to the wall, then mark the correct length on the PVC drain pipe. Hold the P-trap with an elbow centered on the mark, then use a hacksaw to cut the drainpipe at that exact spot. Make sure you make a square cut.
With the pipe extending to the right length, it’s time to solder the shutoff valves. Solder the valves to the water supply lines extending from the wall. Keep the ends open to connect the water lines from the sink once you maneuver it into place.
Attach The P-Trap
Connect the P-trap and the drainpipe using a compression connector on the trap. These connectors feature rubber or plastic washers that compress once the mounting nut tightens, thus sealing the joint.
Shut-off valves and P-traps feature covers that slide over the pipes and fit against the opening in the wall. So, before you tighten the connections, make sure those are in place.
Ensure the P-trap connection sits level with where it meets the drain pipe from the wall. Double-check that the vertical opening on the other side will connect correctly with the sink’s drain.