How To Rough In A Double Sink Vanity? 5 Easy Process

Are you looking for ways to rough in your double sink vanity? No worries, you’ve come to the right place.

How To Rough In A Double Sink Vanity

Firstly, what does it mean to rough in a vanity? Rough-in is a stage in the plumbing process where electrical, mechanical, and plumbing lines are brought in through bored holes.

Parts such as the faucets, sinks, and any other fixtures are yet to be installed in the rough-in process.

If you have the right drain assemblies, and all the necessary tools and fittings, you can easily do this process at home. Because the cost of bringing in a professional for this installation can be quite high- a lot of people keep wondering how to rough in a double sink vanity at home.

Today, we will cover all the basics of this issue. So without further ado, let’s get started!

What Is Rough In Plumbing?

How To Rough In A Double Sink Vanity

Rough-in plumbing is a kind of preparation process. Here, holes are bored in the framing studs. The holes are also bored through the flooring. It is through these holes that the water supply pipes and drainage will run.

After this, the connections are made to attach sinks, faucets, and other plumbing fixtures.

The “rough” In this unfinished process refers to the parts of the pipes that remain behind the doors of the vanity cabinet. This is the dead-end of the pipe.

Benefits Of Double Sink Vanity

Benefits Of Double Sink Vanity

Besides giving you extra space, a double sink vanity can also look quite luxurious in a bathroom space. If you have a lot of family members, a double sink vanity will be quite useful for your household.

Adding a double sink vanity also adds value to your home. Adding this double sink instantly uplifts your house and makes it more attractive for any potential buyers.

You might have heard realtors refer to a “his and her” sink in the bathroom. Although it might not seem like a big deal, it can truly hike up the price of your house if you’re planning on selling it.

Factors You Need To Know About Rough-In Process

Factors You Need To Know About Rough-In Process

Before you start to rough in a double sink vanity at home, you first need to familiarize yourself with a few important plumbing terms. Here are some things that you need to know about before getting started on this job.

1. Centerline

Simply put, this is the center part of the unit that you are installing. Let’s say you are setting up two pipes for your vanity. The centerline in this situation might be 10 inches.

This measurement means that the two pipes that you are installing need to be 10 inches apart from each other. This measurement is taken from the center of each pipe.

A lot of the time, measurements are taken from the center of the pipeline instead of the edge of the sink. If you are not sure about the centerline of the plumbing problem, you might have to redo the entire task.

That is why it is quite important to know where the center point is and how much it measures.

2. Dimensions

The dimensions of your double sink van deep will depend on the model that you have bought.

You will have to collect information about the dimensions of the front buffer of the fixture, vertical discharge, horizontal supply line, vertical supply line, and the side-to-side buffer of the fixture.

3. Base Floor

A base floor is a sort of proxy or rough floor that is installed before the permanent or final flooring is set up. This is typically laid when a lot of the construction is complete but the finishing touches have not been applied yet.

4. Supply Line

Supply lines are holes that are sometimes horizontal and sometimes vertically placed. Where you position the supply line will have a huge impact on the sink’s location and distance.

If you are using a vertical supply line, it has to be positioned about two to three inches above the drain pipe. On the other hand, a horizontal supply line needs to be placed 4 inches away from the centerline. The horizontal supply lines are placed on both sides of the centerline.

5. Sink Placement

Typically, a sink is placed 31 inches above the floor. It is just a general measure and can be customized according to your needs.

6. Discharge Hole

A discharge hole is always vertical. Usually, for a sink that has been placed 31 inches above the flooring, the discharge hole is 20 inches above the floor.

7. Front Buffer Of The Fixture

It is recommended that the minimum distance for this part is 30 inches. But, a lot of plumbers also use 21 inches. A plumber selects the distance based on the plumbing needs and given situation.

8. Side Two Side Buffer Of The Fixture

Side to-side buffer of the fixture is placed 15 inches apart from the centerline. Sometimes this is increased to 20 inches.

Products That You Will Need To Properly Rough In A Double Sink Vanity

Here is a list of all of the things that you will need for a proper rough-in.

  • Two Faucets
  • Two Sink Drain Assemblies
  • Saw
  • Yardstick Or A Tape Measure
  • Two 90° Drain Elbows
  • P-Trap
  • P-Trap Extension
  • Drain Trap Adapter
  • Pliers
  • Two Double Outlet Shut-Off Valves
  • Four Mesh Flexible Faucet Hoses

An Easy Guideline of How To Rough In A Double Sink Vanity?

Now let’s get into the rough-in process. Here is a guideline that you can follow to rough in a double sink vanity successfully.

1. Prepare And Measure

The first thing that you will have to do is take all the measurements. The measurements that you will have to take will also depend on the kind of fixtures that you want to install.

For example, if you want that both the sinks will share a grain, you will have to install the sinks with a minimum gap of 30 inches. Remember to take these measurements from the center of the sink.

2. Attach The Drain Assembly

Next, to make things a little bit easier, you can attach the drain assembly for the sinks. Do this for both of the sinks for better efficiency.

This step will help connect the p-trap and the sink. Try to bolt down the faucets on the sinks beforehand as well.

Any kind of fasteners that you will need- will probably be added with your purchase. Although it might seem like a weird thing to start the assembly before the plumbing, it is something that Will help you further down the installation process.

3. Level

Leveling the sink and fixtures is also quite important. Place the drain opening against the wall and use a leveler to do this. Use a tape measure to point out the height at which it is leveled. It is at this point that you will set up the tee.

A tee helps join sink drains easily using a simple p-trap. You need to note down the measurements of the distances from the level point to each drain tailpiece.

4. Cut The Piece

Cut the piece by using a saw. When cutting the pieces, make sure they are vertical from each drain. Also, ensure that you leave space for the extending pipe to have a ¼ inch per foot slope.

After cutting the pieces, you will have to attach the 90° elbow to it. If the connection has been properly made, you should be able to attach the two elbows and the tees easily. If they are not connected easily, you have made a mistake in taking the measurements.

Note: Here are our top picks of PEX Cutter that also you can use

5. Connect The Pipes

Now, you have to connect the p-trap to the tee. To do this, point down the tee. Sometimes, you might need an adapter to make this connection If the drain pipe is wider.

6. Take Away The Shut Off Valves

Turn off the water and remove the shot of valves from both the cold and hot water supply pipes. There has to be a double outlet valve in which you will connect the two hoses.

7. Connect The Fixtures And Valves

In the last step, you have to connect the fixture- meaning the faucet to the valves. Using a faucet supply tubing constructed of mesh is better for this step. The mesh faucet-supplied tubing is easy to cut and adjust.

Use a set of pliers to tighten the joints and the installation is complete. Don’t make the connections too tight or else you might break a joint.

Frequently Asked Questions

1. Can You Tighten The Joints By Hand?

If you have no other option left, you can sometimes use your hands to tighten the joints. But this will mean a loose connection and will possibly lead to a leak.

That is why using a plier is always recommended for tightening the joints.

2. Can One Drain Be Used For Two Sinks?

Yes, two sinks can share one drain. For this, you have to check if this complies with your local code.

The installation can be made very easily using the proper tools.

3. Do I Need Two Traps For A Double Sink?

Usually, a double sink will not require two traps. You only connect the tee to the sinks and then feed the tee through one p-trap. This p trap well then connects to the drain.

4. What Is The Standard Rough In Height For A Vanity Drain?

The lines are usually 20 to 18 inches high.

Final Words

If you have the proper supplies, you can easily rough-in sinks on your own. Now that you know how to rough in a double sink vanity, this process should be even simpler for you.

Even though you know all of the steps that you need to follow now, you should still understand that sometimes a plumbing problem can get out of hand. In such situations, it is better to call in for professional help rather than try your techniques.

Making an irreparable mistake can cause damages worth thousands of dollars.

To avoid such issues, try and follow the guidelines for a double sink rough in carefully. Just buy the right products, and follow the steps attentively. Then this should be an easy process for you.

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