Connecting Sink Drain To Wall Pipe

October 14, 2022

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Identify The Fittings You Need

How to Plumb a Drain – Sink Drain Pipes

If you are connecting PVC pipe to PVC, the fittings you need will be the same as the ones present already. If you are splicing in PVC to copper or cast iron, you will need transitional fittings with a rubber coupling and stainless compression bands. These are widely available in most hardware stores.

If you are replacing the entire P-trap and the tailpiece, you can buy these ready to install. As you are already replacing the drainpipe, it is worth replacing the P-trap and the tailpiece too. It will refresh the pipework and keep everything in good order. Plus, these pieces wont take too much money out of your wallet, and they take no time to install.

How Easy Is It To Install A Kitchen Sink

The trickiest part of installing a new sink and faucet is connecting the sinks drainthe pieces between the sinks tailpiece and the waste line. Always start at the sink tailpiece and work down. This is where a swivel P-trap with a trap adapter earns its keep. It can swing side to side on two different axes and adjust up or down.

Before you head off to the store, Richard recommends drawing a map like the illustration here and checking the inside diameters of the tailpiece and waste line, usually 1 ½ inches. Then, instead of buying a kit, get only the pieces you need, including Schedule 40 PVC pipe to cut and fit as needed.

Check The Drain Outlet Height

Before removing the old sink and buying a new kitchen sink, it is a good idea to check the height of the trap arm on the old sink. The trap arm is the horizontal piece between the U-shaped trap bend and the branch drainpipe in the wall. It connects to a sanitary tee fitting in the branch drain and should slope down toward the tee at about 1/4-inch per foot for proper drainage.

Measure up from the floor or base of the cabinet to the center of the trap arm. If the height is more than 16 inches, you may find that a new sink will not allow for the necessary downward slope for the trap arm.

The Spruce / Kevin Norris

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Why Are The Pipes Under My Sink Leaking

Arguably the most common reason you’ll find water beneath your sink is that your drain has a leak in it. Shifting plumbing lines, worn-out connections, or even pipe corrosion could cause fractures in the plumbing lines beneath your sink, which cause water that flows down your drain to slowly and steadily leak out. www.duttonplumbing.com.

Do Horizontal Plumbing Vents Need To Be Sloped

And the answer is yes. Notice in the picture below how the horizontal portion of the plumbing vent has a slight grade to it.

Water vapor can condense inside vent pipes. Rainwater also enters portions of the venting system. And thats why horizontal vents should have a little slope on them. This slope drains any water vapor back into the drainage system .

Now I will mention something to my friends in the UPC. Unlike the IPC, the UPC will let you sneak by with a horizontal level vent . This assumes its above the FLR . But keep in mind, horizontal vents cannot have sags or any drops . And again thats UPC only, the IPC wants horizontal plumbing vents sloped.

Also, notice the bathroom sinks individual vent tees right into the toilets individual vent. Thats done with the appropriate sized sanitary tee thats upside down.

In the IPC use a 1.5 sanitary tee , or in the UPC use a 2x2x1.5 san tee to make this connection.

Then, this vent can terminate through the roof all on its own. Or in many cases, it can tee into the homes existing venting system.

Another important thing about plumbing vents

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Install P Trap Adapter

For a new sink installation youll typically have a piece of pipe sticking out of the wall. In order to connect the P trap youll need a trap adapter that needs to be glued onto the pipe in the wall.

Since my pipes are ABS Im using ABS cement. I simply swab the inside of the trap adapter with some cement and do the same for the outside of the drain, making sure to fully coat both surfaces, then push on the adapter, all the way in, giving it a slight twisting motion, roughly a quarter turn.

Install The Sink Drain Pipe System

The sink pipe system has four pipes, accordingly: the tailpiece, the waist arm, the p-trap , and the drainpipe to the wall cleanout. If you’re installing a double bowl sink, then a t-trap will be needed to join the tailpieces from the two bowls, per Keeney. To set this up, start by placing the washer through the tailpiece and push it up into your basket strainer. Secure this connection with a slip joint nut.

The next step is to connect your waist arm. Most times you will have to pre-cut this to fit into your pipe system, as noted by The Spruce. Before you throw out your old pipes, you can use the old waist arm as a guide to measuring the required length of your new waist arm. If the new waist arm is longer, use a PVC pipe cutter to cut off the extra length. Connect the waste arm to the tailpiece with a washer and slip joint nut and do the same for the p-trap to the drainpipe leading to the wall cleanout. Always remember that the p-trap must be connected to the last drain pipe .

When you’re done, ensure all nuts are tightly screwed on with the sink wrench and allow water to drain through the pipes for one minute. If there is no leakage, then your newly installed sink drain is good to go!

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What Causes The Leaking At The Connection

Ideally, when you have noticed the leak, the first thing to do should be to wipe everything down. Get things dry to either prevent or stop the damage caused by the water. After that, the next step is to try to figure out the issue at hand.

Generally speaking, there are four main reasons why you would be experiencing a leak at the connection. Those four reasons are:

Compression nut is worn. The connection point is held together by a compression nut. The nut can become worn or cracked over time, particularly at the threads. When that happens, water can get through at the point of connection. If the nut is noticeably damaged, it will need replacing.

Compression nut is loose. One of the most common reasons for a leak at the connection point is a loose nut. Try tightening the nut first and foremost. In most cases, that should be enough to stop the leaking. If that doesnt do it, you can move on to other troubleshooting methods.

Pipes are the wrong length. Even if the installation was done by a professional, that does not necessarily mean the job was done properly. Pipes can be the wrong size, putting pressure on the joint at the connection. And that is where the leak can occur.

P-trap clog. When there are clogs in your drain pipe, it can put extra pressure on the joints and pipes at the connection point. If your sink is having issues draining, be on the lookout for leaks as well as they often come in tandem.

Connect The Drain Trap

How to Connect a Kitchen Sink Drain Pipes with a P-Trap

The drain trap assembly includes a U-shaped trap bend and a J-shaped trap arm. The trap bend fits onto the bottom of the tailpiece tee fitting, while the trap arm extends into the drain outlet in the wall.

Assemble the trap bend and trap arm together loosely with a slip nut and washer. Slide a slip nut and washer onto the straight end of the trap arm. Push the trap bend up into the tee fitting on the tailpiece while sliding the trap arm into the drain outlet at the wall.

Adjust the trap pieces as needed to create the most direct path from the sink to the drain outlet. Make sure the trap arm has a slight downward angle toward the drain outlet.

Confirm that the continuous waste pipe and the trap arm slope slightly downward in the direction of the water flow, then check all of the drain connections to make sure they are tight.

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Should I Diy A Sink Drain Rough

For those with plumbing experience, you can DIY a sink drain rough-in, however, many will need the help of a professional to make sure your sink drain is set up correctly. Depending on where you live, you may need a permit and/or a licensed plumber on the job to pass inspection. It is always a good idea to check the building codes in your area before you start a home improvement project.

Here are some reasons it can be a good idea to pull in a licensed plumber for the job:

How Do You Connect Metal Pipes Under Sink

0:122:09How to Connect a Plastic Sink Drain Pipe to a Metal Pipe Coming Out ofYouTubeStart of suggested clipEnd of suggested clipThis right here is the key to hooking it up going through the wall. This is a flexible pipe. That weMoreThis right here is the key to hooking it up going through the wall. This is a flexible pipe. That we can hook up straight to our line right here. So we’ll take it and tighten it down to our. Line. www.youtube.com.

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How To Install A Vent On A Bathroom Sink

Set up the p-trap with the extension of the pipe previously set under the sink.
Fix the p-trap with cement or PVC glue.
Cut the drainpipe in the recommended length.
Join it with the p-trap and fix them with glue or cement.
Get a sanitary tee and attach the pipe with the middle leg of the tee.
Again, use the glue to fix them.

In Cold Weather Climates Plumbing Vents Need To Be Increased In Size Before Extending Out Through The Roof

This increase prevents the vent from closing due to frost . Check your local code for the appropriate size but usually, its 3 inches. This increase should also be made within the buildings thermal envelope. Or in other words, within the heated portion of your home. Again check your local code.

So that wraps us this article.

And maybe your wondering:

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To Add A Plumbing Cleanout Youll Need Two Additional Fittings:

A 3 cleanout adapter

And a 3 cleanout plug

The cleanout adapter glues right into the inlet of the combo. And provides a convenient point of access to rod the drain in case of a backup.

Two 45s

Lets move downstream into this drainage system.

In the plumbing diagram below, notice how the bathrooms 3-inch drain wyes right into the building drain.

Thats just a 3-inch wye . You could also use a 3-inch combo for this connection.

Now that you have a good handle on this bathrooms drainage system,

Lets switch gears and talk about

Lower The Drain Outlet If Necessary

If you find that the existing drain outlet is not low enough to accommodate the depth of the new sink, you will need to open the wall and lower the position of the sanitary tee connecting to the drain pipe in the wall. This can be a somewhat complicated job that requires cutting away the back of the cabinet and the wall surface.

Our example is a case in pointthe new sink left insufficient room for connecting a standard drain assembly to the drain outlet in the wall . So, the sanitary tee fitting serving as the drain outlet has been lowered . Keep in mind that the drain height must leave enough room for removing the trap and cleaning it out.

If you need to lower the sanitary tee in the branch drain, it is a good idea to wait until the other parts of the drain are test-fitted before gluing and securing the fittings permanently. Leaving the fittings loose will allow you some room for adjustment.

Before continuing to the next steps, remove the old sink and install the new sink in the countertop. Our installation will include a double-basin sink with a garbage disposal fitted to the right basin.

The Spruce / Kevin Norris

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Installing The Trap On The Waste Line

1Screw the J-pipe onto the trap arm to make the P-trap. Hold the J-pipe so the openings point up and the shorter side is on the right side. Position the angled opening of the trap arm over the short end of the J-pipe so the threadings line up. Screw the plastic nut on the trap arm loosely so the J-pipe can swivel around without falling out.XResearch source

Avoid tightly screwing the pipes together yet since you may need to adjust the angle of the J-pipe later on.

Do not apply pipe glue or cement around the threadings on any pipe connections since you wont be able to unscrew them. If you use glue, then you will need to saw the pipes whenever you make repairs.

2Slide a slip nut and washer onto the trap arm so the threading faces out. Take one of the plastic slip nuts from the P-trap kit and position it over the straight end of the trap arm. Make sure the threadings on the nut point toward the straight end. Then slide a tapered washer onto the pipe so the tapered side points toward the end of the pipe. Slide them about 2 inches down the pipes length.XResearch source

If you put the washers on with the tapered side facing in, then the pipes may leak when water runs through them.

Variation: If the inner diameter of the drain and the waste pipe were the same, use a flanged washer instead. Put the larger end of the flange inside of the trap arm so the wider end is flush with the pipe.

Avoid cutting the pipe at an angle, or else it will not fit properly and could cause leaks.

What Are The Materials Required For Connecting Bathroom Sink Drain

How to Connect a Bathroom Sink Drain

Plumbers putty

It would also be good to master that

A preliminary test fit, measurements, and making the cuts are done before finalizing the installation.
Gaskets and a slip washer are always placed with the bevel facing the two ends or the connection joint.
The fittings of the plastic P-trap should be hand tightened however, if theres any leak in one of the connections, you can carefully use adjustable pliers to tighten them more.
For the metal P-trap connections, use pliers to tighten them up.
When tightening the filter, ensure that the tailpiece hole faces the wall if your sink has a pop-up stopper.
If the pipes enter the compression fittings at an angle, they may not work correctly.
If youre replacing a damaged drainpipe, make sure that you buy it from the same manufacturer, or you buy one that can fit into the sinks base opening and the drain stub on the wall.

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A Guide To Connecting 1

To connect a 1-1/4 tailpiece to a 1-1/2 drain you will need to get a slip nut that measures 1-1/2 × 1-1/4 and a washer. This will fit both the sizes of the drain and tailpiece.

A 1-1/2 trap adapter can also be used on the pipe out of the wall. Adapters will help prevent water from leaking down from the main sewer line into the sink.

Metallic trap adapters are used in metallic pipes while plastic trap adapters are used in plastic pipes. The 1-1/2 metal trap adapter is inserted into the drain and tightened using stainless steel clamps that are on the adapter.

These adapters instantly create a sanitary seal that is leakproof. The 1-1-4 tailpiece can then be connected to the other side of the trap adapter.

For plastic traps, adapters glue will be needed to seal them to the drain. Make sure that the drainpipe is smooth and do a dry fit to confirm if the trap adapter fits perfectly.

Smear some glue on the outside of the drain and the inside of the adapter. Insert the adapter on the drain and hold it up until the glue reacts and sticks the two together.

Use a washer to insert the pipe from the tailpiece to the other end of the adapter. Read more about how to install joint washers in plumbing and sink pipe joints.

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Replacing The Drain Pipe

The new pipe should be the same internal diameter and length as the old pipe. This ensures that the drain will function correctly. When connecting the new pipe to an existing drain pipe, place rubber couplings on either end of the existing pipe loosening the steel bands will help you do this. You can also ease the steel bands on the opposite side of the couplings, ready to receive the new PVC pipe. You can use a flat screwdriver for this, but you can use a 5/16 inch socket if you have one too.

If you are also installing a new tailpiece and P-trap, install all of this before the pipework. Once this is installed, you can take accurate measurements for the rest of the system.

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How Much Does It Cost To Replace A Sink Drain Pipe

Replacing a sink drain pipe can cost from $100 $350 when a professional comes in to do the work. If you replace the pipework yourself, it will cost around $30 $50 at most for the pipe, fixings and PVC cement, and it will take a few hours to complete. As the material cost is so cheap, it is well worth investing in a multi-tool for this project. You can use it to cut the drywall and the pipe in this project alone. However, its uses around the home are nearly limitless.