If you’ve removed a sink in the bathroom or kitchen, you likely have an old drainpipe. You can remove it with very little effort.
In most cases, removing an old sink drainpipe means cutting the pipe at the access to the drain. From there, you can take it out of the wall and cap it. Then, you’ll want to close the hole in the wall. That’s it! Your drainpipe is gone.
How to Remove an Old Sink Pipe from Wall: 5 Easy Steps
Removing a sink pipe from a wall is normally relatively easy. However, it changes in complexity depending on the installation and setup. These 5 steps will walk you through every part of it. However, you may have to adjust based on where your sink is.
Find where the drainpipe connects to the sewage
Follow the drainpipe to where it connects with the main line. This might be in your crawlspace if your sink is on the ground floor. It might also be just under the floor. In either case, you’ll have to get at least a bit dirty. That might mean going into the crawlspace with a mask, gloves, and eyewear protection. It might also mean simply taking up a few floorboards in your kitchen or bathroom.
Once you find the connection, mark it and measure the circumference of the pipe at the mark where you want to cut. An inch or two out from the main pipe is usually the best place to cut.
Check the vent pipe
All drains use a vent pipe to let air out of the system. This air vent prevents backwards pressure from the sewer, directs air bubbles up and out of your home, and otherwise keeps your drains from smelling. The vent pipe is normally located in the wall. It also normally goes from the drain to connect to a central vent pipe that goes to the roof. In some rare instances, it might vent directly into a wall. You want to find this pipe on the vent and trace it to where it connects with the main pipe or to where it exits the home.
To do so, you probably want to check the main vent pipe first. This is normally relatively accessible via the attic or via a storage closet. However, you might have to remove drywall to access it. Once you do find it, check how it’s connected. If you have a pipe Y marking the sink to another pipe, you want to remove the Y and put in a single connector instead. You’ll have to buy that. Alternatively, you could leave the Y in and simply cap it. In that case, you can cut the vent pipe a few inches from where it meets the main pipe and put a cap on. That will allow you to use the same Y at another point and for another drain.
Buy pipe caps in an appropriate size
Take your measurements to the hardware store and purchase suitable end caps, in the same material. You’ll also want to ensure you have PVC pipe cement, a hacksaw, gloves, and eye protection. If you don’t have them, buy them at this point in time.
Cut the pipe
You’ll want to cut the pipe in three or four places depending on how your pipe drain is set up. The first cut should be where you made the first mark, a few inches from where the pipe meets the main drain. Use a fine-toothed hacksaw and use long, downward-facing strokes for the best efficiency. You’ll want to cap this immediately. Use pipe glue to secure the cap and then press it firmly onto the cut. Most pipe glue has instructions on the bottle. However, if you’re in an enclosed space, use eye protection and wear gloves. Use the included applicator to coat the full contact surface of the cap with glue. Then, dust off and blow any loose PVC off the pipe. Wait a minute for your PVC to start to set. Then, press it down and leave it to dry.
You’ll want to make the second cut at the main vent. Repeat the same process. Then, go back to the sink. You may have to remove the drywall or cut a hole. However, you can try to remove it without doing so. Here, you’ll want to pull the pipe out as far as it will go, cut it behind the U bend, and then pull it out further. If you continue repeating this process, you’ll have the whole thing out.
However, chances are, you do have to cut a hole in the wall. Then you can cut the vent pipe away from the main pipe. You’ll also want to cut the wall pipe at any bends, so that it can be removed through the hole.
Pull the pipe pieces out
Pull the remaining pieces of pipe out of the wall. From there, all you have to do is patch the wall back up. If you have trouble removing the pipe, you can always trace the problem back to further bends in the pipe. This might mean making more holes in the wall. However, worst case scenario, there’s nothing wrong with leaving a bit of empty pipe in the wall.
How to Replace Bathroom Sink Drain Pipe With A new one in Wall
If you just want to replace your old drain pipe with a new one, in the same place, you can take many of the same steps you did with the cutting the old one out. However, you’ll buy pipe connectors and not caps.
Measure the Length of the Pipe
Measure your pipe to see how long it is, how many turns it takes, and the diameter. You want to have a very good idea of how the pipe fits into and through the wall. Check the length on each section of pipe. Assess how many elbows you’ll need. Then, buy a pipe connector, the lengths of pipe you’ll need, and any tools you’ll need.
Importantly, you probably don’t have to replace the pipe vent. Instead, you can connect it to the new pipe. Why? It’s very unlikely your vent pipe is corroded, damaged, or clogged. Replacing it would be wasted effort.
Go the hardware store and buy replacement PVC or ABC pipe depending on what you have under your skin. If you currently have metal fittings, you might want to buy new metal fittings. However, in most cases, PVC is just fine, unless you’re connecting it to hot water. However, this is very unlikely for a drain pipe. PVC is cheaper, easier to replace, and less likely to corrode. When in doubt, you can always contact a plumber for advice.
Cut the Old Pipe
Cut the old pipe at the front and end of the pipe. Follow up with making more cuts at any joints in the pipe. You may have to cut holes in your walls. However, most people prefer to remove the drywall panel, as that’s easier to repair. Pull the old pipe out. Take the time now to match the old pipe up to the new pipe, so you can cut the new pipe in the appropriate sizes.
Fit the New Pieces Together
Fit the new pieces together, starting with the main sewage drain. Use PVC glue at each connection. In some cases, you’ll want to fit a connection together and then fit pipe into the wall so that it can fit, before you glue it in. Always use PVC glue on connections.
Your main concern should be getting the pipe through the wall in the same way. That’s especially true if someone has drilled through wall studs to place the pipe, rather than running it entirely in the crawlspace.
4 Causes of Corroded Drain Pipe in Wall
If your drain pipes are corroded, it might be impossible to pinpoint exactly why. However, there are plenty of reasons your pipes might be corroded.
If your pipes are corroded, chances are, they are very old. True corrosion normally only impacts metal pipes. Any metal pipes in a drainage system are likely very old. As in, pre 1980s at best.
Air in the Water
If you use very hot water, it could be heavily oxidized. That means that as much as 35% of the water could consist of air bubbles. This exposes pipes to oxidation and could cause rust and corrosion in metal fittings and pipes. The only solution is to replace the metal pipes for PVC – unless the water is too hot.
Regions with heavily acidic water struggle with pipe corrosion. Often, this water is far from drinkable. You can resolve the problem by filtering water. However, that can get expensive for your full house. On the other hand, it might be cheaper than periodically replacing your plumbing.
Overuse of Drain Cleaners
Heavy use of drain cleaners can cause corrosion in PVC and ABC pipes. Why? Most drains are not built for consistent use of heavy chemical irritants. If you frequently have drain issues, use a snake or an auger instead.
Replacing a drain pipe is a lot of work. Chances are, you still have questions. Hopefully, this FAQ will help.
How much does it cost to replace main drain pipe?
In most cases, you can expect to pay $0.75-$30 per linear foot of drain pipe. Plus, you’ll have to pay for labor. That ranges between $15 and $65 per hour, per person. With most main drain pipe replacements taking anywhere from 4-60+ hours of steady work, costs can vary. Usually your biggest considerations depend on original material, getting the old pipe out, and wall or flooring material. E.g., if you have wood floorboards, it’s a lot cheaper to remove than taking out a cement wall.
Is pipe relining worth it?
Pipe relining is a very long-term solution to fixing your pipes. In most cases, pipe relining means inserting a layer of resin inside the existing pipes. You essentially create a second pipe inside your pipe. However, this solution is not suitable for smaller diameter pipes. Otherwise, pipe relining is faster, cheaper, and more durable than most new pipes.
Are blocked pipes covered by insurance?
In most cases, blocked pipes are covered by your insurance. However, if your pipes are old and corroded or damage is caused by cracking, they likely won’t be covered. You’ll want to call your individual insurance company for more details.
Removing old rain pipes is often relatively easy. However, you will have to do so with care. You’ll also want to ensure that you use appropriate mouth and nose protection when using pipe cement in enclosed spaces. Finally, depending on what you want to do with the drain, you will need either caps or new connections to integrate ventilation into the new drain pipe.