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Vent pipes play a significant role in your plumbing system. In fact, they supply each of the fixtures in your home with air. This helps pressurize the system so that wastewater water can drain properly. For instance, each time you flush the toilet or fill your basins or tubs with water and then drain them, it uses the air in the vent pipes to force the wastewater down the system to the septic tank. However, without the vent pipes supplying the system with air, your fixtures would experience a slow drain.

Vent pipes run from the fixtures up to the attic where they connect to the roof vent pipe, which supplies the plumbing system with outside air. However, to function properly, they need to be installed properly. This basic guide on how to install plumbing vent, brought to you by master plumbers, will help you do that.

Step 1: Begin with a Full-Size Roof Vent Plumbing Pipe

For how to install plumbing vent in a new home, you’ll need to begin by installing a 4″ plumbing vent pipe in the attic that leaves the roof.

Vent pipes can fill with warm air, which can cause condensation inside the pipes. In colder temperatures, this condensation can freeze and clog the pipes with ice; however, since full-size pipes have more capacity, they are less likely to become clogged with frozen condensation.

Step 2: Transition to 3″ PVC Pipes

Once you have the full-size PVC roof vent pipe in place, simply transition to 3″ PVC piping for the rest of the main vent pipe system.

Begin by attaching the 3″ pipe to the full-size roof vent pipe. Next, run the 3″ piping across the ceiling of the attic down to the master bath, using a 90-degree bend and an even layer of cement glue to connect the PVC pipe and fittings.

If you are installing additional fixtures, such as second bathroom fixtures, a kitchen sink, or laundry room fixtures, simply tie a 2″ vent pipe into the 3″ vent pipe, using a 3″ by 2″ tee, which can be used to tie the fixtures into the vent system later.

From the master bath, continue the piping down under the floor, where it will tie into the main drain system.

When installing vent piping, it is important to install them with a fall to them. This allows condensation to drain from the pipes.

Step 3: Tying a Master Bathroom Sink into the Vent Pipe

To tie a master bathroom sink into the vent system, simply connect a 3 1/2″ Y with a 45-degree bend on it to the 3″ vent pipe. Afterward, install a 1 1/2″ branch arm for the bathroom sink.

To tie a tee into an existing plumbing line, first, mark the PVC pipe where you want to cut. Afterward, using a battery operated sawzall or a PVC cutter for a clean cut, cut into the pipe where you want the tee to go.

Position the tee in place to ensure it fits, and then remove the tee. Always install the tee upside down, so that the air comes down and into the bend.

Apply PVC primer to the exterior of both pipes and the inside of both of the in-line legs on the tee. However, don’t prime the angled in-line leg until you are ready to cement that section of the pipe.

Next, apply PVC cement to the primed fittings and pipes. Afterward, insert the tee securely in place. Hold the tee in place until it dries, about 5 seconds.

Lastly, install the branch arm into the last leg of the tee fitting.

Step 4: Tying the Master Bath Shower into the Vent Pipe

Using a 1 1/2 ” pipe, tie the shower line into the main drain located under the floor, via a 2″ by 1 1/2″ tee. Afterward, run the piping on up to the attic where you will tie it into the 3″ vent pipe that extends from the attic.

Step 5: Tying a Second Bathroom into the Vent Pipe

Using a 1 1/2″ pipe, tie the bathroom sink into the 2″ vent pipe that was installed in the attic earlier.

To attach the toilet to the system, you can simply tie into the same 1 1/2″ vent piping that comes down and supplies the second bathroom sink, using a tee and 1 1/2″ pipes.

For the tub and shower, you can also use a 1 1/2″ pipe to tie into the same 1 1/2″ pipe in the attic that supplies the sink and the toilet.

Step 6: Tying a Kitchen Sink into the Vent Pipe

On the outside wall of the kitchen sink, using a 1 1/2″ by 1 1/2″ by 2″ tee, tie into the vent system. Afterward, extend a 1 1/2″ pipe up to the attic and across the ceiling in a sloping motion to attach to the 2″ vent pipe that was installed earlier.

Meanwhile, use a 2″ pipe to tie into the main septic system under the floor. A 2″ stack is often recommended for kitchen sinks; it gives you extra capacity, so it is harder for the line to get clogged up.

Lastly, connect a 1 1/2″ branch arm to the tee, which will be used to connect the kitchen sink.

Step 7: Tying Laundry Room Fixtures into the Vent Pipe

Using a 1 1/2″ pipe, simply run the piping for the washing machine up to the attic. There it will tie into the same 2″ pipe that supplies the second bathroom and the kitchen sink.

Bottom Line

So there you have it, how to install plumbing vent in a nutshell. How to install plumbing vent may vary in layout, pipe sizes, and inclines. It depends on the particular design and building codes associated with your project.

However, the basic principles of how to install plumbing vent remain the same. This includes using a full-size vent pipe to attach to the roof, using 3″ piping for the main vent pipe system, using a 2″ stack for the kitchen sink, and installing the vent pipes in a fall to prevent condensation build up.

After implementing these steps how to install plumbing vent, please feel free to share your exciting journey.

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