How to properly relocate vent pipes in your bathroom

I live where it can get very cold and they say moving the vent pipes can be a problem. Do you know anything about plumbing? Can the vent pipes be moved, yes or no? Can I just lock it under the floor?

And what about moving wires and cables? Can that be achieved? What is moving all of these utilities about? – Susanne B., Minneapolis

A: Many do-it-yourselfers experienced this moment at some point in their renovation escapades. You know, when they cheerfully start tearing down a wall and finding all sorts of unexpected things going up through and between the mullions.

The quick answer for Suzanne is that the vent pipes can be moved. I can say this with considerable authority, having been a master plumber since I was 29 years old. The important question is: how easy will it be to lay the pipes?

This question can only be answered by visiting the construction site to see what framing is in the way and what additional demolition work needs to be done to create a path through which the vent pipes can drain any condensate back into the drainage portion of the plumbing System. According to local regulations, the vent pipes may need to be routed in certain walls. That is up to your local inspector.

Never close ventilation pipes. These pipes are important because they deliver air into the piping system. Most people think that the ventilation pipe on top of the roof is like a factory chimney that sucks out smoke. Vent pipes work in reverse order. They deliver air into the system every time you flush a toilet, drain a sink, or run water into a faucet. The moving water not only pushes air in front of it when it enters a septic tank or sewer, it can also create a vacuum when a gush of water passes a drain branch within the system.

Vent pipes must be installed like normal drain pipes. They must be sloped so that any condensation that forms in the pipes can gravity drain into the piping system on its way to the septic tank or sewer. The same condensation can be a bothersome problem in cold climates as hoarfrost can clog a vent pipe. Because of this, in very cold climates, the main vent stack is often full-size and has a 4-inch diameter pipe. The larger pipe size means that much more frost will have to form in order to throttle the air supply.

Vent pipes on exterior walls in cold climates should be positioned so that they are as far away from the cold exterior wall surface as possible. You want enough isolation space between the pipe and the outside wall that the pipe temperature is hopefully just above freezing point.

The electrical cabling can also be laid in the event of a renovation. Challenges can be significant, and the most important thing to remember is that neither you nor a worker should ever bury a junction box. If you need to create a splice to add additional wiring, the junction box needs to be visible. You can often accomplish this in a closet.

I always wrote a note and put a little drawing in the junction box of what had to be done to move the cable. Trust me when I say that a future electrician will love to read this note. It could help him diagnose a future problem within the circuit, as he would have no idea that remodeling work could have happened 50 years earlier.

Heating and cooling ducts are by far the most difficult to relocate. The size of the pipes and lines is the first challenge. The second, more sinister problem, is poor performance as additional fittings and plumbing must be added to make the change.

Adding a 90 degree bend to a typical heating or cooling duct line is the equivalent of adding 10 extra feet of pipe. The air flowing through a heating or cooling duct is very sensitive to additional friction caused by additional fittings or pipes. More friction means less conditioned air delivered to the room where it is needed.

Be sure to discuss this openly with your HVAC professional if the space served by the plumbing is currently not as comfortable in extremely hot or cold weather.

As you build a new home or large space, you can do yourself, your remodelers, and future homeowners a favor. Try to take as many photos as you can of all of the walls, ceilings, and floors in your new home or room before covering the utilities with drywall or insulation. Save these photos to a simple storage device like an SD card or a micro SD card. These are so very cheap and can take thousands of photos.

Put this memory card in a plastic bag and label it. Glue this pocket to the front or inner cover of the circuit breaker plate. You have no idea how precious these photos will be to someone in the future, and they will toast you over lunch or dinner that day!

Subscribe to Tim’s free newsletter and listen to his new podcasts. Go to: AsktheBuilder.com.

You might also like

Comments are closed.