How To Look At A House

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Do plumbing vent pipes have to go through the roof by code?

Monday, February 7, 2022

The International Residential Code requires a minimum of one vent to the "outdoor open air" per residence (IRC P3114.7). The rest of the plumbing fixtures can be vented by an air admittance valve, island vent, or combination waste and vent. 

    Although the plumbing vent that terminates in outside air usually runs through the roof, the IRC allows other options—such as running up an outside wall—as long as the termination is away from doors, operable windows, any soffit vents, and a minimum of ten feet above ground. For full details, go to What are the code requirements for plumbing vent terminations?

    To learn more about two of th venting alternatives, go to Is an air admittance valve (AAV) legal by code? and What is a "combination waste and vent" in a plumbing system?  

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Here’s links to a collection of some of our other blog posts about PLUMBING DRAINS AND TRAPS:

What are the pipes on my roof?

• What types of plumbing traps are illegal by code? 

What are the code requirements for layout of drain piping under sinks?

Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

Why is it a problem when a trap under a sink is installed backwards? 

 What is the difference between a vent stack and a stack vent? 

• Why is garbage disposal not allowed at a combination waste and vent (CW&V) under a sink?

What is a building trap?

What is an indirect waste receptor? 

What is the difference between water pipe and sewage (waste) pipe? 

How can I tell if a house is connected to a septic tank system or sewer? 

Why is there a flexible accordion pipe under the sink? 

How do I get rid of the sewer gas smell in my house?  

Is a sink required to have a drain stopper? 

• Can a laundry sink drain be installed without a trap under it? 

• What is a drum trap at a plumbing drain?

• Can a dishwasher drain hose be connected after the sink trap (to the trap arm)? 

How far away from the sink can I install a dishwasher? 

• What is a double trap in plumbing? 

• Can two sinks share a trap? 

• Does a home inspector check sewer lines underground?  

   Visit our PLUMBING DRAINS AND TRAPS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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