What is the proper height for a bathtub vent?

Answer 1

The proper height for any vent of any fixture is outside the building mostly through the roof and the height above the roof depends on the average snowfall. In my state since we get a lot of snow the minimum height is 18" and it must be 3" diameter or bigger pipe size. The proper height for a vent going vertical to horizontal or to tie into another vent is 6" inches or more above the fixture flood plain. example -> if your tying together a tub vent and a toilet vent and your toilet flood plain is 14" above floor then you can tie the vents together at 20" or higher above the floor. When I run my vents horizontally I usually will run them at 58" or higher because most electricians put their electrical boxes around 48" above the floor.

The proper location of ANY Vent is above the flood level of the fixture ( not the over flow) and the vent terminal should be 4" to prevent hoarfrost as some lax codes to allow 3" which can be closed with frost.The terminal should terminate 7 Ft above the roofing surface if the roof is used for other then weather protection and some codes do allow 24" above the roof depending on application. The key to proper venting is to have the vent pitching up from the fixture so any moisture from the vapor will drain back to the fixture drain vbeing served