Expert: Dan Griffin - 4/29/2010

Question
I have two baths equipped with exhaust vents going out a tile roof.  I want to add a vent for my kitchen gas range.  The back of the range sets against an interior wall, I would have to 90* towards the back exterior wall about 10 feet.  Is there any way I can splice into the existing bath vent at its highest point then I could go straight up the ceiling.

Answer
Glen, I'm not aware of any code restrictions that would prevent combining vent stacks.  I do suggest you contact a local inspector or even a friendly constractor - if you don't get a good answer, I will check with one of my mechanical friends.  The prime consideration is distance and motor power.  All exhausts - dryers, vent fans, etc - have a written limit on length of pipe with major deductions of the distance for fittings and restrictions.  Commerical kitchen exhausts have to have fire supprssion and inspection openings.  All kitchen exhausts will require periodic inspection with cleaning and/or replacement.  A horizontal run is subject to lots of grease catching.  Why not add new metal duct parallel to what you are wanting to tie onto?