Anonymous wrote:How may not allow it

*Hoa

How may not allow it

Hey pp - look at a joist table. They are not always 16 on center. Same with walls. It depends on the spans, framing method, materials, loads, etc.

In between the ceiling of one floor and the floor of the one above are pieces of wood called joists. The joists are usually spaced every 16 inches, and run the short dimension of the building.

You can't cut a hole in a joist to run a duct. If you can run a duct parallel to the joists without having to cross one to an outside wall, you can run it in that space. If you have to cross joists, you have to run the duct below the joists.

Sometimes you can use the space above cabinets, or the back of cabinets or the back of a closet. For a decent kitchen exhaust fan you're looking at a duct at least 6" in diameter and possibly 8".

OP; thanks for replies. Unfortunately, most of the townhouse layouts I've seen usually do not have the stove at an exterior wall. A couple may be near enough to go through cabinets, thanks for that suggestion!

Anonymous wrote:It is like HVAC ducting. But is the cooktop on an exterior wall? If so, it may be pretty manageable to go straight out through the wall. You'll need to pull an electrical line from somewhere for the fan, but otherwise not too bad.

This. We did this at our house. The contractor said it was easy to do because the stove is on an outside wall.

It is so often overlooked, and may very well be quite complicated (and $$$) to do after the initial build.

If it's near an exterior wall, it's easy, but if there are not soffits, you'll have to go through a cabinet or two and lose that space.

It is like HVAC ducting. But is the cooktop on an exterior wall? If so, it may be pretty manageable to go straight out through the wall. You'll need to pull an electrical line from somewhere for the fan, but otherwise not too bad.

I'm sure this is home specific but... I'm interested in several townhomes. They have electric stoves (that's fine, I'll go induction) and often don't have proper exhausts above the stoves (just the grease filter style that vents air back into room after cleaning, or the same in downdraft version). We cook a lot, so this feels like a bit of a dealbreaker (the kitchen gets smokey even with an exhaust in our current place when, eg, searing steaks).

Is this kind of like HVAC ducting? IE, unless you are doing a major reno and ripping out walls, it's hard to retrofit an exhaust duct in?