Home Improvements

[Fred Hargis]

Can a kitchen range vent be exhausted straight up through the roof? I don't think I've ever seen this, and speculate that the mess on the roof top may be one of the reasons. In our new house, there is no exhaust fan, just a microwave fan.  I would like to install an exhaust, but the design of the house and location of the range limits me to a roof discharge.

[RussBoyd]

Check your local code Fred, but here, it is fine. It does have to be a metal duct and does have to be vented to an actual vent. They used to use dryer hose and just put it near a vent. What little grease that might get into the vent wouldn't ever make it to the roof anyway (too heavy).

[TxMoose.]

Fred,

That is how my kitchen exhaust fan is. No problems.

TxMoose

[dad4taylor]

You can do it in my jurisdiction and I can't think of any reason why any jurisdiction would prohibit it.  Where I live it is the preferred way.  I agree that it needs to be real a "real" metal vent, none of that flexible dryer vent or plastic flexible stuff.  Venting through a roof seems daunting the first time you do it.  If the roof is asphalt or composition though it is a piece of cake.  Look at the other vents on the roof and you'll see how it's done.  If it's tile, or mebrane or tar or something else then it's not a job for you.  Good luck.

[monfre]

I think the national building codes will require you to vent wither thru the roof deck or side wall, and must be vented using metal or hard duct and should be of the 6" diameter and should also be atleast 250-300 CFM's for exhaust. If it were up to me I would use the sidewall if at all possible and also be sure to include a backdraft damper to keep the cold air form dropping down into the kitchen when the exhaust fans is not being used. And don't forget to have the exhaust fan interlocked with either your furnace to bring in makeup air when the exhaust fan is in operation otherwise your just going to suck out the conditioned, heated air from the kitchen and cause your house to go into negative pressure which can cause backdrafting for any and all appliances that operate on a pilot light.