Range Hood Venting

[LongLook]

I'm in the process of buying a 17 year old house where the gas range has a range hood that vents into the attic space.  When the house was built this was within code but things change.  The home inspector says it should be vented and according to code it needs to exit on the roof or a sidewall.  The current owners ( and I as well) aren't too keen on adding another roof hole and a sidewall exit isn't possible.  Any thoughts on alternatives or just leave it as is?  I don't want to exit it on a soffit vent due to possible staining.

UPDATE: Original builder hired to vent through the roof. No evidence of any mold or grease build up from past use so I think the issue is resolved.

[fredhargis]

I'm hesitant to say this, but I'd leave it as is. It's bad practice and may violet some codes, but it's not that uncommon....at least around me. Venting the bath fans into the attic is common as well (and bad practice IMHO).

[harderhandyman]

Here's a picture that I took last year while blowing insulation into an attic, sorry for the poor quality picture.  You can see the range hood vents into the attic, and the staining/decay that it has caused on the underside of the roof.  The warm air introduced into the attic on a cold day produces moisture, not a good thing. 

   

[jteneyck]

I'm in the process of buying a 17 year old house where the gas range has a range hood that vents into the attic space.  When the house was built this was within code but things change.  The home inspector says it should be vented and according to code it needs to exit on the roof or a sidewall.  The current owners ( and I as well) aren't too keen on adding another roof hole and a sidewall exit isn't possible.  Any thoughts on alternatives or just leave it as is?  I don't want to exit it on a soffit vent due to possible staining.

One more roof penetration isn't going to hurt if it's done correctly.  Leaving things as they now are is going to cost more in the long run.  

John

[Splinter Puller]

I'm in the process of buying a 17 year old house where the gas range has a range hood that vents into the attic space.  When the house was built this was within code but things change.  The home inspector says it should be vented and according to code it needs to exit on the roof or a sidewall.  The current owners ( and I as well) aren't too keen on adding another roof hole and a sidewall exit isn't possible.  Any thoughts on alternatives or just leave it as is?  I don't want to exit it on a soffit vent due to possible staining.

I had mine exit the house by going out and dumping out the soffit at the eave.

[fredhargis]

So maybe look in the attic and see if there's any damage???

[srv52761]

Another option, charcoal filters for odor control, close the damper and recirculate to the kitchen.

If the hood can not be reconfigured in that manner have the homeowner replace with a ventless range hood or maybe even an over the range microwave. include it prior to purchase.

[MstrCarpenter]

My over the range microwave vents out the back to a 3-1/4" x 10" 90* then up the wall, thru the 2nd floor, continuing up thru the wall and into the attic to a 3-1/4" x 10" x 6" round 90* transition. From there it runs about 18' horizontally to a 6" (gable end) wall hood. I sealed the joints with foil tape and added some tek screws just in case. The vertical ducts are female up and the horizontal in the attic is pitched slightly down and has the males pointing outward. The 6" actually terminates outside of the siding and connects directly to the hood. When the fan is turned on high the damper is pinned in the open position. All of the smoke, odor, and condensation is contained/controlled until outside of the building envelope. Over ten years in with no maintenance required. If you use yours a lot the way it is; you may need new roof sheathing before you need new shingles.

[Robert Adams]

Always take what an inspector says with a grain of salt. They like to say all this stuff isn't done to code. Well yeah not to current code... Lots of stuff on all houses were code when they were built and no it doesn't mean you have to change it because it doesn't meet current code. Just one of my annoyances of inspectors. Anyway...


        This is one of those I don't care what anything says. Cut a hole in the roof and run that vent out the roof. That fan is blowing lots of grease and crud into the attic. You don't want that up there. 

 
          Now in a northern climate you will also have issues with the excess moisture that is also being pumped into the attic. Cooking produces lots of water vapor. As for bathroom vents for me it depends on climate. In a cold climate yeah that moisture being added to the attic is an issue. In a southern cooling climate it doesn't bother me as much as it's always humid year round and actually that little bit of cool air being pushed into the attic isn't too bad of a thing unless your attic is super sealed with no ventilation then you will already have the issue of the hot air from the attic pushing down into the walls and the house.

[Snipe Hunter]

One more roof penetration isn't going to hurt if it's done correctly.  Leaving things as they now are is going to cost more in the long run.  

John

+1

17 years ago, the national code required it to vent outside. The code may not have been adopted locally but it should have been. Even if it did meet code when it was originally built, most contractors didn't do it. The builder cut corners. If they cut corners there, they may have cut corners venting the attic too. If the attic isn't properly vented, it could compound the problem. It's not a an expensive or difficult fix. Getting mold out of the attic, fixing rotted roof sheathing are much more expensive repairs.