I’m redoing my garage, where I have my Washer/dryer and water heater. I’m also redoing my garage roof – right now it has a bare OSB deck.<!—-> <!—->
I have a 2″ sewer line stack, a 4″ Water heater chimney stack, and the 4″ dryer vent, all within a very close area. Instead of making 3 small individual holes in the roof, I was considering making a single “Stack Hole” for all three. The larger hole would also have a single protective cover. I imagine the hole to be about 12″, with a ventilated stack cover. <!—->
My concerns are this – code compliance? Though the materials that are in close proximity are non-combustible (metal vent pipe), there is always a tiny amount of lint coming out of the dryer. Is this a concern if it exits where the water heater exhaust exits? <!—->
Also, is there regulation on vent/stack /exhaust location with regard to windows? My son’s 2nd story window would be about 5-6 feet away from this, and sit a little higher than the lip of the existing stacks. Do the stack heights need to be raised? <!—->
BTW, when the water heater is running, the uninsinuated exhaust pipe is not hot enough to burn flesh. It is not a high efficiency water heater either.<!—->
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Edited 4/29/2005 1:09 pm ET by xxPaulCPxx
Edited 4/29/2005 1:10 pm ET by xxPaulCPxx
Replies
I don't see the advantage.
If each is done separately, you can flash with standard off the shelf products that have a long history of proven performance.
If you group them through one hole, then you have to fabricate some kind of custom flashing that may or may not work.
If they were run together and I was bidding the roof job, I'd charge a lot more than if they were separate.
If they are already so close together that the separate flashings would interfere with each other, then I'd put a jog in a couple of them in the attic to spread them out.
Rich Beckman
Another day, another tool.
They are in close proximity to one another. Instead of using seperate 3 off the shelf flashing systems, and having 3 potential leak or other problem points, I'd like to use a single one that is big enough to encompas them all. It would also have a cleaner look.
Since they would all be covered by a single vented cover, I would no have to worry much about sealing up the holes internal of the larger opening. This is So Cal, where we get less rain anyway.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
"My son's 2nd story window would be about 5-6 feet away from this, and sit a little higher than the lip of the existing stacks. Do the stack heights need to be raised?" - No. Per the International Fuel Gas Code, "A mechanical draft venting system, excluding direct vent appliances, shall terminate at least 4 feet below, 4 feet horizontally from, or 1 foot above any door, operable window or gravity air inlet into any building."
Thanks for the details on that question, Timbo!Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Local building codes will answer your proximity questions.
As far as ganging the stacks together, it might be a bad idea.
Drier vents can have combustables, hot water vents may be higher temp than is safe - around here it is a no-no, no matter what.
Quality repairs for your home.
AaronR Construction
Vancouver, Canada
I would not put all three into a single covered roof vent.
If you have a back draft situation with the gravity drafted water heater then you have the possibility of drawing sewer gas into the building.
The W/H stack should be b-vent when it passes into the attic and through the roof, and it requires a 2" clearance from combustable materials. There are specific codes for the venting positions near windows/doors....as said before local codes prevail.
Venting dryers through the roof are the very last choice of venting positions. Horizontal runs are best, usually vented thru the wall. Use only aluminum rigid or semi rigid piping.
Spread them out on the roof, or line them up like soldiers.
Use stock flashings. It will be a whole lot quicker and they don't leak when applied in the standard manner. Probably a greater chance that your fabricated tri-vent will leak.
Paint the pipes the same color as the roof shingles.
Only you will notice the three little pipes on the roof. If anyone else notices, tell them they were driving too slow. ;>)
.............Iron Helix
57622.7 in reply to 57622.1
"If you have a back draft situation with the gravity drafted water heater then you have the possibility of drawing sewer gas into the building."
I hadn't considered the possibility of methane getting sucked down the pipe into the combustion area - good catch! That reason alone is enough to dismiss this idea.
As a side note, I never considered fabbing my own flashing. 10", 12", and even 14" prebuilt flashed round roof openings are readily available at a building supply store... you just need to look at those ugly attic ventalators! Of course, a brick faux chimeny could be cool too.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
If you really want to do it this way, my suggestion would be to build a louvred coupola on the garage roof that is big enough to allow you to bring all three units through one square hole in the roof deck. However, the point raised about unwanted gravity drafting of one exhaust product into a neighboring stack is well taken. You can (and should) put a flap-closer on the dryer vent. I don't think you can do the same for the HWH chimney, and I'm sure you can't for the drain vent.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
I did not mention that a down draft situation may also cause accummulation of carbon monoxide within the house.
If you use the cupola idea, remember that all three vents release large volumes of water vapor. Any enclosure will soon be be dripping with water/ice icicles....could be a greater problem than the three flashing issue.
If your local plumbing code permits the use of a "studor"(?) vent then you could cut off the vent pipe at the attic level and cap it with this "intake breather vent valve" to eleiminate one of the roof top vents.
Illinois code still does not permit "studor", but I see a lot of them installed. They can be purchased at the local big boxes and plumbing supply houses.
And once again...if you take the dryer vent out the wall then only the WH vent is exiting the roof!
...................Iron Helix