Thru roof stainless duravent chimney how much exposed before enclosing?

[greythorn3]

this is a ? just out of curiosity,

If you have a chimney like duravent how many feet do you allow it to go above the roof into the outside air before you think about enclosing it to help draft?

i noticed some peoples chimneys on top their houses have a little box built around them that goes to about 2" from the cap even if its a thru the roof install..

last chimney i installed i left 5 feet sticking out above the roof and never seem to have a draft problem.

is it just for looks mostly to enclose it? when its a thru the roof install that is, i can see why it helps with a thru the wall one for sure tho.

 

[SteveKG]

I don't have Duravent but Metalbestos, which I figure is about the same thing. None of my chimney pipes is enclosed. The shortest [from the roof to the cap] is 10 ft. and the highest 16 ft. I have always assumed that some enclose them simply for looks. Personally, I think the bare stainless pipe looks fine, so.....

 

[summit]

If heat loss on the vent is a concern, I would say anything over 5'. My metalbestos sticks up about 4' above the roof, and the last 1' or so is usually where any sticky bits seem to stay... last part of the chimney so it's obviously the coldest, things condense more toward the cap.

 

[Fsappo]

I also would suggest anything over 5 or 6 feet being enclosed. I'll normally tell the customer to burn the stove. If everything works great, spend the money on enclosing it if they really just want to pretty it up

 

[Wood Heat Stoves]

You don't need to enclose it, but it might help your draft a little if you did. Normally you would enclose it to a few inches below the top of the chimney and use a chase top which you can have made at a local sheet metal shop.

 

[begreen]

Depends on the climate. We have about 7ft exposed and it has not been an issue at all, but our winter temps are generally milder. In a snowy, cold climate, it can be more of an issue. Besides cooling, you also want to be sure to have a brace on the flue pipe once it reaches 5 ft high. A cricket to divert the snow is also a good idea if the pipe penetrates the roof on the low side. Regardless, all chimneys must extend a minimum of 3 feet above the roof surface and 2 feet higher than any part of the building within 10 feet.

 

[greythorn3]

thats what i figured it was mostly for looks, but i like that look of the stainless pipe the best, its almost invisable when it refects off the clouds and trees. really a neat thing to look at.