Can you use a single wall 8” stovepipe through a metal ceiling

[Swingpure]

Last year I had a 6” stovepipe that went out the back of my cinderblock evaporator and ran outside of my metal roof. This year I will be having a base stack with an 8” stovepipe that will go through the metal roof. The only flammable items near by would be the trusses that would be 8” away from the pipe.

Can I have a single wall pipe go through the metal roofing, or do I have to use a double wall section of stove pipe?

If I am allowed to use a single wall stove pipe, is simple flashing enough on top of the roof?

A single 3 foot section of double walled 8” stovepipe costs almost as much the base stack itself.

Thanks for any advice you can give.

[aamyotte]

I had a small fire from a 8" single wall chimney with wood 12" away from the chimney. I was using a blower so the stack temp was higher than natural draft.
It would be better to use double wall chimney.

[wvfdc4]

Rule of thumb from a fire department perspective (inside a house) is that single wall needs a 16" clearance to combustibles. Insulated double wall is a 2" clearance. Not sure if that is gospel in a structure like yours, but that is my $.02

[Pdiamond]

I believe you should check and go with your local fire codes.

[Z/MAN]

I have single wall going through the metal roof. I have a 10" stack and my rafters are 16" on center. I have my rafters insulated with arch board and never had a problem. My base stack glows red at near 2000 degrees. I'm not telling you to do the same, just telling you it works for me.

[Swingpure]

I have single wall going through the metal roof. I have a 10" stack and my rafters are 16" on center. I have my rafters insulated with arch board and never had a problem. My base stack glows red at near 2000 degrees. I'm not telling you to do the same, just telling you it works for me.

What do you use on the top of the roof to keep the rain out?

[Z/MAN]

What do you use on the top of the roof to keep the rain out?

I actually just cut the hole and put the pipe through. Very tightly. It leaks during the season and when the season is over I run a bead of silicone around the pipe sealing it for the summer. My shelter is just a roof coming off the side of my garage that has some temporary walls added. It has evolved over the years to a decent setup. Can't find the time to build a real Sugar Shack.

[ebliese]

I have an 8" single walled pipe going through a metal roof. I used a roof jack (flashing) and a storm collar. So far, I haven't found any sealant for the storm collar capable of sustained, high heat so my stack leaks (which I am working on fixing). I have about 18" clearance to combustibles. This I accomplished by removing a section of purlin between two rafters. Even then, I covered the structural lumber with insulation. My stack temps generally fall between 900 and 1200*F.

If you stick with single walled pipe-DO NOT wrap insulation around the pipe. It will catch fire. Don't ask me how I know. The pipe needs air.

If you buy double walled pipe-yes, it would be expensive, but not as expensive as building a new sugar shack.

As others have referenced, check your codes.

[aamyotte]

Interesting detail about wrapping the pipe with insulation and it burning. Did you use regular fiberglass insulation?


I have an 8" single walled pipe going through a metal roof. I used a roof jack (flashing) and a storm collar. So far, I haven't found any sealant for the storm collar capable of sustained, high heat so my stack leaks (which I am working on fixing). I have about 18" clearance to combustibles. This I accomplished by removing a section of purlin between two rafters. Even then, I covered the structural lumber with insulation. My stack temps generally fall between 900 and 1200*F.

If you stick with single walled pipe-DO NOT wrap insulation around the pipe. It will catch fire. Don't ask me how I know. The pipe needs air.

If you buy double walled pipe-yes, it would be expensive, but not as expensive as building a new sugar shack.

As others have referenced, check your codes.

[Swingpure]

Thanks for all of the advice. I will get the double wall stove pipe. I found a place where I can get 36” for $209 Cdn and may have a less expensive source as well.

Likely a 3 foot section would do me, to get past anything combustible, and to make it through the boot, because the combustible area is only 7” thick. If I want a 12’ long stove pipe, I would still have to add another foot or so of pipe.

[nhdog]

i don't see why you don't think about using a section of insulated stove pipe. the cost is about the same as the double wall pipe you are talking about. the requirement is only 2'' from something that will burn plus you will be able to get the roof jack (flashing) and storm collar to fit, no fear of fire or leaking. if you don't get stainless you will be replacing it every so often (more $). i ran single stainless single pipe up from the evap then went to insulated up through the roof with insulated pipe. no ,leaks, no replacement problems, no fear of fire, and my roof is wood and shingle

[Swingpure]

i don't see why you don't think about using a section of insulated stove pipe. the cost is about the same as the double wall pipe you are talking about. the requirement is only 2'' from something that will burn plus you will be able to get the roof jack (flashing) and storm collar to fit, no fear of fire or leaking. if you don't get stainless you will be replacing it every so often (more $). i ran single stainless single pipe up from the evap then went to insulated up through the roof with insulated pipe. no ,leaks, no replacement problems, no fear of fire, and my roof is wood and shingle

Thanks when I Google insulated stove pipe, it comes as the same as double wall stove pipe. Is there a difference?

[nhdog]

you will find that most all insulated stove pipe only require 2'' of clearance from burnable material. you can use regular single wall pipe from your evap then there is an adapter that allows you to add the insulated pipe up through the roof. if you would like pictures p.m. me your email and i can send them

[ebliese]

Interesting detail about wrapping the pipe with insulation and it burning. Did you use regular fiberglass insulation?

I used ceramic fire blanket left over from bricking the arch. Much later on, the company I bought my evaporator from also mentioned to not wrap the base stack with insulation as it needs the air to avoid overheating. I suspect this was the problem I had, even though I only wrapped the pipe where it went through the roof.

[Swingpure]

I went to a local hardware store to talk stovepipes and to a local fireplace store, and talked to two friends and also talked to the gentleman who I will be getting the base stack from. Confusing information, but I think I learnt a few things and know what I want to do, almost.

I learnt that at least in our area, what you call double wall stove pipe is different from chimney pipe. Double wall is for inside the building and chimney pipe is for outdoors, but could be used indoors as well.

You have to support the chimney pipe.

What is not clear to me, some say the single wall pipe can fit directly into the chimney pipe and others say you need an adapter that is made for a particular manufacturers chimney pipe.

The gentleman who I am buying the base stack from says the single pipe can go directly into the chimney pipe, and he may have some reasonably priced chimney pipe, so I may just get it all from him.

I will have the base stack, then add on the chimney pipe. I will build a redneck support for the chimney pipe. And it will go through a fairly tight hole in the metal roof and I will have a storm collar for the chimney pipe.

[wobbletop]

I found the Selkirk product line the cheapest when I was looking. You can also call their technical help line to get information on your install.

I also found their manual helpful. https://www.selkirkcorp.com/literature/Brochure_-_ST_All_Fuel_Chimney_Installation_Guide_-_US.pdf

The single wall pipe is secured by your heater at the bottom, then attaches to the adapter that fit's at the bottom of your ceiling, and then it's double wall insulated from there up. The outside chimney must be supported if it's beyond a certain length. I didn't need to.

[nhdog]

i have done the same thing a few years ago using their super vent pipe model jsc. it is sold here in canada by most all the big box stores selling lumber and hardware. it is the perfect safe way to go,easy for anyone to put up by them self. i have had no problems and it will out far outlast me. here is the link to the canada info.

http://www.supervent.ca/-/media/selkirk/reference-documents/common/file/product-literature/chimney/supervent-jsc/catalogue-supervent-jsc-jsc001-e.pdf

[maple flats]

I ran single wall 12" pipe from my base stack and up thru the roof. Then at about 2' above the top of the base stack I had 1.5" 2300F rated ceramic insulation that was clamped to the pipe and it ran up until tight against the underside of the roof steel. At the bottom edge of the "clamp" I slitted and bent it in to keep the insulation from slipping downward. I had to get a fire dept inspection because I was allowing visitors in while boiling. They liked it. I made the clamp out of 28 ga galvanized sheet metal and folded 1" of it 90 degrees to form the clamp on one edge, on the other I folded it out, then doubled it back at 180 degrees, then at 1" another 90 so it slid under the first side. Then I drilled 1/4" holes and added 1/4" bolts to clamp it snug. When installed it was about 13.5" O.D..
That worked fine from 2007-2020 when I quit boiling. The 1.5" ceramic blanket kept the heat from the trusses, it got barely warm to the touch.
Above the roof, I covered the somewhat tight opening around the stack with a tight fitting oversized collar that kept about 99.99% of the moisture from running down the stack. With a extremely hard rain I occasionally got a slight dampness around the base stack. I suspect it was blown in under the collar.

[Pdiamond]

What you are saying is that you made a double wall pipe, is that correct Dave?

[Swingpure]

I ran single wall 12" pipe from my base stack and up thru the roof. Then at about 2' above the top of the base stack I had 1.5" 2300F rated ceramic insulation that was clamped to the pipe and it ran up until tight against the underside of the roof steel. At the bottom edge of the "clamp" I slitted and bent it in to keep the insulation from slipping downward. I had to get a fire dept inspection because I was allowing visitors in while boiling. They liked it. I made the clamp out of 28 ga galvanized sheet metal and folded 1" of it 90 degrees to form the clamp on one edge, on the other I folded it out, then doubled it back at 180 degrees, then at 1" another 90 so it slid under the first side. Then I drilled 1/4" holes and added 1/4" bolts to clamp it snug. When installed it was about 13.5" O.D..
That worked fine from 2007-2020 when I quit boiling. The 1.5" ceramic blanket kept the heat from the trusses, it got barely warm to the touch.
Above the roof, I covered the somewhat tight opening around the stack with a tight fitting oversized collar that kept about 99.99% of the moisture from running down the stack. With a extremely hard rain I occasionally got a slight dampness around the base stack. I suspect it was blown in under the collar.

I am trying to get a reasonably priced piece of 4 foot chimney pipe, but if not, your idea sound good. Could I use large stainless steel hose clamps to hold the ceramic blanket around the single pipe?

Thanks

[aamyotte]

I am trying to get a reasonably priced piece of 4 foot chimney pipe, but if not, your idea sound good. Could I use large stainless steel hose clamps to hold the ceramic blanket around the single pipe?

Thanks
That is what I am going to do for my chimney for next season. If I can't find clamps I will use wire and strips of metal to not compress the insulation where it is tied.

[Swingpure]

I ran single wall 12" pipe from my base stack and up thru the roof. Then at about 2' above the top of the base stack I had 1.5" 2300F rated ceramic insulation that was clamped to the pipe and it ran up until tight against the underside of the roof steel. At the bottom edge of the "clamp" I slitted and bent it in to keep the insulation from slipping downward. I had to get a fire dept inspection because I was allowing visitors in while boiling. They liked it. I made the clamp out of 28 ga galvanized sheet metal and folded 1" of it 90 degrees to form the clamp on one edge, on the other I folded it out, then doubled it back at 180 degrees, then at 1" another 90 so it slid under the first side. Then I drilled 1/4" holes and added 1/4" bolts to clamp it snug. When installed it was about 13.5" O.D..
That worked fine from 2007-2020 when I quit boiling. The 1.5" ceramic blanket kept the heat from the trusses, it got barely warm to the touch.
Above the roof, I covered the somewhat tight opening around the stack with a tight fitting oversized collar that kept about 99.99% of the moisture from running down the stack. With a extremely hard rain I occasionally got a slight dampness around the base stack. I suspect it was blown in under the collar.

If my stack was 8” single wall pipe and I wrapped it in the 1.5” ceramic blanket in the critical area and for that critical area have the 8” pipe and ceramic blanket inside a 10” diameter single wall pipe, would that work?

Maybe I would make tabs at the bottom of the ten inch pipe and bend them in, just to close off the bottom, and I could add a storm collar for an 8” pipe at the top to help prevent any water getting in.

[MajorWoodchuck]

I was thinking about just going through the roof with a single wall pipe as well because I am trying to build my shack for as cheaply as possible. About the only materials I bought new were the concrete for the base and the steel for the roof. After looking at it more I sprung for two 36" sections of 8" insulated Supervent where it goes through the roof and next to the coupla. Below that I plan on using 8" single wall galvanized pipe inside of 12" duct to go to below my truss bottoms . I may even try to roll a sheet of excess 36" roof steel to put in between the 8" & 12" with the ribs keeping the space more even and adding another layer of heat shielding.
It just doesn't pay to jepodize all my work to save $200 where it goes through the roof and then it is all SS on the outside exposed to the elements.

[Swingpure]

I picked up a 2’ piece of double wall pipe, that my 8 “ single wall pipe can fit into. I think that should work for me. I wish I had my base stack now so I could set it all up, but will likely have to do it all in January or February.

[Swingpure]

I just chatted with the gentleman who will be building my pan and base stack and he has a 36” long double wall pipe that I will buy. The base stack and pipe with it are 8’ tall. I will put the double wall pipe on that, then add a couple of feet to the other end with a storm collar on it.

[Pdiamond]

Why are you concerned about having stainless steel exposed to the elements? My chimney has been up going on six years now and I have had zero issues with the double wall. Just asking.

[MajorWoodchuck]

Sorry I was not clear. Having SS on the outside is better than galvanized or black stovepipe. It should stay shiny for years.
Glad you are going with some better chimney pipe Swingpure.
For my stack to roof connection I got a side table from a commercial sink for $5 that I can cut a 20" x 40" sheet of stainless from. I plan on bending it in the middle to match my roof pitch and cutting a hole that tightly fits my insulated double wall pipe. A clamp around the pipe will keep it from sliding down and a bead of silicone should seal it up. Then just stick it on top of the roof steel at the peak.

[Swingpure]

Sorry I was not clear. Having SS on the outside is better than galvanized or black stovepipe. It should stay shiny for years.
Glad you are going with some better chimney pipe Swingpure.
For my stack to roof connection I got a side table from a commercial sink for $5 that I can cut a 20" x 40" sheet of stainless from. I plan on bending it in the middle to match my roof pitch and cutting a hole that tightly fits my insulated double wall pipe. A clamp around the pipe will keep it from sliding down and a bead of silicone should seal it up. Then just stick it on top of the roof steel at the peak.

So the bend in the stainless steel plate fits over either side of the peak of your roof, with a hole on one side for your pipe?

[MajorWoodchuck]

My pipe is going through the peak in the roof. Will need to cut half out on both sides of the bend. I have homemade trusses and 15mm OSB on roof so no ridge board to worry about. 3.75" wide trusses are 27" on center so chimney is centered between them. CAD print will help to layout the hole the chimney pipe makes coming through the peak sheet.

[maple flats]

What you are saying is that you made a double wall pipe, is that correct Dave?
I did make a double wall pipe, but all double wall pipe I've ever seen is 1" of insulation between the inner and outer layers, I had 2 layers, each 1", but they were compressed into 1.5". While compressing insulation is normally not recommended, it did perfectly that way for 13 seasons, until I retired.

[Vtmbz]

I have to step in here. Retired chimney mason, seen everything, including lots of charred rafters and roofs.

Insulating wood members is considered a bad idea as it retains heat right where you dont want it. Evaporators are essentially chimney fires, its a very extreme application of fire. Many people will tell you about flames shooting up a stack eight feet above their arch, including me. As noted, it gets very very hot up there.

I set my arch up by building a square chase two feet square through my ceiling clear to the steel roof. That way i could visually inspext the whole run of pipe at all times. I cut all the roof strapping out of the two foot hole so there is nothing flamable in that section, and i can see the steel from the floor. It is enclosed so the attic space is separated. Dont fabricate a home brew pipe in this section, its just not worth the risk

In my area used Selkirk metal bestos in the size you need is common. No need to buy new. Usually half the cost at least.
One tip: keep the area where the sections join away from wood because there can be some settling of the insulating material in used pipe if it isnt pristine and carefully handled. The newer pipe probably doesnt have this problem like the old stuff did.

I did a refractory wrap with wire in one part for a while, but didnt like the idea of squirrels maybe tearing it up. I kept looking at it during a boil, and finally replaced it.

Make certain that in no case can the pipe ever come loose. I used heavy steel strapping (not pipe hanger strap) lag screws and nuts and bolts. Remember that while you are putting out chimney fire, your pan is melting.

Used mb will generally come with a roof kit designed for the purpose. I bought roof kit for a ten inch pipe and ran a7” insulated pipe through that, so there is air exchange between both as well. Lots of air space above the roof, then there is a collar that comes with the roof kit that can be siliconed when done. In my case, i dont object to a little rain because it runs clear down the stack. Above the roof, single wall pipe is fine. I use stainless pipe here. Galvanized pipe wont last long in this application. For the record, the chrome burns off the first year so shiny is out, but it doesnt rust and stays solid. I guy that in place with electric fence wire, lots of excess so i can take the stack down when wanted and reuse the wire.

Sugar houses burn down all the time around here. It sucks, so dont reinvent the wheel.

[Swingpure]

Thanks.

In my case I do not have a ceiling and my trusses in that area are five feet apart. It is open air up to the metal roof and open air above the metal roof.

I will have a brand new 36” long double wall pipe going through the metal roof. The double wall section of pipe should weigh around 35 lbs.

The one thing I have not finalized yet is how to support the double walled pipe. I was debating running two, five foot plus long, 1/4 to 3/8” flat iron on top of the cross chords of the trusses and let the double wall pipe sit on them. I was also thinking of having a piece of ceramic blanket sandwiched between the flat iron and the truss.