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Small Cabin Forum / Off-Grid Living / The process has started (stove installation advise)
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neb
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# Posted: 14 Dec 2013 16:02 - Edited by: neb
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I went up to the cabin today to take a look on how to install the stove. I would like to go through the wall with flex pipe and not so sure about the roof exit. I will have plenty of room for clearances but still not sure. Help me make a decision on what to do. I set it in there in the corner and side ways so is there any advise on that?




rockies
Member
# Posted: 14 Dec 2013 17:12
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Well, you don't have any view of the fire so there's no point in aiming it out into the room at a diagonal. You'll have to install a fireproof material behind it on the walls (probably up to 6 feet I would guess although your local government might have specific codes for that) and you'll have to have a fireproof hearth sticking out about 2-3 feet on the front and side. Again, check with the local government. Your stove is pretty small so bear in mind that going through the wall causes the stove to have less of a "draw" for the air up the chimney since it has to get around the bends in the pipe. You'll have better airflow if you go through the roof.

neb
Member
# Posted: 14 Dec 2013 17:24 - Edited by: neb
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rockies
Yep I will get the protection on the walls and floor that won't be a problem. As for viewing the fire not a big deal for me but I do think I will face it diagonal this will give more clearance from walls. I do know the cons in going through the wall but I really don't want roof to leak and would be less of a problem going out the wall. The chimnay is exhaust pipe and I have some flex exhaust pipe that would work very well if going through the wall. On this stove I have a venting system on the back of the stove which helps the draft up the pipe. That is what it"s for and works well if open till fire gets going and then you can shut it. I would like to go up there tomorrow and get started but I'm not sure roof or wall????? I forgot about the post that was started through roof or wall. I wish I would of added this post to that sorry I messed up.

redlandfd
Member
# Posted: 14 Dec 2013 21:20
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I like it, I also plan to use a side "chimney" for my stove. Same reason, don't want to cut into the roof.

neb
Member
# Posted: 14 Dec 2013 21:48
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OK that is what I will do I will go through the wall. If for some reason it doesn't work then I may have to go through the roof. I want to get the hole cut and plywood removed tomorrow and start to install fire wall. Thanks for your help.

toyota_mdt_tech
Member
# Posted: 15 Dec 2013 20:31
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Go through the roof. Wall exist are flat homely. Uuugggggggggggggglllllllllyyyyyyyy.

Get a redi made hearth for the corner, then install your backboard. Use a good support box, then the double wall stainless pipe from that point up.

neb
Member
# Posted: 15 Dec 2013 21:11 - Edited by: neb
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I went to the cabin today and still not sure what I want to do with the pipe. I'm leaning going through the roof could you guys give me some pointers. The roof is ribbed not flush tin so that is some of the problem I can get a hole cut dead center bewteen the rafter that are 24 center. Dead center is right on top of the 2 inch rib. My pipe is muffler pipe and is only 2 3/4 inch so I would have plenty of clearnace. My question if I make a tin box or frame one for the inside to protect the rafters would this work. I would cut out all the plywood bewteen the rafters so there would be just tin roof. I would have to install a roof jack to support the pipe and that will be the trick part with a ribbed tin. On the roof I would have to cut that hole right on top of the highest rib what would you do? Here are some pictures of inside roof above the stove.





davey25
Member
# Posted: 15 Dec 2013 21:12
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Ya and It looks bad if you don't put it diagonal

MtnDon
Member
# Posted: 15 Dec 2013 21:56
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If appears you are going to use single wall, non-insulated pipe through the roof or wall. If that is correct there is potential serious danger. It also appears that the metal panels are in direct contact with the wood studs at several points. That is also not a safe practice. Do you want to follow up on those concerns or do you not want to pursue that?

neb
Member
# Posted: 15 Dec 2013 22:12
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The tin fire wall is separated about 1 1/2 inch from the studs. It will have a good air flow from the sides by the window and from the floor. As far as the floor I haven't got that part done but yes I will install a FR product that is raised from the floor. As for the roof exit my question is could I cut out the plywood from rafter to rafter and install a fire wall (box) to protect the wood and rafters. I all so will shield the 2 3/4 in pipe going up to the roof with a shield. The pipe itself will be about 18 inches from the side walls on both sides. You can address my concerns.

bldginsp
Member
# Posted: 15 Dec 2013 22:15
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Wall protection is not necessary if you space the stove at the manufacturers stated clearances, but in your photos it looks like you are way closer than that. But wall protection for reducing clearances won't help unless its correctly designed. Metal on wood is not helpful, it needs to be spaced away.

Standard hearth projection from the front of stove is 16", 8 inches to the side.

I agree with MtDon- single wall pipe thru roof or wall is very scary. Heat builds in the enclosed cavity, so even with large clearances you can start a fire in the wall or roof. Might be worth doing a bit more research before you commit the instal.

bldginsp
Member
# Posted: 15 Dec 2013 22:26
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"Could I cut out the plywood from rafter to rafter and instal a fire wall box to protect the rafters".

I guess the problem here is knowing that your 'fire wall box' is really going to protect the rafters. The drop boxes used in many chimney installations are not fire protective, they just hold in place the fire protective device, which is the double or triple wall insulated chimney pipe section.

I think you are re-inventing the wheel. Chimney components are expensive but that's because it's hard to make a truly fire protective device, given how hot wood fire chimneys get. I strongly suggest you go with standard chimney parts like the Simpson dura vent equipment, and follow your stove makers instructions.

neb
Member
# Posted: 15 Dec 2013 22:42
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If you read my post I'm 18 onches from the side walls and 10 inches from the corner. So that is why I installed a fire wall. There is no tin touching the studs the tin is 1 1/2 inch from the suds. I also will install a hearth and I will be more then 16" in front and more then 8" on the sides and back of stove. The stove will never be used unless there is snow on the ground and we usaully get about 3 feet on the level If this was in a city yes I would have a pro install but not going there with this project. This stove will never be used unattended and will be used as a day thing or an afternoon place to wam up. I will also sheild the pipe going up. My question is if I cut out the plywood 24" x 24" and install a tin box with air space between the rafters and have the pipe go through the tin and out to the sky would you do this. We are talking outside temps of minus degree days so tin roof would be as cold as you know what.

MtnDon
Member
# Posted: 16 Dec 2013 00:01
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From the pictures I could not tell precisely how the sheet metal wall shield was installed; that is why I brought it up. If you have a minimum 1.5" air space from studs to the sheet metal, and if there are no fasteners in the area immediately behind and beside the stove that is good.

Quoting: neb
would you do this.


I can't definitively say yes or no. A lot depends on things I can not see, like how the "tin box with air space between the rafters" is installed, the dimensions, etc. My personal opinion is that going outside of the prescribed methods for safe chimney and stove installations is literally playing with fire.

I recognize that you would have a near impossible time locating insulated chimney pipe for the flue on that stove. That makes this a harder job than for other stoves that are designed for use in a building. I do know that if a person is not careful with one of those they can get extremely hot. At times, as in -20 degree weather and a canvas hunt tent that can be welcome, but I've also seen a tent fire because of stoves like that. Not to mention a case of bad CO poisoning.

As for the hole in the roof material I would use a hole saw and drill/saw the hole where it was needed. A drill with sturdy side handles is needed as those sometimes hog in suddenly. Second choice for me would be a 32 tpi metal cutting blade in a jig saw.

If you install that with the single wall pipe poking through roof or wall be aware that the chimney that is outside will cool very rapidly in very cold winter temperatures. That can lead to a surprisingly rapid build up of creosote. Insulated chimneys do more than protect the combustible materials from excessive heat. They also help keep the chimney warm. Warmth helps slow down creosote deposition as well as help to maintain draft.

neb
Member
# Posted: 16 Dec 2013 08:30
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MtnDon

Thanks for the advise and you hit it on the head not easy finding such an animal for that size of pipe. I have been around wood stoves most of my life but never have owned one or installed one. Wall tents I have spent weeks at a time in them with a stove like this one and had no problem but yes safety is number one. There is nothing saying one can't use single wall pipe up through a roof. What I can do is get a 4 inch stove and maybe run this 2 3/4 in through it and still drop box and do that thing. I also will shield the pipe leaving the stove.

Dillio187
Member
# Posted: 16 Dec 2013 15:00 - Edited by: Dillio187
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I'd be tempted to run the smaller pipe up near the ceiling, then install a cathedral box and 6" class A (the shiny stuff) through the roof with a real thimble. Then, in the future if you ever want a larger stove, you already have the hard part done, and can just install your new stove. This would also be safer than trying to home brew your own setup. I absolutely would not run a single wall pipe through the ceiling or wall, even with it stuffed inside another pipe.

http://www.northerntool.com/shop/tools/product_200316635_200316635?cm_mmc=Google-pla- _-Heaters%2C%20Stoves%20%2B%20Fireplaces-_-Heater%2C%20Stove%20%2B%20Fireplace%20Acce ssories-_-36625&ci_src=17588969&ci_sku=36625&gclid=CM3D3Y_EtbsCFVBgMgodrgkAHg

toyota_mdt_tech
Member
# Posted: 16 Dec 2013 15:06
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As Mt Don said, from the support box upward is usually the larger insulated pipe. Why can you just run 6" pipe from support box out, then stick your smaller pipe inside of it, flashing the area where the smaller pipe enters the support box. Nice thing would be , is later, you can just install a woodstove if you ever wanted to without changing much. Then you can get the roof jack, they are a thick softer metal, you form it to the ribs with a rubber mallet to your metal roof. So it would look like a std stove pipe, be safe, and still work with your smalelr exhaust pipe???? And if you ever wanted to go woodstove or a propane unit with a 6" pipe, you are ready to roll.

toyota_mdt_tech
Member
# Posted: 16 Dec 2013 15:07
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Just seen Dillios response, same idea I had.

Dillio187
Member
# Posted: 16 Dec 2013 15:55
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beat you to the punch by 6 minutes. I probably type faster :D

I forgot to add, the adapter from 3" to 6" is also readily available.

http://www.homedepot.com/p/DuraVent-3-in-to-6-in-Double-Wall-Pellet-Vent-Chimney-Pipe -Adapter-3074/100679686

MtnDon
Member
# Posted: 16 Dec 2013 16:31
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There is one potential issue with adapting from the small pipe to a larger diameter pipe. That is the speed of the airflow up the pipe.

The 2.75" dia. pipe has a cross section area of a little over 5 sq inches. The 6" dia. pipe has a cross section area of a little over 28.25 sq inches, or about 5.6 times the area. That means when the smoke changes from the small pipe to the larger pipe is slows down a lot. That can have 2 results. One, the draft strength is reduced. Two, when the smoke slows it also loses heat. That could promote creosote formation. It can not be predicted how the change of pipe size will affect the performance of that stove.

In the case of modern EPA approved stoves a change from a 6 inch to an 8 inch chimney can have adverse effects. For example one of our wood stoves can be used with the doors open or closed. The stove is rated for 6 or 8 inch pipe, but if used with an 8 inch chimney the manufacturer recommends to not use the stove with the doors open. With a stove like the one you have Neb, that might not be a problem as it does not have the convoluted smoke path that many EPA approved "clean burn" stoves have.

If you did install a six inch through the ceiling/roof pipe assembly and if it did not draft well, you could always run the skinny pipe up through the inch pipe.

bldginsp
Member
# Posted: 16 Dec 2013 16:36
Reply 


Single wall pipe through any enclosed wall or ceiling cavity is a really bad idea. Heat is trapped and has no where to go.

neb
Member
# Posted: 16 Dec 2013 19:29
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Dillio187
toyota_mdt_tech
MtnDon
bldginsp
You guys got it all figured out and I really do appreciate all your time and expert advise. I will run the bigger pipe up through then use the pipe I have to run up the center and from support box. I will get the roof jack and make it work with the ribbed style tin I have.
MtnDon again thanks for the detailed info you share.
I will let you know if I burn the joint down. LOL No really safety to me is number one and it will be safe I can tell you that.

bldginsp
Member
# Posted: 16 Dec 2013 20:51
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I wonder what the manufacturers would say if they knew that you were running an auto exhaust pipe up through one of their chimney sections as an insulating/fireproofing method. But it seems like the best precaution in your particular circumstances. I talk to fire fighter professionals on a regular basis and they wince when the subject of woodstoves comes up, even when they are installed with the seemingly overprotective stuff we prescribe for woodstoves. Wood structures and 'contained' fires are a bad but necessary mixture. I don't think you are going to burn your place down because you are thinking about it, which is a lot more than I can say for some job sites I visit. Keep us updated.

bldginsp
Member
# Posted: 16 Dec 2013 20:58
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The other thing I wanted to say is that just because the tin on the wall is spaced away doesn't mean it is necessarily safe. Doing that allows you to reduce the clearances that the stove is made for, and only by a certain amount. If you exceed that amount, and are too close to the spaced tin, the tin itself can get hot enough to cause the wood behind to ignite. This is particularly true with an unsheilded stove such as yours, which will produce a high degree of radiant heat. I suggest you find out what the stove clearance is, find out how much the spaced tin allows you to reduce that clearance, do the math and space the stove accordingly.

I know I sound like an old ninny and I'm sorry, but in my trade we look at the statistics of the dead three year olds.

toyota_mdt_tech
Member
# Posted: 16 Dec 2013 22:48 - Edited by: toyota_mdt_tech
Reply 


Neb, to keep the velocity or air flow up to snuf, (what Don mentioned) run your smaller pipe right through the reducer (6" to 3") and run the smaller pipe right up to just under the chimney cap, but inside the bigger pipe. You may have to rig up some sort of stand off (metal strapping) right at the top to keep the pipe centered up inside the larger pipe. The reducer at the bottom would be good enough to center it at the bottom. This way you have the larger pipe set up, easy to get all your hardware, plenty safe as its inside the shiny double walled insulated pipe.

I might add, you can have a metal shield made, maybe some 1/8" plate steel bent at 90' total, but with 2 of the 45' bends to shield your stove from the heat. It can set behind your woodstove. But to be in compliance, it just needs to be permanently secured to the stove, so it cant be removed or fall over etc.

neb
Member
# Posted: 16 Dec 2013 23:31
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toyota_mdt_tech
Thanks again and that will be what I will do. As far as the shield around the stove I will also do that. I did read also that it has to be secured to the stove so I will get that done also. Thanks for the help.

toyota_mdt_tech
Member
# Posted: 17 Dec 2013 00:22
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The shield will greatly reduce your clearances too. So if you are crowded for room, this will square you up. Good luck, sounds like you have a good plan, post pixs for us to see as you progress.

neb
Member
# Posted: 17 Dec 2013 19:21
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Yep I will work on it when weather is good to do so and keep you posted.

MPL
Member
# Posted: 17 Dec 2013 19:58
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You can use "concrete" board as shield 1/2" if you can find it. The flue can be straight up (through roof) with a roof shield + storm collar + rain cap. (Probably 6" flue material subject to stove model). If you need assistance on selecting a stove let me know (I represent over 60 different manufacturers). Interior flue can be single wall then use
cylindrical flue connection (e.g. firestop) to connect to double wall as
you exit the roof and continue up through roof. Your draft will improve
if you have at least 10' foot of flue length.

neb
Member
# Posted: 17 Dec 2013 21:44
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I have another question about the double wall pipe. I went and got a 3 1/2 " x 36" double wall stove pipe. It is listed for use on oil and pellet and the guy told me it will work for wood also. Can some tell me if this pipe will be ok for wood. My stobe pipe I got with the stove will fit inside this double wall and have about 3/16" gap around the side of the double wall pipe. Please tell this will work! LOL

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