Going Through the Back Wall vs. Through the Roof

[bigschuss]

Hello everybody...I am really hoping to be able to use my Mason 2x4 evaporator this spring in my new sugar shack. Everything is all set except for my pipe.

Quickly...I was thinking about sending the pipe out the back wall and then up the outside of the building. I seem to recall though reading somewhere at some point that there is a drawback to having the pipe on the outside of the building vs. inside and going up through the roof. Can anybody help me with this? Is there an advantage to having the pipe go through the roof?

Thanks in advance.

6536

[spencer11]

You get a better draft through the roof cause the pipe is straighter

[heus]

Straight up is preferable but if you do use an elbow I would make the stack about 1/3 taller than normal.

[hammer460]

Bite the bullet and cut a new hole in that new roof. When I was boiling in my wood shed, I put the stack out the back and got a terrible draw. Dry softwood wouldn't burn. Any horizontal pipe doesn't work.

[SevenCreeksSap]

Easy to say bite the bullet when you didnt shell out the bucks and time putting on that new metal roof. I couldnt cut a hole in mine either, so went through the back wall as close to the roof as I could, used a 45 on each side of the wall so the pipe going through is at the 45 deg. angle. I did use metal around the pipe so its not near the wood and check it to be sure the heat isn'tgetting to the wood. no problems so far. with 8 in pipe I dont have any draft problems.
I'm sure may not be as good as the straight pipe, but I dont have a hole on my new roof either. Maybe someday I'll change it, but I figure I'm only going to get so much draft and boil rate anyway. to me the differenc in the boil rate probably wouldnt be worth it.

[TerryEspo]

Thru the roof is prefered in all woodstove installs. Not saying that back wall doesn,t work, just straight up is better than anything else. My garage woodstove is out the side wall and no issues in 15 yrs., but straight up IS better. The pipe stays warmer, better draw, less creosote due to less angles.

I like what Seven Creek did with his pipe, the new metal roof , I would do the same.

Looking at your open ceiling design, I feel you could go out the back wall, just gett,er up high before going outside with it. Not too high though, watch your clearances.
Both ways will pass building codes, so either way you go will be fine.

Love the Shack !!

Terry

[cadocter]

I ran mine up about 9 foot inside the shack and then poked straight out through the wall. From here I put another 90 on and ran it straight up another 5 or 6 feet. I get great draft with my half pint. Maybe if I had a bigger Evaporator I'd have some problems but this works great for me. I used a piece of triple wall laid on its side to go through the wall.

[Dave Y]

A straight flue will draw better. this is important if you are natural draft. roof jacks are made for holes in the NEW metal roof. I have three stacks going thru my roof with no issues.

[heus]

Heres the thing. If the building is going to be a sugarhouse, go through the ceiling. If its only temporary then go through the wall. I know its hard to cut through your new roof but trust me you will be happy you did.

[bigschuss]

Thanks everybody. I appreciate the responses.

One more question...what is the purpose of the tapered base stacks I see listed on Bascom Maple's web site? I am a complete beginner at this.

[spencer11]

its so the draw is over the entire width of the pans, and not just in the center 6 or 8 inches or whatever size your stack is

[SevenCreeksSap]

Well you started right. That is one nice building for a 24 tap operation. Most seem to start in the driveway.

[bigschuss]

Well you started right. That is one nice building for a 24 tap operation. Most seem to start in the driveway.

I should clarify a bit. I have been outside on a backyard rig for about 8 years...see pic attached. I bought a Mason 2x4 last year and finished my shack and am ready to move in and take it to the next level. But I am a complete beginner when it comes to the evaporator, the shack, etc. As I grow I could see myself expanding. I'm on 150 acres and could probably do 200 taps if I ever desired. Who knows? Maybe someday.

For the time being I'm just trying to figure out what Spencer 11 just explained about the tapered base stacks? LOL.

Thanks again...

http://i143.photobucket.com/albums/r143/bigschuss/P3200002.jpg

[bigschuss]

Thanks Spencer. I'm still a bit confused. Does this mean that the back of my evaporator needs to be specially cut to receive that base stack? My Mason 2x4 has a small circular 6" hole.

[Fishgill]

With this evap you need to use a regular 6" stove pipe. I have the same rig.

[spencer11]

with the half pint, and the small mason evaporators they dont have a base stack i believe, just cause of there size. but like mine(2.5x8) or any of the bigger wood fired rigs thats when you would need a base stack

[bigschuss]

O.K....think I got this. Base stack not necessary...and now just have to decide to go through the roof, or out the back wall.

Thanks everybody.

[DonMcJr]

My Half Pint goes 6 feet up then out the back wall with 2 90's and then up about 10 more feet. Works Fine for me!

[bigschuss]

My Half Pint goes 6 feet up then out the back wall with 2 90's and then up about 10 more feet. Works Fine for me!

Thanks Don. Good info!

I recognize your user name from the QDMA forum.

[DonMcJr]

You're welcome! It's a small internet world huh? LOL

[PeddlerLakeSapper]

With forced air, draft is not a concern.

[Pete S]

The tapered base stacks allow a better chance for an even draw across the whole width of the evap.

As for a response to your origional question. I just recently finished my metal roof on my sugar shack/barn. I can not bring myself to cut through the roof for the stack.

I will be getting an 8" stainless flue pipe that is being built to go out the wall/gable, then vertical to the point of termination. My horizontal portion is about 6' and my vertical is 12'.

Would it work better to simply go straight up from the evaporator, possibly. Temperature differential creates a draft, as well the taller the chimney, the better the draft usually.

I "PLAN ON" using 2-8" chimney blocks for a thimble through the wall to protect the wood from the pipe.

IF it doesn't draft as well as I'd like, I can always cut a hole in the roof. (my 14/12 piched - rough sawn planked- hand framed- $900.00 metal sheeted,............. *sniffle*)

[GramaCindy]

I am just in my third year, second in the new shack…but the set up has been the same for the last two years. No problems, we sent the stack straight out the back with an elbow sending it up on the outside. Would we have had a better draw by having the stack inside for several feet, and then putting in the elbow to head out? I can't figure out how it would make a difference. Educate me please…. I have had what I consider really good draft and use a small blower for AUF. I would say that I boil 10-14 GPH, (rough guess) on my Mason insulated Firebricked 2x4.

[DougM]

Your stack should be at least twice the length of your evaporator, so that should be your starting point. But - according to my friend who is an HVAC guy - each 90-degree elbow subtracts 6' from your length. We didn't realize there was that much loss when we installed the stack on our 2.5x8, which has two 90-degree bends. Up until last year we had about 22' of stack, so effectively we only had about 10'. We re-calculated for the 12' loss in the bends, and added enough that our effective length is now over 16'. Last year we were doing well to get 35gph, now we're consistently at 50+.

We had the same issue with going through the roof, but are now considering changing it. The horizontal run is not great, and we would probably get more GPH with a straight pipe, but if you add enough stack to compensate for bends you can still get decent efficiency even with the bends

[bigschuss]

Thanks for the great responses everybody. Much appreciated.

[bigschuss]

Bringing this one BTT with some updated pics as per request....

I ended up going out the back wall. I've used it two seasons now with no issues. Now I just need to figure out a pre-heater. The one that came with my Mason 2x4 is not very effective.

http://i143.photobucket.com/albums/r143/bigschuss/Sugar%20Shack/IMG_0505_zpsqrvgztgk.jpg
http://i143.photobucket.com/albums/r143/bigschuss/Sugar%20Shack/IMG_2409_zpsrvzpyu1x.jpg
http://i143.photobucket.com/albums/r143/bigschuss/Sugar%20Shack/IMG_2408_zpscxjsn7n3.jpg
http://i143.photobucket.com/albums/r143/bigschuss/Sugar%20Shack/IMG_2407_zpsdmqfygmo.jpg

[bigschuss]

Outside....

http://i143.photobucket.com/albums/r143/bigschuss/Sugar%20Shack/IMG_0502_zps6wthpssi.jpg
http://i143.photobucket.com/albums/r143/bigschuss/Sugar%20Shack/IMG_2410_zpsjbknpdvj.jpg

[adk1]

Nice setup.