Sugar house loft joists size

[calvertbrothers]

Does anyone have sap tanks in a loft? I’m building a new sugar house it will be 24x36.
I need a 500 gallon concentrate tank, probably store line and empty barrels in the loft. What centers on the joists and what size lumber for the joists?

[n8hutch]

I used 4x8 rough sawn Hemlock 2' on center. My sugarhouse is only 20' wide. Wish it was 24 . Lol good luck with your design/build. If you use dimensional lumber i would just go 2x8/0r 2x10 , 1 foot on center.

[Kh7722]

We built ours in 2019 and is a timber frame. We have a 300 gallon head tank and designed it to have two of them, one on each side of the loft. The joists are 8x8 three feet on center and clear span a 16’ opening. The 8x8s rest on a 8x14. The timberframer said tanks would not be an issue upstairs

[darkmachine]

I have a set of plans with a timber frame loft, they call for 4x8 on 2ft center. I'd like to see pictures of people's head tanks in their lofts. I have a 200 gal zero tank to use, but I have room to go bigger. My shack will only be 14x16 though, might be snug, but wood storage, and equipment will be separate

[TapTapTap]

500 gallons is about 4500 pounds which is a lot of weight to have over your head. I got my concentrate tank in the loft over the kitchen-RO room at the end of our 16x34 sugarhouse. We used the UVM sugarhouse design and added 10 ft to the end for the heated kitchen room with the cold loft above. The loft joists span the 10 dimension for greater weight capacity supported by an internal bearing wall and the gable end. I was still concerned about the weight so I installed three pairs of heavy back-to-back steel angle sections for carrying the load. The angles are used 5x3x3/8 from a railroad bridge rehab project.

[TapTapTap]

22336

Photo of my framing during construction.
Ken

[GeneralStark]

As Ken said that is a lot of weight to have in a loft so proper design is key. I have a 250 gal. head tank supported by 4x8 rough hemlock but the span is only 7 ft. as I incorporated the framing of the heated room in my building to support the 4x8 joists. Spanning 24' without any posts or load bearing walls would require some very significant framing.

So, perhaps you could consider the overall design of the building and whether or not you really need a completely open floor plan or if you could incorporate some other support to reduce the overall span distance.

Another thing to consider is it can get pretty warm in a loft so it may be worth considering exactly how you plan to use the 500 gal. tank.

[n8hutch]

My span is only 10 feet to the center, I have an approximate 1000 gallon tank up there , even at 8000lbs, that is only 55lbs per square foot with a 12x4 tank... there are plenty of calculators online that will help you determine what you need.

https://www.awc.org/codes-standards/calculators-software/spancalc

[jrgagne99]

Does anyone have sap tanks in a loft? I’m building a new sugar house it will be 24x36.
I need a 500 gallon concentrate tank, probably store line and empty barrels in the loft. What centers on the joists and what size lumber for the joists?

Not enough information. You need to specify the span and where the weight will be (middle vs. edges vs. all over.) Suggest an online calculator, they abound.

[DrTimPerkins]

Photo of my framing during construction.

Like Ken, we have a couple of steel I-beams running under the rafters to avoid the need for posts, to support a few point loads (refrigerated bulk tank). and for a trolley system to lift and move the evaporator and accessories.

[TapTapTap]

My span is only 10 feet to the center, I have an approximate 1000 gallon tank up there , even at 8000lbs, that is only 55lbs per square foot with a 12x4 tank... there are plenty of calculators online that will help you determine what you need.

https://www.awc.org/codes-standards/calculators-software/spancalc


N8: I don't agree with your analysis. If you divided the 8,000 lb load for the entire area of your loft then you would need some way of transferring that load evenly to every joist and uniformly on every joist to make that assumption valid.

For that kind a weight, I would be running at least a 2x10 joists at 16" spacing. But with that kind of weight, I'd be adding extra redundancy beyond the joist calculation and beyond the joists to the entire building framing.

[DrTimPerkins]

The real purpose of a standard ceiling joist is to hold up the ceiling, not to support an additional load placed on top of them. Many a building has been damaged by trying to support a load from them. If you want to support a load, you need to make sure the structure is in place to support it properly. Otherwise the best you can hope for is that the joists and roof will be sagging after some time....the other possibility is collapse. Make the correct assumptions based upon data, do the analysis, and build it properly.

[calvertbrothers]

Not enough information. You need to specify the span and where the weight will be (middle vs. edges vs. all over.) Suggest an online calculator, they abound.

I was thinking of running 10x10’s down the center of the sugar house for support columns. Leaving 12ft on each side. The weight would be in the center. Support columns I was thinking every 12 feet.

[TapTapTap]

Make the correct assumptions based upon data, do the analysis, and build it properly.

I agree. And just to be clear, my back-to-back steel L5x3x3/8 framing is not a typical beam configuration. I would recommend steel beam sections over L sections mainly because the design is more straight forward.

[TapTapTap]

I was thinking of running 10x10’s down the center of the sugar house for support columns. Leaving 12ft on each side. The weight would be in the center. Support columns I was thinking every 12 feet.


I think you should be consulting with a structural engineer. I don't think a traditional carpenter should design this without professional help.

Also it sounds like the arch will be offset from the centerline of the sugarhouse. Are you thinking of a hood or open with a cupola? For the open option, the cupola should be directly over the rig.

[n8hutch]

2233722338

Your coupala can be off center this is how I did mine, while it doesn't have an engineers stamp it has been up 5 years and I am pretty sure it will stand for 100 more easy. If you are not comfortable designing your building for a loads get a friend to give you a hand that has done that kind of thing quite a bit. I personally tend to over engineer things and anyone who has actually been in my sugarhouse can see that. Good luck to you with your build/design. There's always more than 1 way to skin a Cat.

[TapTapTap]

2233722338

Your coupala can be off center this is how I did mine, while it doesn't have an engineers stamp it has been up 5 years and I am pretty sure it will stand for 100 more easy. If you are not comfortable designing your building for a loads get a friend to give you a hand that has done that kind of thing quite a bit. I personally tend to over engineer things and anyone who has actually been in my sugarhouse can see that. Good luck to you with your build/design. There's always more than 1 way to skin a Cat.

Nate,
I realize that I was not that clear but I did not suggest that a cupola needed to be in the center for structural reasons. I was less clear that you would want a hood if your rig wasn't directly below your cupola due to the reduced effectiveness. It appears that you have a hood and steam stack. Without a hood, steam management can be a challenge even in ideal configurations. From your photos I can also see that the roof rafters run through the cupola, which I agree with regardless of the cupola location. As for over-engineering, I agree with that thinking and I apply it constantly. From a structural perspective, I look for extra member capacity, good alignment, solid load paths to the foundation, adequate bracing for global and member stability, and redundancy in the connections. For the average person - be very wary of specialized construction (like sugarhouses) and seek professional help when working beyond your ability.
Ken

[bill m]

My span is only 10 feet to the center, I have an approximate 1000 gallon tank up there , even at 8000lbs, that is only 55lbs per square foot with a 12x4 tank... there are plenty of calculators online that will help you determine what you need.

https://www.awc.org/codes-standards/calculators-software/spancalcHow did you calculate these numbers? The weight of sap at 2% is 8.34 lbs. per gallon so 1000 gallons would be 8340 lbs. A 12x4 tank is 48 square feet which calculates out to 173.75 lbs. per square foot.

[bigschuss]

2233722338

I personally tend to over engineer things and anyone who has actually been in my sugarhouse can see that. Good luck to you with your build/design. There's always more than 1 way to skin a Cat.

Nice interior. If I had built that I would have used a double header to receive those rafters...and joist hangers for the header, and joist hangers on the rafters where they tie into the header. That would have been over-engineered! :D

[bigschuss]

How did you calculate these numbers? The weight of sap at 2% is 8.34 lbs. per gallon so 1000 gallons would be 8340 lbs. A 12x4 tank is 48 square feet which calculates out to 173.75 lbs. per square foot.

I was wondering about those numbers myself. An 8340 lb. tank sitting on 5, 6, or 6 rafters is going to exert a serious load. 10x10 columns mid span and the weight directly over those columns will help. But, 8340 lbs. is a little over the weight of 2 Chevy K5 Blazers sitting over your head....I think some serious thought needs to go into the design of the loft.

[n8hutch]

You are absolutely right I did have a mathematical error there. My tank in reality is closer to 800 gallons I was just rough estimating, it sits centered on a main carrying beam so the load is spread out over the whole up stairs and easily falls under the 100 lbs per square ft that I used to figure out my beam size, a 4x8 rough sawn timber spaced 24" is roughly equal to a dimensional 2x8 spaced every 10". It is supported by 10 floor joists that sit on 4x8 sills that are supported by 6x6 verticle posts that fit together. Everyone has a different way of doing things , and i have certain seen and participated in plenty of"i would have done it this ways" in my life. thats what makes visiting other sugarhouses neat. Not trying to repeat myself but if I was the OP I just wouldn't do anything that I wasn't comfortable doing considering all factors.

[n8hutch]

Ken i wasn't saying that you didn't think a coupala could be offset, that wasn't my intention anyway. It's all good. Just posting a couple pics to give the opportunity some ideas. I guess I am just a little too old Fashioned, I like to think that if people put their Mind to it and study enough they can figure a way to do things on their own and do what works for them . I just feel like we live in a you can't do this or that society. I'm a can do kinda guy even if its wrong sometimes. I am sure Calvert brothers can figure out a way in the end to build a safe loft.

[Bucket Head]

Late to the party here, so I only offer this for comparison. I had originally planned to put my head tank in the loft. Went another route, but anyway, the attic trusses were designed and built by a engineer at a local truss builder, not by just anyone or by an online calculator. I had acquired a small bulk tank and wanted that upstairs. Didn't know the size but the engineer wanted the exact capacity and its weight so the "load" determination could be made. So I measured a lot of water and determined it was 200 gallons. Not very big and much smaller than some of the overhead tank sizes I've seen. The load/tank was engineered to be center of the sugarhouse (it's 24' wide) and I have two sets of three married together trusses, 2x10's, on 24" centers where the that tiny tank was going to be! The tank is about 4'x4', so a total of eight trusses were going to be directly under that weight. Over engineered? Can't say but not according to them. Plenty safe? Probably. Better to be safe than sorry? Absolutely. I didn't want my roof looking like a sway back mare because of incorrect load distribution!

Steve

[maple flats]

As you calculate the weight, factor in the wt at the highest % sugar you will RO to, not just for 2% sap, Then get a structural engineer to design it.
I've never put a head tank in a loft, but my raised platform for my head tank outside, on my north wall was designed to hold a 415 gal milk tank. It has 4 posts, set 4' deep, on concrete pads , 1 under each leg of the tank, then the floor was just pressure treated 2x4's flat and resting on 4x4 treated lumber spaced 16"O.C.
Don't be penny wise and pound foolish on supporting that much weight. Do it right or your widow could be all alone.

[TapTapTap]

The 24 ft roof span desired by Calvert Bros can work nicely for attic trusses. That span certainly works with heavy timber rafters and dimensional lumber rafters but the length and sizes start to be costly and challenging to install without lifting equipment. I agree with Buckethead that the truss supplier will design the roof for your loads. And, I don't think there would be an extra charge for engineering since most truss suppliers custom design every order. The upcharge would be for additional trusses or heavier members. You could even transition to the rafter design over the evaporator room for a more open and traditional look. And, no posts needed in the middle of your building.