Sawmill Shed Pole Building

Don P · November 27, 2020, 09:18:38 PM

Big beams is braggin rights ;D
Those are 60' tulip poplar (a weaker species) 12x12's across the tops of the log cribs, that center span is 18'
The tributary area loading those is about the same as yours but my design load is around 10psf higher, snow. The section modulus of those (geometry for bending strength) is 288"³, For your 6x16's it is 256"³. I was having a, uh, discussion with the timberframers who were doing the work here. They were wanting to use 8x10's if I remember right. In mid harangue an engineer friend of mine happened to stop by to see how it was going. I had him do some cyphering right there on a timber as we sat there. He finished and said "You're cutting it pretty fine, I'd have used a 12x14".

Furby is our double secret member

. Yes we were thinking in edge, it would take some special joist hangers to get the purlin heights to align but they are readily available.

Umm, I just caught what you are thinking, 5' is a long span flatways, Personally I'd run the purlins up on edge, but it isn't really a failure concern where you are.

TimW · November 27, 2020, 11:26:19 PM

Quote from: Don P on November 27, 2020, 09:18:38 PMBig beams is braggin rights ;D
Those are 60' tulip poplar (a weaker species) 12x12's across the tops of the log cribs, that center span is 18'
The tributary area loading those is about the same as yours but my design load is around 10psf higher, snow. The section modulus of those (geometry for bending strength) is 288"³, For your 6x16's it is 256"³. I was having a, uh, discussion with the timberframers who were doing the work here. They were wanting to use 8x10's if I remember right. In mid harangue an engineer friend of mine happened to stop by to see how it was going. I had him do some cyphering right there on a timber as we sat there. He finished and said "You're cutting it pretty fine, I'd have used a 12x14".

Furby is our double secret member . Yes we were thinking in edge, it would take some special joist hangers to get the purlin heights to align but they are readily available.

Umm, I just caught what you are thinking, 5' is a long span flatways, Personally I'd run the purlins up on edge, but it isn't really a failure concern where you are.

Double pen dogtrot. smiley_clapping I love it!

Johnny Jet would too. smiley_chop Furby too. poston-smiley I got a dragon for a friend.

My barn has 5 foot truss centers with flat 2x4 purlins on two foot centers. Works fine

and gives a solid feel underfoot while walking dancing-jack on the 22 gauge tin.

TimW · December 10, 2020, 12:03:54 AM

I picked up, what I thought would be Pine today. It was hard wood. One Red Oak, looks nice enough to cut 2x12s 20 footers. Can I use Red Oak for the top sill plates, along with the SYP?

Don P · December 10, 2020, 07:56:48 PM

Yes,
I can hear the howls already but the guys that bend and break wood for a living know more than we do. It is weaker and less stiff than SYP. It would still pass in #2 or better. Green oak is acidic and corrosive to fasteners, use HDG stuff, hot dipped galvanized, which is a good idea anyway.

TimW · December 11, 2020, 02:44:08 AM

Quote from: Don P on December 10, 2020, 07:56:48 PMYes,
I can hear the howls already but the guys that bend and break wood for a living know more than we do. It is weaker and less stiff than SYP. It would still pass in #2 or better. Green oak is acidic and corrosive to fasteners, use HDG stuff, hot dipped galvanized, which is a good idea anyway.

Thanks. Galvanized fasteners. Got it. What about White Oak?

Don P · December 11, 2020, 08:02:38 AM

White oak is slightly stronger than red but is less stiff and slightly less strong than SYP. Northern red oak is the highest in allowable design properties of the oaks. White oak, well all the oaks have the tannic acid corrosion problems when green. When used dry I haven't seen issues but a shed is probably going to see condensation on fasteners so galvy is a good idea.

Last night when I got a pass with oak I was plugging in full dimension 2" x 12" using 2 sticks for each plate, so a 4x12 total, adjusting the numbers up 10% for multiple members and 15% for short duration (wind).

After a pm exchange with beenthere last night I was curious. When I go back to the original average strengths from testing at the Forest Products Labs, chapter 4 in the Wood Handbook. Real quick comparison, not a in depth stare, there's lots there. The average strength of all these is pretty much in the same range, read that with real caution. You are fine if used as above, this is just more background. When I get to the allowable design values published in the NDS, the reference we use in construction, the allowable design values developed by using factors of safety etc from procedures specified in an ASTM standard, the design values spread more. In the NDS they are grouping species and using the lowest strength specie in the group to give allowable working stresses. From your first question I used the group "mixed oak" which is any oak graded under the NeLma rules. One comment from the instructor in grading class was that Dougfir and SYP are the most tested species and because of that better knowledge we have more confidence in their performance and can confidently assign them higher allowable design values. That doesn't mean though that it is wise to bump the oaks on our own, we don't have the bend and break testing experience to make that inference.

TimW · January 15, 2021, 11:07:51 PM

My land clearing guy came through for me and asked me to come pick up some huge logs. These are all over 21 feet.

The largest butt is 37 inches across.

The Lull handled them and some two at a time with ease.

I love the Big ol Lull.

These logs will be for 20 foot full dimension 2x12s for the shed top sills. Also two will be 6x16 beams.

Magicman · January 16, 2021, 08:31:04 AM

Congrats on the logs and da Big ol Lull, da Bull is looking good!!

TimW · January 16, 2021, 11:29:34 AM

Quote from: Magicman on January 16, 2021, 08:31:04 AMCongrats on the logs and da Big ol Lull, da Bull is looking good!!

Thanks Lynn! I like it............BULL!

scsmith42 · January 16, 2021, 11:40:16 AM

Something that I'm curious about... what do you plan to use the wide door for on the side of the building?

TimW · January 16, 2021, 11:58:57 AM

Quote from: scsmith42 on January 16, 2021, 11:40:16 AMSomething that I'm curious about... what do you plan to use the wide door for on the side of the building?

Convenience. Nothing gets my goat more than having to move something to get something else out. I like lots of space while working. I hate working around clutter. If I got a huge project (say timber beam trusses) going on at one end and the sawmill at the other end, something would have to be rearranged with out side doors, to work on a machine or truck. This way, my heavy equipment toys can have their own spot without moving pallets or lumber or such. I do want them under cover, as all good farmers build sheds over their tools! :D

TimW · January 27, 2021, 10:29:38 PM

I tore into one of the huge SYP logs today. I was able to get one 6x16 beam and five 2x12 top plates out of it. It took me all after noon. One it was on the mill and dogged, I couldn't turn it as the side on bottom was somewhat concave. So I cut one side and rotated it with the Mahindra's grapple. The straps make it a lot easier to move than clamping the grapple around it.

I thought it was spotless with knots until I saw this photo on the computer. Looks like 3 small knots.

farmfromkansas · January 28, 2021, 10:30:53 AM

Wow, that Lull would make building easy. Have you considered going 10' centers on your trusses instead of 5'? Morton buildings does that, and uses 2x6 nailers on edge to span between. Takes heavier trusses, but much less heavy plates. They use 3 -2x's and put the truss in the center of their poles, poles are laminated. What I find interesting, is how they wrap their buildings with steel straps as wind bracing. We get a lot of wind in Kansas, and I have heard of no Morton buildings getting blown down in my neighborhood. Not a salesperson for Morton, there are other engineered wood buildings that are well built as well.

TimW · January 28, 2021, 11:07:29 AM

Quote from: farmfromkansas on January 28, 2021, 10:30:53 AMWow, that Lull would make building easy. Have you considered going 10' centers on your trusses instead of 5'? Morton buildings does that, and uses 2x6 nailers on edge to span between. Takes heavier trusses, but much less heavy plates. They use 3 -2x's and put the truss in the center of their poles, poles are laminated. What I find interesting, is how they wrap their buildings with steel straps as wind bracing. We get a lot of wind in Kansas, and I have heard of no Morton buildings getting blown down in my neighborhood. Not a salesperson for Morton, there are other engineered wood buildings that are well built as well.

Yes, the "Bull" is making life easier here.
No, I am firm and set "in my head" on 5 foot trusses. That is where the building prints are, in my head. Bare in mind the 6x16 beams are just for door header support to the 2x12 top plates. Two beams with two doors.
Besides, have you ever walked on a 2x6 flat, supported at each end of ten feet? It will bow and flex. My barn has trusses on 5 foot centers with 2x4 purlins spaced two feet apart. That spacing is rock solid. I don't like springy when I walk on a tin roof.

farmfromkansas · January 28, 2021, 12:26:51 PM

The 2x6's are put on edge, you would use the 2" side for fastening your metal. Much stronger than flat laying boards. They use joist hangers and put them flush with the top of the trusses, leaves less area for birds etc in your building.

TimW · January 28, 2021, 09:33:41 PM

Quote from: farmfromkansas on January 28, 2021, 12:26:51 PMThe 2x6's are put on edge, you would use the 2" side for fastening your metal. Much stronger than flat laying boards. They use joist hangers and put them flush with the top of the trusses, leaves less area for birds etc in your building.

Thanks for clarifying that. Sounds like a lot more work than what I used before and know that it works. Cost too. Have your priced joist hangers lately?

farmfromkansas · January 29, 2021, 12:29:33 PM

Just a different way of building a building, but they are a very strong long lasting building. Most people do not have a Lull to put up the heavy trusses.

TimW · February 01, 2021, 01:53:23 AM

Quote from: farmfromkansas on January 28, 2021, 12:26:51 PMThe 2x6's are put on edge, you would use the 2" side for fastening your metal. Much stronger than flat laying boards. They use joist hangers and put them flush with the top of the trusses, leaves less area for birds etc in your building.

I have been trying to wrap my head around how you would use joist hangars to secure purlins. I think you meant these.

We call them hurricane clips down here.

TimW · February 01, 2021, 01:54:51 AM

Quote from: farmfromkansas on January 29, 2021, 12:29:33 PMJust a different way of building a building, but they are a very strong long lasting building. Most people do not have a Lull to put up the heavy trusses.

That is one of the reasons I bought a telehandler.

Don P · February 01, 2021, 07:33:04 AM

No, that method uses a joist hanger with the purlins set flush between the trusses.
Lika so, @ 2' centers I'm coming up with 528 hangers going that way ;

Mike W · February 01, 2021, 10:00:03 AM

Yes, those are H-1 hurricane ties, usually for tying the rafters or trusses to the top plate for uplift. Think they were trying to explain more of this system:

These are 40' trusses at 12' o.c. the purlins are 2x8 at 24" o.c. with 2x8 joist hangers (a bunch of them) they are only $0.65 each, so not a bank buster.

TimW · February 01, 2021, 11:41:20 AM

Quote from: Mike W on February 01, 2021, 10:00:03 AMYes, those are H-1 hurricane ties, usually for tying the rafters or trusses to the top plate for uplift. Think they were trying to explain more of this system:

These are 40' trusses at 12' o.c. the purlins are 2x8 at 24" o.c. with 2x8 joist hangers (a bunch of them) they are only $0.65 each, so not a bank buster.

As of last October, Lowes had them for $2.47 each. I just checked online and I can get the cheap ones (two holes per side) for 88 cents each online. But for over 500 needed, I wonder the shipping cost? Thanks for your input.

TimW · February 01, 2021, 11:59:08 AM

Quote from: Don P on February 01, 2021, 07:33:04 AMNo, that method uses a joist hanger with the purlins set flush between the trusses.
Lika so, @ 2' centers I'm coming up with 528 hangers going that way ;

Thanks Don! A picture is worth a thousand words. Now I understand. I was thinking on edge on TOP of the truss. I'm guessing one would still need diagonal bracing with this method. Truss to truss. With all those joist hangars, do you need to add more bracing for hurricane winds?

doc henderson · February 01, 2021, 02:15:21 PM

the nice thing is typical fiberglass insulation could go up there if you wish. it (the purlins) will add some rigidity, but you would still do a diagonal bracing for twisting so it does not fold itself up. rectangles bad! triangles good! you may have one, but for construction like that with forks on the lull, it is still a nice thing to put a work platform on the forks. I have an old alum. truck loading ramp. it is 3 x 11 feet, and I fabbed clamps on four points so I can walk on the ends with fear of it tipping. i can load 4 x 8 materials at the back leaning against the back of the forks.

doc henderson · February 01, 2021, 02:23:18 PM

here is a pic of my joist hangers, single and double for a beam. I bet the price has gone up. this is the underside of my loft where I stack wood in the shop.

you should use the recommended fasteners as well, to have the prescribed rating. My alum. loading ramp is on a trailer so no pic, but given your profession and experience, I am sure you are familiar with those.