Another mill shed, but with a beam question....

[MotorSeven]

Since i built the extenstion for the LT15, I had to make a beam for the front of the mill shed. I cut and skidded a 29' poplar log, and milled it to 28'(as far as the mill would go) finishing the 4 cuts with my 361. It's about 11x11"'s centered over the heart.
I plan on spanning about 28', am I nuts?

Oh and I got to use my new 60" Logrite peavy...wow, what a nice tool!













RD

[backwoods sawyer]

Are you planning any bracing to shorten the span? What kind of snow do you get in your area? I am not an engineer, but for the size of roof that you will be supporting, the fact that it is an out building, I would be inclined to think that you would be ok with it. If it tends to sag a bit you can always add a removable post to help carry the load.

[MotorSeven]

Yes, Knee braces on each end. Less than a foot of snow average. Roof will be 14' wide, tin on lathing & I will pitch it as steep as I can.
I hadn't considered a removable post...thanks!

RD

[beenthere]

If this is a clear span of 28' under the beam, you will likely need something above it to hold up the middle (or support posts below it to do the same thing).

I'd be surprised if the beam would support itself over time, just supported at the ends.

Can you build a truss over the top of it, like a gable end?

[MotorSeven]

I could do a truss, but was hoping to get away without one........... ;)

RD

[Jasperfield]

You can use posts on your rebuild. Your present design will fail.

The beam not only has to support its own weight, but at least half that of the entire roof structure, the tin, and 6+ inches of wet snow.

I believe it would be much cheaper to revise now rather than later.

[bandmiller2]

I've never used poplar isn't it a light brittle wood??When ever I have to carry a load over a span I use oak preferably white,it may bend but won't brake.You could truss your beam with wire cable and turnbuckles attach at each end with a block in the middle.Make up a good support post for the middle when expecting snow put it under.Frank C.

[MotorSeven]

Would this be better: I split this beam into 3-3 & a half inchx11 boards, turn the grain opposite, then put 2 - 3/4 plywood strips alternating the ply joints the entire length & screwing thm all together in a sandwitch?.  So I would have: 3.5 "Pop, ply, 3.5pop, ply, 3.5pop...= a 11x12" "laminate type beam. I thought about the temp post, but I am not liking the idea of removing/installing it every time I mill.

RD

[Warren]

MS,

I am not an engineer, so my comments may be worth what you pay for them... ;D  But, without some serious knee bracing/trussing, I don't think you will be happy with the result.  My understanding is that you get much better vertical loading on a long horizontal span by adding to the height of the beam, versus thickness.  Since you have a serious chunk of poplar, if you choose to resaw and laminate with plywood, you might want to consier making the final dimensions taller, and not as thick, maybe 22"x5.5" etc.  Will still need the knee braces, but better vertical loading.

Or, take a look at other ways to "skin the cat",  Such as, how 'bout a 28 ft long shed with an 8 ft cantalevered over hang over the saw ?  This would give you zero posts to block moving materials onto or off the saw ? I think Arky did something like this to one of his mills at one time.  Might even be pictures posted somewhere on the Forum...  But not for sure...

Given the sharp job you did on the mill extension, I have confidence you will arrive at a similarly suitable solution for your mill shed as well.

-w-

[beenthere]

Would this be better: I split this beam into 3-3 & a half inchx11 boards, turn the grain opposite, then put 2 - 3/4 plywood strips alternating the ply joints the entire length & screwing thm all together in a sandwitch?.  So I would have: 3.5 "Pop, ply, 3.5pop, ply, 3.5pop...= a 11x12" "laminate type beam. I thought about the temp post, but I am not liking the idea of removing/installing it every time I mill.

RD

Yes, it would be "better".  Good enough?, I doubt it.

But, might be you will want to try it, and feel better knowing first hand if it will work...or not.

[MotorSeven]

Thanks for the replies. I will ponder everything today while this storm pummeles us with rain >:(
W-cantalever is a good idea, but it won't fit...I'm backed up to a creek w/ a levee running it's length.
Steel is another option. My local steel supplier has some special ordered trusses that never got picked up...waiting for a price. I also have here on the farm a few 40' 12" bridge I-beams. This would be overkill and a wast of a premium bridge beam....but...it's here and was free.  Hmmmmm..........

RD

[Bruce_A]

Use roof flashing under that plywood with 2-1-2 nailining schedule to 5".  Will really increase the strength and doesn't cost an arm and a leg.

[Papa1stuff]

MS , If you don't want to use those 12" beams ,I would be glad to come and get them! ;D ;D

[MotorSeven]

"MS , If you don't want to use those 12" beams ,I would be glad to come and get them!"

No way...I'm hoarding thos babies! :D

[moonhill]

I must say I would go with the cantilevered idea.  Putting braces on the ends will help with the racking but won't do much with the load, 28' is just a long span with out some support from above or below. 

If you had a second or even a third long timber you may try stacking them with shear keys in between them, you may want advice from an engineer even at that.  Scroll down to page 655, some other interesting examples as well. 

http://books.google.com/books?id=e1swAAAAMAAJ&pg=PA653&lpg=PA653&dq=wooden+keyed+beams&source=bl&ots=04g64ycekB&sig=iSHo66zNSWqDY0brawwqO7NH6aE&hl=en&ei=DbG-SsKhHpPU8QaF7aGpAQ&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=wooden%20keyed%20beams&f=false

Tim

[Hilltop366]

If I remember correctly when you double the width of a beam you double the load it can carry,

if you double the hight it will be 6 times the load it will carry.

I'm thinking a few flat trusses on the open side of shed (boxed in with plywood), and one running down the ridge
(it can be much taller where there is more room)

[mike_van]

RD, I also think this plan will fail. Better options are found by searching google for 'open span building' 'plywood rigid frame' a quick search came up with this from North Dakota    http://www.ag.ndsu.nodak.edu/abeng/plans/Construction1.htm

[bandmiller2]

RD Moto,28' is a tall order for any wood beam corner braces each end can get it down to 20'.Two short heavy pieces of angle iron at 90 degrees on the top end of the beam.cable run down to the middle block below the beam,on each side.Turn buckles to preload the beam,in outher words the cables carry alot of the load and the beam is more or less a spreader.The post in the middle I mentioned is only for when you expect a heavy snow load or your not going to use the mill for a wile.Frank C.

[Papa1stuff]

"MS , If you don't want to use those 12" beams ,I would be glad to come and get them!"

No way...I'm hoarding thos babies! :D

:( :( :( :(

[MotorSeven]

Ok guys, I am going to go with steel. I'll update when I decide Beam or truss, and if doing steel I "mise well" go with a bigger mill shed right?  8)

RD

[Papa1stuff]

Bigger is better smiley_swinging_board

[clif]

I do not know how to link this, but you might look at posts titled "Timber framed small plane hangar" here on the FF.
ps how do I post a link?

[mike_van]

Large jet airplane hangar might have enough room. Might I said!  :D

[moonhill]

My building has 2, one on each end, aircraft hanger doors, 30'x16', they bi-fold.

http://www.bifold.com/

This is not the company I used but it does show a wide use of the door, I did not see mill buildings as an example.

Tim

[shortlumber]

I realize you have made your decision, but I'm sure others will read this.

It would take a 10x16 structural select (the best of the best) in poplar to make that span at a 40psf load.

Knee braces nailed to the post do make a significant difference as does using a 3+ ply built-up girder.  

Steel is the only sensible way to go on this one.  

[Frickman]

Almost every mill in my area that has a log deck opening over sixteen feet used steel. I bought a heavy I beam from a friend who tore down a local school. I think he charged me five dollars a lineal foot for it back in the 90's. It was the best hundred and some dollars I ever spent.

[Dana]

I wonder if an I beam from a mobile home would carry the span? You could weld both I beams together (boxed) and it would be much stronger.

[ljmathias]

Has anyone looked into a pre-fabbed truss for the larger openings?  I've got plans for making some that range from 30-50' and I was told it's possible to go even longer- thought about doing it for my mill shed but didn't have the money so just used knee braces on a couple of 12-14' SYP logs... seems to be holding up just fine but then our snow load down here is pretty low, like zero

Lj

[MotorSeven]

Ok....I am going to make y'all crazy. I hung the beam today. I thought hard about it, but I just couldn't use steel for my "mill" shed, it did not seem proper. Knee braces and a removable center post. I will pour a small concrete pad for the post, and use a centering pin in the beam. I had some scavenged power poles that were begging to be used. The span ended up being about 26'........I'll post some pic's tomorrow.

RD

[bandmiller2]

RD Moto,good for you,if it tends to sag too much you could always jack it up and bolt two pieces of channel iron on the sides or do the old cable trick.Its not like you and your family are sleeping under it.Frank C.

[MotorSeven]

I need to mill & hang 6 more rafters. I made them 8 quarter x 7"x16'.

[fishpharmer]

You don't play......looking good.   Similar to member ljmathias.  He has some pretty cool looking bracing.  I stole his post and put it here so you can see.  Hope you don't mind LJ ;D.

I am just finishing up a 14X30 shed on slab dedicated solely to the mill.  Built with two SYP logs as beams on the front and back to hold up the rafters and purlins for metal roof.... but then, my snow load is roughly zero.  Works great for cutting- load logs on one side, take off slabs and lumber on the other.



Haven't got pictures of the shed with the roof on yet- bout to put some siding on and that will more or less finish it up on the outside; still planing on hooks, shelves and storage on the inside.  I'll get more pictures shortly.

Good luck.

Lj

[KyTreeFarmer]

Motor7 Great looking shed so far. Can't wait to see the finished pics.

Mike

[MotorSeven]

Ljmathias had a backhoe, tractor FEL and scaffolding???

cheater.......

[ljmathias]

Cheater?  Of coures!  That's what all those toys are for, no?  Besides, they all get used lots of other places= the FEL is my everyday, go-to piece of equipment.  For example, just scooped up a bunch of my son's plumbing trash and dumped it in the truck for a trip to the dump.  This afternoon, we'll pry up and relocate several piles of concrete pieces of various sizes.  Right now I'm about to cut some 2X12's 20' long for stair stingers for my son's family's new house- using a 28" Katrina SYP (special breed of pine found only in the Deep South) and will use what's left for siding for that same house.  Later today, back to the Purvis tire shop to get my tractor tire which I'll unload into the FEL bucket and then position it on the axle for mounting.  I don't know how I'd ever get along without that FEL- like I said, it's my everyday tool for the last 4 years (and you'll never guess how long I've had it...).

Scaffolding was used to put all the rood and siding up on the big barn and on the sawmill shed- priceless!  Sure beats trying to wrestle big metal sheets perched on a ladder.

And the sawmill?  Why lots of beams and siding (inside and out) for my son's new house- a real work of art if it were done by anyone else; with me it'll be "get'er done!" instead of artistic.

Anyone, I'm also formally retired now (as mentioned by others on the forum) or rather half-retired which goes well with the other half which is half-arsed or so...

Lj

[MotorSeven]

and poor ole me with a FEL & ladder ;)

Got all the rafters up. Had to cut 2 Jack pines down, then make 4 trips up the ridge with the tractor to skid them down. While I whittled on the logs, I cut all the lathing(or purlins) for the tin. I pondered how to attach to the existing shed, & it dawned on me to cut a slot in the board on board to access the vertical cross tie post behind it. Lathing tomorrow if the rain holds off & ordering the tin which will arrive on Wed. That gives me a lot of time to knee brace.......

[MotorSeven]

Ok, mill fans, it's 95% done. I am waiting for some 16" log screws to arrive to finish attaching the knee braces, and hurricane straps(I make my own out of the wide steel lumber/pallet bands...most places throw it away).
The tin came yesterday at about 4pm. As son as the truck drove off it really started raining & the wind was up. So, I sat under the drying shed thinking that I would have to wait to hang the steel. After about 20 min, the rain stopped and the sun came out 8). I got all 42' down before dark, while watching a huge black front move up the valley. It rained all night and my mill is dry!













RD

[Slingshot]

Great loking shed. Are you going to enclose any of it or leave all open. I am putting siding on part of mine so
I can park the mill head out of the prevailing winds and blowing rains. Don't want to have to cover it all the time.
Probably still throw something over the engine.


____________________________
Charles

[fishpharmer]

MotorSeven, Outstanding!!

What I nice setup. 

[MotorSeven]

I think I will leave it open, more worried about heat than cold and I want the sawdust in the air to move out quickly. I used jack pine for the purlins and half of the rafters....kind of an experiement since I read so much bad stuff about jack. I just have a zillion big straight jacks that are easy to get to. If it goes nuts, I'll pull it out and put in poplar. 

So, should I pull up a lawn chair, a cooler of High Life and a nice maduro cigar & watch the beam sag? ;D

RD

[schmism]

looks like you got your solution but FYI

I was a truss engineer for 5+ years.   30-50' flat parrell cord "beam" trusses are very common.  You need height but a 3ply 4' tall 2x6 over 2x6 will span span 80+ feet easy for standard loads.

"big" girder trusses were 80'ers carrying 1500+ lbs per lineral foot.  (those got special foundation support notes due to the 60,000 lb supports required.)

[fishpharmer]

I was a truss engineer for 5+ years.   30-50' flat parrell cord "beam" trusses are very common.  You need height but a 3ply 4' tall 2x6 over 2x6 will span span 80+ feet easy for standard loads.

I am obviously no engineer.  Schism could you explain further, or show a picture or link.   
Thanks

[bandmiller2]

RDMoto,you might need alot of beer and a whole box of cigars.Good job,sometimes you just have to do something and trust your gut feelings.Its a good feeling to hear the rain coming down and know your mill is dry.Keep the shed open to disipate exhaust and dust.Machinery buildings should be either open with good ventilation or closed and insulated to keep equipment from sweating with temp change.Wish we were neighbors.Frank C.

[MotorSeven]

Yes Schmism, a visual aid is needed for those of us that are numerically/mentally impaired ;)

RD

[schmism]

ill run one in the truss software and post a pic tomarrow.

[379hammerdown]

Another good way of carrying a long span is with 2x12's and the rolls of flashing. A friend of mine has 30' spans like this in his large barn, they don't bow one bit. Even after two hurricanes!

He made his with a supply of 16' 2x12's to make the 30' beams. laid down two 16' boards, rolled the flashing over the length, then laid a 16' in the middle and two 8's on either end, to make sure the splices were far apart. Then he fired several nails through the length of it, flipped it over and did the same to the other side... then drilled & put some bolts through every few feet to make sure there wasn't any separation. Then fired lots more nails through them, Trimmed them to length and viola!!!!!!! It wont bend at all because the metal sandwiched in between cant wrinkle. They are super strong!

That's my suggestion.....  8)

[MotorSeven]

I've heard of the flashing thing & would like to try it sometime. It sounds easy and interesting.

RD

[ljmathias]

Wouldn't good wood adhesive do the same thing?  I recall a Popular Mechanics or Science article awhile back that concluded something like, if you glue and screw OSB or plywood to a stick frame, structural strength goes up by 2 or 3 times, but I could be wrong on that (memory is the second thing to go....).  The argument went something like this: failure at a nail or screw involves up and down (back and forth) motion that compresses the wood near the fastener and loosens the fastener in the wood- gradual pull out and failure.  Adhesive stops that initial motion so that the fastener maintains its full holding power.  Make sense?  Anyway, that's how I built a couple of long beams: 2Xsomething wide staggered as mentioned above but with PT plywood cut to width, glued both sides to the lumber, all nailed and screwed and/or bolted together to make everything tight so that everything works together.

I still think an engineered truss is a better way to go, just costs more.  I love the way the trusses in my big barn support across long spans, and the ones in my son's house are incredibly strong in terms of weight bearing ability.  In short: wood is good.

lj

[MotorSeven]

Just wanted to update the status of my mill shed main beam. It's been about 14 months & it still has that slight upward arch to it in the middle and does not appear to have settled/sagged at all. I never did have to put in a temp center brace....I guess I got lucky eh? 8)

[Jasperfield]

 



This is a TF shed I designed & built in October of 09. It's inside dimensions are 18' X 40'.

[Jasperfield]

 



Another view showing the cantilever overhang.

[barbender]

That's a beautiful shed! Too beautiful, nice looking work.

[redbeard]

I like your design on the cantilever, I have a similar bld. but without the cantilever,That would work good on mine. Good job!

[Woodchuck53]

That's a good looking shed. What's that covered up with snow behind it? What kind of wood is it? Great pictures too.

[MotorSeven]

Jasper...very nce, make mine look...er...ahhh...rustic? :D

[Jasperfield]

It's white pine.

The machine is a firewood processor resting from the previous summer and getting ready for this past summer and fall.

[metljakt]

Anyone need engineering calcs?

[MotorSeven]

What Da heck is up with all Da "Da's"?
I think we have been hacked by a member of the "Fatherland"!

[ScottAR]

Appears to be Yooper night...

[redbeard]

Okay I will ask what Da heck is a Yooper?

[Don_Papenburg]

Jeff when he is hunting