Laminating 2x6s for pole buildings

[ray66v]

I bought laminated poles that were fully dried before they were made.

The lower sections are .60 retention treated, the upper parts are untreated yellow pine, with finger joints between the two.

When the glue is dry, they lightly saw them, to true them up.

The result is a near perfectly straight pole, with no shrinkage, warping, or twisting.

On a 30 x40 with a loft, they cost me about $200 more than ordinary poles. To me, were worth every penny. Especially, it you plan to drywall the inside, (as this eliminates a common point for big cracks).

 

[dave1949]

Which of these laminations are stronger -
Two 2X6's with 3/4" plywood sandwiched between
or
Three 2X6's

It's not a trick question, I have no idea myself.
Dave.

 

[rus_geek]

Which of these laminations are stronger -
Two 2X6's with 3/4" plywood sandwiched between
or
Three 2X6's

It's not a trick question, I have no idea myself.
Dave.

I think that will depend on the loading. 3/4" has little to no resistance perpendicular to it's surface, but then again, neither does a 2x6. One loading pattern is supporting the weight of the roof, snow, and anything stored in the ceiling. Another loading is wind loads from the side walls. If the building has walls, I wouldn't worry about racking loads, since the side panels will take up a lot of that stress.

One of these designs may fair better in only one of these scenarios.

 

[radioman]

They laminate 3 2" by 6" using nails every 4" with no glue.

Umm - it was my personal belief that anything that anything that is laminated uses glue for full surface contact. Putting nails or screws in something with no glue doesnt count as lamination in my eyes.

 

[EddieWalker]

Which of these laminations are stronger -
Two 2X6's with 3/4" plywood sandwiched between
or
Three 2X6's

It's not a trick question, I have no idea myself.
Dave.

I'm not an engineer, so this is just a guess based on what I do know and as a contractor.

For a post, the thee 2x6's would be stronger. They have more mass and will be able to support a greater load.

For a beam, the plywood will make the 2x6's much stronger and able to span a greater distance with less deflection that the lumber without the plywood.

Adding plywood to a post will not accomplish anything.

Eddie

 

[dave1949]

I'm not an engineer, so this is just a guess based on what I do know and as a contractor.

For a post, the thee 2x6's would be stronger. They have more mass and will be able to support a greater load.

For a beam, the plywood will make the 2x6's much stronger and able to span a greater distance with less deflection that the lumber without the plywood.

Adding plywood to a post will not accomplish anything.

Eddie

That sounds logical to me Eddie. I would guess the plywood lamination would out perform the other when the force is applied against the side/edge of the plywood layer. I have made some of these for beams and have always thought they are pretty darn strong. Never tried it for posts.

I agree with radioman, without glue, you are giving up a lot of the inherent strength of a lamination. The glue should take away the ability of the built up beam or post elements to flex or deflect without actually ripping wood fibers out of the adjacent layers.
Dave.

 

[SuperCobra]

I don't know what research has gone into this, but I have my doubts about using 2x6's instead of 6x6's.

First, I've found that the larger the PT wood, the straighter it tends to be. PT 2x6's are hit or miss on whether they will stay straight, or twist on you. When I buy them, I buy extras because I know a few of them will do something on me. Even after picking through the pile and getting the straight ones, some will still do what they are going to do.

Second, I think that the solid piece of 6x6 tha is notched is much stronger then three 2x6's. I don't know how true this is, and it could easily by to a degree that both are plenty strong enough with an insignificant difference. If you need to support ten thousand pounds, and one will hold 20 thousand and the other will hold 25,000 pounds, then it doesn't make any difference.

Third, I know that posts are treated to a higher degree, or percentage, to be set in the ground. Off the top of my head, there are three basic ratings for pressure treated wood. Outdoor use, like decking is the lowest rating. The next is dirt contact, such as a post set in the ground. The highest rating and treatment is for posts in water. I've never seen a PT 2x6 that was rated for ground contact. On the labels, it will say what percentage of treatment the wood has. Look at the 6x6 and compare it to the 2x6.

I realize that it's becoming fairly common for barn building companies to use 2x6's for thier posts. I would like to hope that they are using them with the rating for dirt contact, but I don't know this for sure. I think the big advantage to using 2x6's is that it's faster to notch the posts. In fact, you don't notch them at all, you just cut the board to length and then attach it again with the space for the notch. When time is money, that's what you get most of the time.

Eddie

Thanks Eddie,
That was pretty much what I was getting at. I haven't seen "ground contact" 2x6s readliy available at a local home improvement store. I was looking for something readily available and convenient. 2x6s would have more length options, easier to transport, lighter to place in holes, etc. However, if the ACQ is so corrosive I need SS fasteners and even then it isn't ground rated, it is not worth the extra effort. However, however, I've seen the plastic sleeves you can put the posts in - that would be an option if I could find them locally - same with permacolumns.

 

[/pine]

[FWIW]
I once had an engineer design a post and beam to replace a bearing wall and he insisted that I support the beam with 4x4 posts rather than multiple 2x4's

 

[radman1]

I would go with laminated 2x6's for the posts. Morton, Cleary, Menards, Astro and about any other newer pole barn shed now uses laminated 2x6's. They are stronger. The added strength is for the wind loads and not necessarily for the vertical loads. I would just go to Menards (or lumber store) and order the laminated posts and not mess with making my own. Then they will be made correctly. They can get about any length you desire. 6x6 square posts may twist, the laminated may have minimal twist but are much straighter and more true overall. I added a lean-too on an existing 60x100x16 pole barn shed this year. The lean-too was 26' in depth. I wanted a front clearance of 13' and pole spacing of 25' for farm equipment. The company/engineers that supply the material for Menards designed the whole thing for the snow loads in my area. The front posts were 4, laminated 2x6s, with 3 laminated, 16" wide engineered lumber beams, 25' long for the headers and 2, laminated 14" engineered beams for the 26' joists which were spaced every 10'. 2x6 purlins every 2 feet between the headers.

 

[QRTRHRS]

Here is a good idea, maybe.

3 Ply 6" Laminated Column | PERMACOLUMN

I forget exactly but these are rated for wind loading at least the same as any post.

 

[buckeyefarmer]

My barn package came with ACQ .60 treated 6x6 posts. Some twisted a good bit before I got the barn finished. One twisted so bad I couldn't use it. And they are not treated all the way through. The company I bought from now uses laminated 2x6's. I would buy them already made, as they are engineered. I like the fact that the roof truss can sit in a pocket, and you can bolt thru it. This makes for a stronger roof. If I was to do another pole barn, I will use concrete footers and permacolumn connectors and remove the ground contact all together.

 

[Rodmo1]

I just finished my garage with the laminated posts. I believe the big selling point for me was the resistance to twisting and the fact that they were treated all the way through. Around here most of the posts I see when crosscut have a very visible center portion which did not recieve much if any treatment. I believe they cost me somewhere around $30 for a 12 or 14 foot length. Very happy with the results. Mine are glued and nailed together. With the price they cost me it probably wouldnt be worth the effort of making your own. Also mine are treated to .60 pounds per cubic foot.

Rod M.

 

[Duffster]

The last time I priced posts the 3 ply 2x6 full length treated with truss plate connectors at the seams (premade) where cheaper than 6x6's in all lengths except 8 footers. The 20' plus lengths where alot cheaper.

 

[EddieWalker]

I just checked my account at McCoys and a PT 6x6x16 is $36. A PT 2x6x16 is $10, so three of them would be $30 for a $6 savings. Of course a 6x6 is actually 5 1/2 inches wide in both directions, but the three 2x6's are going to be an inch thinner on one side.

For $6 more, you are getting about 20% more wood. Figure the price of glue and nails, and your savings is pretty hard to see.

Eddie

 

[newbury]

For $6 more, you are getting about 20% more wood. Figure the price of glue and nails, and your savings is pretty hard to see.

Eddie

Additionally the cost of your time for assembly.
However if you make them like the Cleary Non-spliced Laminated you get 1.5 times the strength.

 

[goatdoc]

You said you are setting trusses into a pocket in the top of the post. What is the spacing of the post. My posts are spaced 12 foot and all have a carrier beam of a doubled 2 by 12 on the top, and the trusses rest on this. My trusses are 24 on center with 1/2in osb or plywood with felt and 30 year shingles on that.

 

[nickel plate]

On the subject of posts and beams you need to also include compression for the post amd tension for the beam.
When laying up a beam for either glue or no glue, build a camber into the beam by laying all members in a crown up position, the longer the boards the better and then cut to size. Spray a paint color on the top edge so when placed you will know to have the painted edge crown up. If no glue is used, address a couple of extra fasteners at each end of the cut pieces and do so after the pencil mark and before the saw cut.
When laying up a post, flip flop the crowns.
In both cases, choose lumber that has no "bullet" showing at each end as that is the most reactionary stick in the unit. These pieces are the actual center of the tree. The further away from the center cut, the less reaction over time will occur.
If you just want to shine this whole multiple board lay up process and use solid timber stock, your lumber yard can special order pieces with a grade stamp "FOHC" free of heart center-no bullets.

 

[BlacknTan]

You can always use this product Perma-Column | Permanent Foundation Systems.

This is what I used for my pole barn. Cost a little more but will never have to replace due to rotting.

This is a great resource!

Thanks for posting this. I think I'll use these for my lean-to shed this year.. There is a distributor close-by also.

 

[Dave5264]

I can't speak for anyplace but here, but I have done several jobs this year with PT 6x6 posts. In every case, they were green all the way to the middle. I have never seen one that wasn't, and would think that would be very odd to find one that wasn't green all the way through. If you have personally seen this, then I believe you. It might be a regional thing, but I find it hard to believe that if they can do it here, they should be able to do it anywhere.

Eddie

wow, wish i could find PT lumber that good, up here I cant even find a 2x4 thats green all the way to the core, let alone a 6x6.