Laminating 2x6s for pole buildings

[SuperCobra]

Thinking about laminating 2x6s for a pole run-in shed. Would seem to be cheaper than buying 6x6s, straighter, and a wider range of lengths.

So what do people use to hold them together? I have a nail gun so would rather use that and construction adhesive (if needed).

Assuming codes don't apply, what have you seen used? I'd rather not spend a lot of money in hardware (carriage bolts, lags, etc.) if I don't have to but I don't want it delaminating a fews years from now.

In other words, is the newer pressure treated wood really as corrosive as the inspectors would lead you to believe?

 

[Duffster]

Nails and glue. You do need hot dipped or stainless.

 

[carpenter383]

Thinking about laminating 2x6s for a pole run-in shed. Would seem to be cheaper than buying 6x6s, straighter, and a wider range of lengths.

So what do people use to hold them together? I have a nail gun so would rather use that and construction adhesive (if needed).

Assuming codes don't apply, what have you seen used? I'd rather not spend a lot of money in hardware (carriage bolts, lags, etc.) if I don't have to but I don't want it delaminating a fews years from now.

In other words, is the newer pressure treated wood really as corrosive as the inspectors would lead you to believe?

I have seen this on multiple pole buildings and we just recently built one using this method. You need to use double treated 2x6's in the ground. The standard treating is not meant for underground use. Anything above ground (and out of the weather) obviously does not need to be treated. Laminating posts is a good way to avoid twisting and warping of a typical post. We just nailed the 2x6's togeather without any glue, but using glue would be a good idea and couldn't hurt anything. Just keep each 2x6 staggered from the next one a couple feet and you should be fine.
This also makes it easier to build headers into the posts because you can cut each 2x6 to the specific length you need by subtracting 11-1/4" on the outsides for a 2x12 header over a garage door or 5-1/2 for a 2x6 over a window etc.

 

[SuperCobra]

Thanks. I take it I won't find "double-treated" boards in the deck section of Home Depot or Lowes. I've heard of rating like .60 something and .40 something or lables like "burial' or "direct ground contact."

 

[MikeInEburg]

Yes, "direct ground contact" is what you want. I made the same decision recently and ended up just using 6X6 posts - found it easier than trying to laminate my own.

Mike

 

[Kays Supply]

On my pole barn they left the center 2x6 short and put the truss in the pocket. They then cut the outer 2x6s flush with the truss. It made a really neat and strong setup.

 

[EddieWalker]

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

 

[JDeerekid]

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.

 

[QRTRHRS]

Glued and splined 2x6's etc. have been available for years with the end meant for the ground being treated. Prior to ACQ treated lumber, .40 retention was for surface contact only if that and .60 on up for inground. I have not kept up with the ACQ aspect other than it eats fasteners so use really high quality. I also do not think that ACQ uses the same rating system.

A few years back, I delivered pole barn material for a large builder that also had a Perma Column franchise. For there own use or customer demands (the customer could purchase only the Perma Columns) they would simply air nail 2x.. non treated stock together with no glue. This method was advised by Perma Column from what I know.

I think you could laminate your own posts using varying lengths of treated. Don't forget to put some blocks on the lower part for uplift resistance. Pre drill the treated especially on the uplift blocks to minimize cracks. An email to the fastener manufacturer about the below ground application would be beneficial. The truss pocket is a good suggestion.

 

[mcd176]

Eddie,

Just FYI, Morton buildings use the laminated 2x6 method on all of the pole buildings around here, My office just had Morton build a 50x100x14 building and thats how they did it.

 

[EddieWalker]

Yup, Morton is the big name who's doing this. Has anybody checked to see what the rating is on those 2x6's?

Something I never even doubted was that they wouldn't use glue. Three seperate boards that are nailed together will never come close to a solid piece of lumber of the same size. Three 2x6's that are glued together their entire length would create a post that is stronger then a solid piece of lumber. I don't know how much stronger it is, but know that laminated rely on glue and layers to create their great strength. Just nailing the boards together will spread the load between the boards, but each board is still functioning as an individual board. The nailing just holds them together, but doesn't make each of them stronger a a whole like glue would.

If I was to do this, I would glue them the entire length and screw them together with 3 inch screws in a pattern to ensure a tite bond. The pattern of screws would also contribute to achieving maximum strength from doing this.

Eddie

 

[Kays Supply]

The barn I had built with the 2x6 posts was only a 20x30. The 40x80 ,I put a foundation and 2x6 on 24" centers. It only took 2 more 2x6s per 10' to do this. No ground contact at all. That building took the Southern Illinois wind a few months back that took out several pole type buildings. I can isulate and close it in easy later.

 

[smfcpacfp]

I am having Cleary builders build a pole building for me right now. They laminate 3 2" by 6" using nails every 4" with no glue. Their research claims that the laminated posts are 1.5 times stronger than a 6" by 6". I can see how this would be possible and how a laminated piece of wood would stay straighter given that you have 3 different grains connected to counter balance any twisting or warping action.

Here is a link to their write up of their posts:

http://www.clearybuilding.com/feature_PDFs/THE_CLEARY_COLUMN.pdf

 

[EddieWalker]

Interesting link to Cleary and the test results. Obviously, the full length laminate is stronger then the solid 6x6 when laid on it's side and supported 16 feet apart. Two obvious questions jump out at me. Why test it like a bridge when a post is designed for supporting a load vertically primarily and withstanding side loads from the wind when distributed across the wall. It seems like a very misleading test that ignores the job of the post.

My guess is that a test was done to see which was stronger, and they chose not to share those results. Whey they chose to show the results of a bridge, or loading a post on a span is beyond me. Who cares? It's meaningless and irrelevant.

If they use the proper treated wood, then it really doesn't matter. Three 2x6's is going to be plenty strong enough to do it's job. I just don't plan on doing it that way myself on any of the jobs that I do. I probably charge more then they do too, but my clients pay that premium to get what I provide them. It's not better, it's just another way to get the same results. The difference is what some people are willing to pay for, and I'm willing to provide to them.

One thing that just came to me while looking at that charts was the likelyhood of moisture being trapped between the 2x6's. With the additional surface area, it would make sense that rot would be an even bigger concern. Glueing the boards together would seal out moisture and add strength.

Eddie

 

[tommu56]

My the pole barn at my cabin has factory manufactured laminated posts the taller ones >16-18 ft are not treated in the top section the they are all syp even the top and the glue lookss like gorilla glue type.

The other issue is if you cut a 6x6 the center is not usually a full treatment.

The 2x6's are treated before laminating and solid green to the center.

tom

 

[Duffster]

The other issue is if you cut a 6x6 the center is not usually a full treatment.

The 2x6's are treated before laminating and solid green to the center.

tom

Bingo

 

[firefighter jim]

We've always used solid 6x6's and 4x6's in the pole buildings that we had built on our property. However, I can see one benefit of the laminated posts in that each board being laminated has a different grain structure which may aid in prevented the post from warping and twisting (very common in pressure treated lumber).

 

[EddieWalker]

...The other issue is if you cut a 6x6 the center is not usually a full treatment.

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

 

[dave1949]

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

I've seen them here, always bothers me a bit too. I guess they just aren't doing a thorough job in the pressure treating process. I would want some good, solid dimensional lumber to build laminated anythings. That's not always easy to find these days at your local lumber yard.
Dave.

 

[J_J]

Here is a good idea, maybe.

3 Ply 6" Laminated Column | PERMACOLUMN