Laminating 2x6s for pole buildings

EddieWalker · Nov 9, 2009

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 · Nov 9, 2009

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 · Nov 10, 2009

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 · Nov 10, 2009

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 · Nov 10, 2009

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 · Nov 10, 2009

tommu56 said:
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 · Nov 10, 2009

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 · Nov 10, 2009

tommu56 said:
...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 · Nov 10, 2009

EddieWalker said:
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.