Making a Glulam Beam


Old 03-21-05, 09:16 AM
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Making a Glulam Beam

I am rebuilding a patio cover that had too small of a beam (4x6) that was used and it is beginning to crack and bend. I calculated the loads and for the 16 ft. span, I need a 4 x 10 beam. Has anyone tried to make their own beam, like a pre-manufactured Glulam Beam? Watching some of the do-it-yourself shows, it did not look difficult. Any tips?
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Old 03-21-05, 02:23 PM
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Personally, i would buy one. Building a chest of drawers looks like a 1 hour job on tv too.
Old 03-22-05, 06:01 AM
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LOL, TV is full of "great ideas" but when it comes down to real life the cost and time ratio will far exceed what it'd really take to just buy one, especially as small as yours is.
Old 03-22-05, 06:53 AM
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When you say you saw glue-lam beams on diy shows do you mean saw them being built or used?

I had tried to purchase to a pair of these for a 50' long outdoor foot bridge, and was told that there was no such thing as an exterior grade glue-lam, at least by the company I talked to.
They even refused to give me any info or sizing after they knew what I wanted them for.

I had plans drawn up to build a set but found some steel and went that way instead.
Old 03-22-05, 01:25 PM
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Good point Greg. Now that I think about it, I've don't recall ever seeing a glu-lam in an exterior application.


Why a glu-lam -- either one you buy or one you make? Why not just buy a 4X10? Keep it painted or otherwise sealed, and it'll do fine. And it can't delaminate.
Old 03-23-05, 09:56 AM
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We may be getting lost in terms - I saw and was thinking about taking (5) 2x4's (other than a pre-engineered beam), gluing and screwing them together to make my beam. Cost? My understanding is that full length boards do not have to be used and in my area, cost averages about $210 each (not including delivery). I was just trying to save a little money.
Old 04-05-05, 03:35 PM
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DIY Glulam

A couple of notes on the subject. Glulams are designed using "stress rated lumber" such as used in wood truss manufacture. Also Boise Cascade makes cedar glulams for exterior applications. I hope this helps, if not contact me..
Old 04-07-05, 11:02 AM
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DIY glulam

There are some things you can attempt to do yourself. And there are some things you should never do. This idea crosses over into the realm of things not to do.

Unless you are an engineer, I would advise against designing your own glulam. Even an engineer would not bother to do so.

Exterior-rated glulams do exist. They are primarily used for applications where people want an exterior beam that can be curved, i.e. for architectural reasons.

I'd say just go with a pressure treated lumber or redwood for your deck. Any exterior-rated glulam requires too much maintenance. Engineered products generally don't work so well in exterior applications, as the glue doesn't hold up in the rain.
Old 04-07-05, 09:05 PM
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Making a Glulam Beam is not a DIY project.

First of all a Glulam Beam is not a few 2X4's glued together.
A Glulam Beam is sections of wood(sometimes up to 50+) cut lengthwise and glued together with an epoxy resin compound. This is then placed in a very large vacuum press. When you cut a Glulam Beam you will see that it is not a single solid board but rather (like plywood) several layers glued together. You may find a defect on one side but if you cut through it you find it is only in the top layer and does not go all the way through,as it does in a 2X 4X. These defects will weaken normal boards since they go deep into the board. These defects do not affect Glulams as they are only on 1 layer. Many brands of Glulams are used and rated for exterior projects. As long as the points of entry by screws,nails, anchors and such are treated with a sealant rot and decay is not likely to occur.

One idea that may fit in your budget would be to use a LVL for the span and side dress it with 1 3/4 trim as these are rated for exterior use.

Hope this gives you a better understanding of Glulam Beams

Last edited by majakdragon; 04-07-05 at 10:54 PM.
Old 01-25-14, 09:11 AM
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20 years ago I made an outdoor swingset for my sons that called for making a glued up beam out of pressure treated lumber. 2 pt 2x8, with 1/2" plywood in-between. I just went out and did a pull up on it, it's lasted outside for 20 years. I'm about to glue up a beam for a carport, to make a 25' beam I'm going go use 2 15' 2x10 and 2 10' 2x10, with 1/2" plywood between. I will use liquid nails for the glue. The beam will be covered by the carport roof. If it weren't I'd glue and screw a 2x4 to the top of said beam. Posts will be 1' in on each end of beam, so it will span 23'. If, after I've constructed it, I feel that I need a post in the middle of that 23', I can do that, or I could add bracing from the posts to the beam, and I may do that. I'm not an engineer or architect, this is my own design, but I've got pretty good confidence that it'll work. I wouldn't use it for a bridge, though.
Old 01-25-14, 09:50 AM
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You will definitely need several posts, as 25' is too far for an SFP 2x10 to span unsupported. (See span tables) You would be better off using wider material, getting one single long length of 2x12 delivered to your jobsite rather than having offset seams, as you probably plan to do. Even then, you would still need posts.

When the original poster (9 years ago) mentioned a "glulam" I am sure he was thinking of something like this. In any case, this is not a DIY venture, due to the structural liability involved, not only to you but to anyone in the future. Construction adhesive is generally not recognized as a structural component.
Old 01-26-14, 10:20 AM
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There's still some very pertinent information here, even though the original posts are 9 years old. Probably the most important thing to be learned for anyone considering building his/her own glulam beam is that it's not practical to do so, unless one is equipped with the necessary vacuum press used in glulam's construction. Squeezing the dickens out of individual glued members using a system of multiple wood clamps doesn't come close to having the same effect. A vacuum press enables structural adhesive to actually penetrate wood cells adjacent to the laminations' surface, something not readily accomplished using conventional clamping systems.

Regarding exterior use, glulam bridges were first built about 70 years ago. Although never gaining a great deal of popularity (mainly because they were more expensive than steel or concrete), it was important that correct adhesives were used and proper preservative treatments applied after fabrication. A state highway agency I served a 25-year sentence with learned that lesson the hard way, when upper-level bureaucrats did a road swap with a local city, accepting ownership and maintenance responsibilities for 7 (cedar) glulam pedestrian bridges that had been in service for only 10 years. The glulam members had been fabricated using adhesive intended for interior use only, and hadn't had any preservative treatment applied. We spent almost a half-million dollars correcting all of the deficiencies, using epoxy injection to glue the separating laminations back together before covering main members with shrouding and applying copper naphthanate preservative treatment to everything.
Old 01-26-14, 12:30 PM
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consider a flitch beam - STRUCTUREmag - Structural Engineering Magazine, Tradeshow: Flitch Plate Beams - made my own when we removed bsmnt supporting post for family room remodel 40 yrs ago,,, main floor still doesn't squeak nor does roof ridge sag

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