Any opinions on whether to use glulams or lvls for the ridge beam and purlin supports on a simple rectangular structure.
For residential work, you can generally accomplish the same goal with LVLs as with a glulam, but ti is easier to hoist the load into place and bolt several LVLs together in place.
Now if you want a decent looking exposed beam, and like the look of the glulam, go there and find a way to place it.
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DW and I recently went to a meeting at the Freeport Community Center. The meeting room was framed post-and-beam style with 6x6 LVL posts and taller beams, all exposed with black metal fasteners. It looked surprisingly good. The LVL's didn't have the waxy yellow surface, just looked like AC ply.
Thanks for the feedback.What about structural integrity, etc. The longest span is about 24 feet.
"What about structural integrity"
Engineer whichever you decide on to do the job at hand. Any yard that sells either has the software to engineer it if you have the dimensions for them to do calcs from.
There is a difference in weather resistance, humidity resistance, etc. Not normally an issue but could be for pool house, open pavillion, etc.
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From purely a carpenters aspect I prefer LVL's, I can install them one at a time with minimal help if any at all.
Gluelams can require a small army to install.
Woods favorite carpenter
Woods favorite carpenter
or a crane
We haven't used a gluelam for a ridge since I was 14 yrs old, and I am glad for that. It was an experience that I won't forget.
It would have been alot easier with LVL's, we should have used a crane.
I don't think they had invented glulams when I was fourteen...
But I think I'd rather use a steel I-beam
"I don't think they had invented glulams when I was fourteen..."
Just how old are you anyway? Did you start out measuring things in cubits? :)
According to Wikipedia:"The first use of glued laminated timber was in Germany in 1890 by Otto Hetzer. The technology came to North America in 1934. Max Hanisch, Sr., who had worked with Hetzer at the turn of the century, formed a firm in Peshtigo, Wisconsin to manufacture structural glued laminated timber."
LOL, nice history lesson.
Now - when did they come into common practical use?
I thik they hit their stride in the seventies. before that it was, "Hey looka dis Jake. New fangled manmade beams! Think it'll hold up for long?"
I think a lot of gymnasiums and churches were built with them in the 40's, 50's, and 60's; the former for unimpeded space above the playing floor, the latter for graceful high cathedral ceilings. My childhood church was built in 1960 with glulam pillars with gracefully curved knees at about 12 to 15 feet up that became rafters supporting a 16/12 or so roof.
I've also seen a lot of wartime factory buildings with arched trusses where the arch was constructed of laminated, bent 2x stock built up to perhaps 12" to 16". They span a large open floorspaces and I think the curvature may have enabled plywood sheathing to be stiff enough not to need closely spaced supports.
Weyerhaeuser Co. had a production lam beam plant in Cottage Grove, Oregon that was built in the early '60's. I worked there briefly in '73 where most of the production was laying up beams for the caribou crossings on the Alaskan pipeline. It was pretty clear they'd been doing volume beam production for quite a while.
The elementary school I attended in the early 50's had a laminated beam roof planked with T&G Doug fir.
And there is a Catholic Church in the town near where I live that was built at the end of WWII that has laminated beam arches.
Edited 4/10/2008 2:36 am by Notchman
tanks to the education!
Ok,I'm gonna show off here,(my ignorance, that is) what is the difference between a gluelam, and an LVL?
LVL is thick plywood, and a gluelam is laminated the other direction?
A medium to large guy named Alan, not an ambiguous female....
NOT that there is anything wrong with that.
LVL is made like plywood, except instead of orienting the grain at 90Â° with each layer, all the layers have the grain in the same direction, pretty much like real wood except there aren't any weak spots.
Glulams are basically a stack of 2x6's glued together. Prettier than LVL's but more expensive.
Picture a pile of 2x6 glued together laid flat.
That is a gluelam. Most I have seen were built from 2x4 or 2x6 sizes, but anything can be done, depending on the spans and loads. As somebody mentioned, they are common in open architechtural forms like large asembly halls, curved arch supports etc
LVL is laminated veneer lumber. The orientation is vertical instead of flat, and the slices are 1/8" thinck instead of 1-1/2"
LVLs are typically 1-3/4" thick and you bolt/glue 2, 3, 4, or whatever together to obtain the total thickness the engineering dictates
Here's a couple more tidbits to broaden your horizons: A lot of laminated beams are made up of 1 1/2" thick stock, but many of the high load beams and many of the arches are made up of stock that is 1 3/8" thick. In the Weyco plant where I worked, the company would sell, at a bargain, units of stock who's moisture content had elevated beyond spec in storage. I bought quite a bit of that for building barns and sheds, but it was a bit narrower than normal construction stock and a bit tighter face for nailing up sheathing. It didn't have an eased edge, so, being Doug fir, it was a splinter hazard to handle, but it WAS really nice quality wood with absolutely no wany edges.
In the brief time I worked in that plant, they were gluing up the carabou crossing beams for the Alaskan pipeline. The beams I was helping lay up were 28" wide X 84" deep, by 160+ feet long. It took two large cranes with long spreader bars to load them on three railroad flatcars. Even then, they were as limber as wet noodles.
I also did some consulting for Trus-Joist in one of their first plants in Eugene, Oregon. All that plant made was the original LVLs which were ripped to width for use as the flanges on their "Trus Joists" we've all come to know and love (or debate over).
The LVL machine was just a continuous rolling hot press (to cure the glue) which was fed the glued up stack of veneers. To visualise this, consider that had the outfeed been unlimited, they could have made up one infinitely long 24" wide LVL.But of course, they cut those big, wide LVLs to length with a flying cut-off saw, where they were then transferred to a gang saw and ripped into the desired joist flanges.
Yeah - I bet some people don't realize that float glass is miles long before it gets cut to size too.
"Yeah - I bet some people don't realize that float glass is miles long before it gets cut to size too."
And steel studs too. A 20,000 lb coil of cold rolled steel runs through a slitter that cuts to width, then through a series of rollers that bend the stock into a "C" shaped profile, punches that knock out the holes that are spaced along the length and finally a cut-off shear - all at a rate of about 100 feet per minute, maybe more. 20 ga = about 2 1/2 miles per coil.
and OSB and DW sheets are huge before they're cut up into handy take home sizes....
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"handy take home sizes...."
Good turn of the phrase! I like that one.
My SIL's FIL just finished aligning the rollers at the USG plant in Portsmouth, NH. They extrude sheetrock in infinite lengths. If the rollers aren't perfectly level and straight, it's not good. They had been shutting the line down when the extrusion started running off. Now they can just keep cranking.
All this reminds me of the time I once asked how long I could get Steel roofing delivered. I was looking at a roof run of something like 58'
The answer was that I could have it a mile long if that was what I wanted, but that I had to provide the truck if it was any longer than 60' and that thermal expansion would give me fits if it was longer than 40'cuts.
Our church was built with laminated beams in the early 60s. I'd guess most exposed beam churches built from about 1955 onward used laminated beams. Laminating was the only way to efficiently produce the combo post-rafter piece that enabled construction of large spaces without rafter ties
So I have a question on this topic. What did any of you do to the hvac system in the houses where this work took place? It seems to me all of that would need to be tossed and replaced as well.
I think we're all trying to figure out what your question means. Wrong thread perhaps?
We hoisted more than I care to remember back in my apprentice years. Ultimately, there was always a "real man" with a beam on his shoulder climbing a ladder. We'd have redundant safties but realistically, it wasn't safe.
I was glad to see Microlams come around until I saw a 24" high one!
I also learned to hate the Stock lumber company who shipped out 11 7/8" LVLs on 2 x 12 jobs and 9 7/8" lvls on 2x10 jobs. We'd have to rip them down to fit. It took me years to learn that there were other lumber companies that stocked the correct sizes!
Bob's next test date: 12/10/07
Isn't cutting them down to size fun?
Got to love sawdust.