Has anyone thought or made their own TGI joists. Got to talking about it during a break this past week. Quick thoughts on it where something like dadoeing (sp?) something like a 2×4 on the flat with OSB as the webbing.
Just pondering the idea.
Thanxs,
M2akita
Replies
Funny, I've had my eyes glaze over at break too while staring at a pile of TGI's!!! Thought "hey it's just a 2x3 with a dado, some glue, and osb...right?" Don't think I'd ever actually consider doing it though. Even if I felt up to the task I couldn't make anything longer than 16" without ripping larger stock or trying to finger joint a 2x3....besides the inspector would probably have a heart attack and I'd be looking at a manslaughter beef!
Don't see that I think it's at all practical.
Putting grooves in the 2X chord material might not be any big trick. And tapering the edges of some plywood might also be possible.
But how are you gonna splice the chord material? Or the webs material? What kind of glue do you need? How much claming pressure? Can you mill the mating surfaces perfectly, so you get a consistent depth?
Do you really want a homemade floor system? Can you imagine the expense and effort it would take to fix them, if they didn't end up holding together?
If only the good die young then what does that say about senior citizens?
Boss Hog,
I agree, I dont think it would be practical at all. From a structural/ technical side I would be very leery. It was more one of these 'hmmm, I wonder' type discussions. Thought Id see if anyone has actually tried it.
M2akita.
Ok, then how about homemade trusses?
(G, D, & R)If everything seems to be going well, you've obviously overlooked something.
"Ok, then how about homemade trusses?"
Ya just Ccouldn't resist, could ya ???If you were going to shoot a mime, would you use a silencer?
Code violation 1:
When you cut the groove in the stock, it needs to be regraded.
Code violation 2:
The APA gives the allowable design strength for plywood and osb construction details. Your butt joint does not meet code.
Code violation 3:
The concept is outside of the perscriptive code. It needs an engineer's stamp.
Typical I-joists cost about $1.50/ft. Not a lot more than #2 2x4s.
Once again I think some folks are using this as an opportunity to spout off all of their "knowledge" and cut down others' speculating.
As someone who answered the poster's original question..."anyone ever think of making your own..." I would have to say that this wasn't seriously being considered at a real world solution. I believe the thread was just kind of a thinking outloud type of thread. Sorry to disappoint those of you who were peeing your pants in anticipation at the opportunity to comdemn someone for such foolish notions.
I do believe, and certainly hope that readers and posters alike can discern the difference between a thread such as this and one where someone was looking for an expert opinion on how to build something.
Thank you dieselpig! You interpreted my post as I had meant it. I hoped that the thread wouldnt go too far in the warning end. Better safe than sorry though. I also wondered how long it would take before we got onto trusses ( really thought it might go that route since Boss Hog was one of the earliest posters).
Thanks for all the posts though everyone.........Here's to the 'Red Green' in all of us.
M2akita
Oh, so your question was: Can you do it?
Sure. Put a factory. Make your joists. Relocate the factory.
Duct tape is better/easier than glue any day
was waiting for you to chime in on this one :-)View ImageGo Jayhawks
I had an attic retro. Ceiling joist were 2x6....not enough for ppl. Manufactured TGI were too tall for the envelope. We took 2x6x16, dadoed & put 2 strips of 3/4 OSB in w/ finish nails & OSI const. adhesive. Did a "deflection test" w/ 500 lbs of men... was equivalent to a single 2x8x16...3/4". No idea how it will last over the long haul, but I would have put them in my own attic. Dont think would use on a regular house floor tho. Loads will be less in the attic bedroom.
I also feel that manufactured TGI is a better buy for a LOT of reasons. Liability not the least.
'Round here that's called a "brain fart". We all do it, some more'n others. Rod
I had the privelege of touring the Trus Joist plant near Valdosta Georgia- Thing that impreesed me most was the quality control over ALL the processes- veneers, glues, stress ratings, inspections etc. to achieve consistent, predictable product. Home made are not in the same category (no offence intended)
(keep in mind I love the idea of the unconventional and DIY solutions, but...)
Trying to replicate conventional TGI strikes me as insane, for all the risk reasons, but mostly because you couldn't really save any money either. Around here TGI's up to 11 7/8" run almost the same price as 2x material and no way could you save anything slapping together parts.
In certain situations, however, attaching the web to both sides of the cords (a-la box beam) can be a reasonable $-saving project for high strength beams not too long.
If I recall, the web is compressed before being glued into the dado, too. I imagine they have a good reason for doing that.
Hope you understand that many of the posters here may appear overly careful because they know that building projects gone awry can be dangerous and they don't know who will read their posts and do something, well, you know........
I'm sure it was someone, thinking about what you are thinking, who went forward with it and that's why we have TGIs!
Really baaadddd idea...... Damn, now I'll have to try it sometime. {G}
It doesn't matter how fast you get there, it just matters that you go in the right direction.
I'm in favor of any attempt at the use of ingenuity. 9 times out of 10 a person with a little common sense and the smarts to "overbuild" when in doubt will have good results. I'm just not in favor of sticking your neck out when it makes no finacial sense.
2-24' 2x4 = $15
1- 1/2" OSB = $7
adhesive, etc = $4
Total: $26 plus at least an hour of your time, minus the effect of knots & checks in the 2x4, minus the seams in the OSB.
24'x 11 7/8" TGI @ $1.19/ft = $29 + the honor of having a multi-million dollar company to sue if you have to. Can't beat that.
Mr. G,
You proved the point $29 - $26 = $3. You save $3. [Or as the generals say: "One saves $3."] In any event, I would suggest using plywood instead of OSB because it looks better. The adhesive should be Rescorcinal Glue. And also use plenty of drywall screws to hold it together.
~Peter
Lizards are not Iraqi. Moths maybe are.
You may want to rethink your dw screw recommendation before Piffin comes around.
Has everybody forgotten the time factor in making your own stuff?
Jon Blakemore
He mentioned the screws just for me. I knew he's having fun with April's Fooling. Just like this whole thread is an April Fools day joke.
.
Excellence is its own reward!
Just a few piddling comments.
I know there are multiple manufacturers now and the name we give to them is generic. As I understand it, they are referred to as 'TJI's because the first company that produced them for market was Macmillan-Bloedel's TRUS JOIST INTERNATIONAL. What does TGI stand for?
The TJI's that I've worked with have always had flanges (chords) comprised of LVL (laminated veneer lumber). Do I understand correctly that some TJI's are produced using finger-jointed solid wood flanges?
Don't you guys think the Big Boxes should try to sell more TJI's to DIY's ? :o)
Ken Hill
Lot of questions there Ken. don't exceed your daily quotient.
;)
TGI is a mistake a lot of people make it stands for nothing but we could gice it a designation like "Those Good I-Lams"
Yes, somne generic ones are now made with lumber instead of laminated chords.
I don't think that the box stores should sell engineered product. That said, I know that my supplier fanatically makes sure to provide me a sheet with proper installations shown with every order, even tho he knows that I know...
I wonder if the boxes do the same to cover the liability issues..
Excellence is its own reward!
I wouldn't build ply truss joists for anything of much value. I was thinking it'd just be kinds fun to mess around with.It doesn't matter how fast you get there, it just matters that you go in the right direction.
>>> ... with a little common sense and the smarts to "overbuild" when in doubt ...
I think that's they key. If I were in a situation where I needed a long span and couldn't get i-joists and could get dimension lumber and plywood, I wouldn't hesitate to build my own. I'd select clear material for the chords, vertical grain if I could get it, and splice them with long scarf joints, probably with an interlocking glue joint to increase surface area. I'd use AC or better plywood for the webs, and splice them with long lap splices, 15 or 20 times the thickness of the plywood. Instead of worrying about the clamping pressures for some high tech glue, I'd use epoxy. I'd design for higher than normal dead and live loads, and aim for a maximum deflection of L/1000. Before I finalized the design, I'd build a couple joists, put some blocking between them, and a subfloor on them and test them to destruction. Etc, etc.
But I wouldn't be doing it to save money
I understand. Still...
"If I were in a situation where I needed a long span and couldn't get i-joists and could get dimension lumber and plywood"
...It's hard for me to imagine how one would get into that situation.
But I like your gumption!
>> It's hard for me to imagine how one would get into that situation.
Me too. That's one of the things that allows me to pronounce so boldly. :)