LVL Layup

[UnneutralAxis]

I should probably know this, but I don’t.


I have some tall walls on a job that I spec’d some 5 ½” deep LVLs on as studs. The contractor wants to rip down some 11 7/8” LVLs. I know if it were a glulam it wouldn’t work because of the higher grade lams as you move from the N.A., but I was thinking that maybe LVLs don’t have a particular “layup.” Does anyone here know?

Thanks.

 

[msquared48]

In that LVL's are vertically laminated as opposed to the horizontal laminations of Glu-Lams, I don't think there would be a problem of the type you are imagining.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[UnneutralAxis]

Great point. Should have stopped to think a minute more. I was thinking they are glued up like a glulam, but they are not.

 

[Ron]

Uh...hold the phone there a minute. If you modify, the manufacturer might cry foul and not stand behind in the event of a failure. Further, bending properties are probably empirical and wouldn't necessarily have linear relationship to uncut section.

At the least, get the manufacturer to approve, in writing, the use and modification.

 

[msquared48]

Good point Ron. I'll have to second that.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[UnneutralAxis]

Yes, great point. I appreciate the insight.

 

[apsix]

Getting manufacturer's approval is always a good idea, but LVL sections are typically made by ripping down from 1200 or so wide slabs, so ripping your own shouldn't affect the properties.

 

[a2mfk]

Instead of all that work of ripping larger LVLs, why not try traditional 2x6s at decreased spacing until your wall works? At some point deflection will control anyway with a tall wood framed wall and LVLs won't help that much in terms of E.

 

[UnneutralAxis]

You'd have to see the situation. The LVLs are doubled @ 12" o.c. and are 18' long... too long for 2x6s. Of course, deflection is the issue here. It's a long story how we got to a wood framed wall this tall, but it involved an architect and that's all I'll say.

I don't see why the contractor didn't just buy the LVL wall studs like I said in the plans. They're already the right depth.

Anyway, issue is over now. Wall in place.

 

[a2mfk]

Funny, I was even going to say something like, "Even if you have to go to 6" o.c. with 2x6s", but you are already there. I have had to do a few unique tall timber framed walls (two story open rooms) and go with larger members or decreased spacing. Usually this type of wall is better to do with exposed post and beam and nice steel connections like you would see in high end cabins, ski lodges, etc. If the architect wants lots of glass, using HSS is not a bad approach. Working with several steel fabs I have convinced residential contractors and GCs we can use steel, its not that difficult or expensive and in some cases may be cheaper.

Anyway, your problem is solved, feel your pain...

 

[Lion06]

Engineered lumber manufacturers typically frown upon modifying their members. I looked into this recently and the manufacturer I talked to said that they actually rip the board to proper depth, but after they are ripped is when they do their quality control. Because of this, they recommend against ripping it again.

Even armed with that information, we decided to go ahead and rip 1/2" off the end and require the ripped side to be placed up so it's in compression. You don't really have the ability to ensure the ripped end will be in compression, so I'd be careful.