Maybe a dumb question but where do I find span information for LVL’s?
I’m putting a new shed roof over a room attached to an old house. The horizontal roof span is 31′ and I will be breaking it up with an LVL header (2 nailed together) somewhere near the middle which will be bearing essentially 1/2 the roof load. The roof pitch will be close to a 4/12(governed by existing conditions), I will be using YP 2×8’s 16″ O.C. The top of the shed will be bearing on a ledger attched to the second story wall of the original house. The bottom will be bearing on a header on a new screened porch. The roof will be approx. 14’6″ wide(this is what the LVLs will need to freespan) and I would like to figure a 20lb. dead load and the ground snow load in my area is 15lbs/Sq.Ft.
How do I look this up and in which book? Is there a website that can do this kind of calculation?
Replies
The LVL suppliers each have a web site that lists the allowable loads and spans.
Go to the place that you will purchase the LVL.
Ask for an installation guide for the LVL's that are being sold.
There will be loading tables for beams, floors, roof ridges, headers, etc.
Most wholesalers/truss companies through your supplier will have a resource to calculate your specific loading conditions if you can supply a drawing/blueprint and pertinent details.
The header on the screened porch needs to be carefully calculated as it appears to be accepting a point load....provided I am reading your description correctly.
Point loads on a beam essentially double the actual loads effect on a beam. The calculations/formulae vary as per exact position of the load along the beam. This is where the supplier can effectively and accurately calculate and supply the correct LVL combination and describe how to effectively assemble same.
Turn it over to the professionals, and do your own calculations....then see how they compare. It will hone your skills....and probably humble your ego....even save you from a grave error.
.....................Iron Helix
IronHelix has it right - Go somewhere that sells 'em. They'll know local loading requirements, and how to calc the loads on the beam correctly.
Going to their website (as GHR suggested)is foolish unless you know how to do the load development.
I've got a program that calculates LVL, I-Joist etc....
You can get it at: http://www.bc.com/wood/ewp/index.jsp click-on software, they will send it for free.
I'll email the calculations
MRinger is right, their are a number of programs that can do the calculations, and reccomend a size, and grade of lvl.
Just had to do that today. Went to the yard, talked to my guy, he picked up the phone and called the manufacturer. Talked a few minutes about span, what the joists were above it, he already knows the loads for the area. He asked about adjacent walls and distances. Nice thing here is, if you do that, the codes department will take it, which saves you $200 for a rubber stamp from an engineer on simpler projects.
"If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man." - Mark Twain