Replace a load bearing beam with LVLs?

Question

I recently had a structural engineer provide me with the specifications for a load bearing beam. He stated that I require 2 - 3.5 x 9.5 LVLs 1.7E supported by 6 x 6 timber posts.

Since LVLs do not come in 3.5", this ends up being 4 LVLs at 7 inches (1.75" each) in total. I am not really worried about the depth of the LVLs. I would like to know if there is an equivalent LVL specification I could use to reduce the number of LVLs required from 4 to 2 (maximum 3).

For example, is it possible to use 2 or 3 LVLs at 1.75" by 12". Please let me know.

Answer 1

LVLs come in 3.5. See this website. Georgia Pacific.

http://www.gp.com/build/product.aspx?pid...

Answer 2

3.5" LVLs are available, but only in very limited market areas.  

This is not a problem, you are correct that 2 - 1 3/4" LVLs are equivalent to 1 3 1/2" LVL, with the exception of fastening method.  4 plies must be bolted, with 2 you may be able to use long nails.

There really is not enough information here to determine what alternatives you may have.  There are many factors that must be considered in selecting a beam for a particular load condition.  

Having said that, there should be alternatives available using a deeper LVL.  Using fewer plies of a deeper material is generally less expensive, so that would be an added bonus.

One exception to the rule is if a wider beam is required to spread a load bearing over a greater area on a support.  Since you are using 6x6 posts, you should have room to go down to 3 plies of something since the top of the post is only 5 1/2" anyway.  

Your engineer is the proper one to answer this.  Again there are many factors in selecting the proper LVL.  These factors are generally analyzed with special computer software that accepts the span lengths, loading conditions, and other variables and produces a list of suitable solutions.  Since your engineer has already identified all of the input information, it should literally be a matter of selecting a different solution from the list of suitable options.  There may be a charge involved, but it should be minimal.  Very minimal.

Answer 3

I suggest you click on  Science & Mathematics in the category list, then click on Engineering and ask your question there. These guys and gals are pretty darn smart.

Answer 4

We have often use 1/2 inch steel sandwiched between two LVLs. What is the reason you don't want 7" of beam? Will it be visible? Most beams that are visible are usually trimmed with 1x8 anyways. A tall and skinny beam may look awkward. Will it be under floor joist or in line with them?

I've been a carpenter for 19 years and have never seen a 3.5 LVL. They do have 12"x 1 3/4 though. Not much more I can say without knowing the load and the span. I'm not sure how scientific this  is but 7x9.5=66.5

5.25x12=63. Pretty close to the same amount of material so probably the same strength as well?