What can I use as an alternative to 3.5 by 9.5 LVL support beam?

tjones10 · 08-20-2008, 08:31 PM

I recent had a structural engineer provide me with the specifications for a load bearing beam. He stated 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 require 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.

**Termite** · 08-20-2008, 09:08 PM

LVL's do in fact come in 3-1/2" width, just not in all markets.

In sizing structural lumber materials, adding depth typically reduces the necessary width. But, it is impossible for us to determine if you can get away with three 11-7/8" LVL's instead of four 9-1/2".

You say you're worried about the depth. Why is that? If I had to guess, I'd say that you're concerned about the beam's ability to take the load without perceivable deflection. A deeper beam is stronger, but if it is narrower you're cutting its ability to take the load. Therefore, you might get similar deflection out of a three ply 11-7/8" beam. It might even be a bit weaker.

Your best bet is to find a local lumberyard that stocks and sells LVL (not a box store). A good yard with engineered wood products will also have the capability to size engineered wood beams for you. If you're buying your beams from them, they'll do it for free for sure. Have them compare the deflections on the spec'd beam and the narrower/deeper beam.

If you're still concerned, do a four ply 11-7/8" LVL and remove all doubt.

Remember that four or more plies must be bolted together.

Joe Carola · 08-24-2008, 11:30 AM

Quote:

Originally Posted by tjones10

I recent had a structural engineer provide me with the specifications for a load bearing beam. He stated 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",

LVL's come in 3.5" and any lumberyard can get them.

Quote:

I would like to know if there is an equivalent LVL specification I could use to reduce the number of LVLs require 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

You can always reduce the amount of lvl's spec'd by increasing the height if you have the room. It has to be spec'd by the Architect or Engineer who drew them.

If it was spec's with 2-3.5" lvl's, you better call the Architect or Engineer who drew them and ask them if you can use (4)1-3/4" lvl's because depending on what your holding up, it's not the same thing.