single or double LVL ???

[xtal01]

OK, dumb question ...

I have a stairway to the second floor of my shop.

The floor is 16" TJI's (wood I)

The stairway is against the wall with the floor joists running parallel.

To frame the stairway, I am going to use an LVL rather than just another TJI. If for no other reason, it will be something solid to attache the railing on the upper floor to.

I did run on the Weyerhauser Forte software ... easily passes (obviously if a TJI passes than a LVL of the same depth will pass).

I only need a single LVL .. worst case only loaded to 40% of its' max

I was looking at a few houses in the area .. they all used a double LVL at the stairway opening .... they may have just needed because of the length and load or maybe there will be a wall above it or ?

As this is the edge of the floor do I need two? Is there anything I am missing?

Just wanted to make sure I am doing everything right.

Thanks ... Mike

 

[xtal01]

Just FYI .... I should try to use the correct terminology ...

The question should read Do I need a double trimmer on the side of my staircase?

I did a bunch more looking ... everyone seems to use a double but again maybe that is just because they need it for strength.

With a 16" LVL, the software says I will be fine ... but maybe I need a double for stiffness or ?????

Thanks again!

Mike

PS ... my wife put video #11 up today showing the build .... Link

 

[jayrod12]

The software says it's fine for gravity loads. But your guardrail/handrail will put some torsion into the beam. A wider beam gives you some more lateral stiffness. It also allows for longer lag screws for your guardrail/handrail. Most flimsy guards I've seen have inadequate fastening more than it being a member strength issue.

 

[xtal01]

Got it ...

Makes sense ... thinking back, I actually bridged between two joists in the house because I did not like how much flex there was in my railing.

It is only an attic area .. with some luck, no one will ever use the railing ... but I will definitely put one up around the stairway ....

I always try to think of safety first.

Thanks so much !

Mike