Expert: Daniel Humphrey - 3/23/2009

Question
I recently had a two car garage constructed and want to add a small loft storage area. The space will be 5' x 24' and I don't want any support columns in the middle. I would like to know what size micro lam (lvl) I need to support a 24' span. The area will be for storage only and it needs to support my weight (190lbs) when I climb up there to move stuff up and down. I was going to contsuct it with 2"x8" rafters, 16" on center, with a 2"x10"x24' plate on the wall and joist hangers for the rafters. I was going to go with a 1 3/4" x 11 7/8" micro lam for the span. What's your take? Should the lam be doubled up or bigger? Thanks

Answer
Dear Frank,

Your plan is sound. The only addition I would make is to add a full-length 2x4 ledger beneath the joists on the micro lam to take some of the bounce out of it.

Of course, the 24' micro lam might be a bit bouncy, and you will want all the heavy stuff near the wall. The good part of your plan is that if the front edge is too bouncy for you, you can double up that header. A hand railing built as a truss and tied into the header would completely solidify that front edge as well. Another way to stiffen it is to tie the header into the rafters above with vertical 2x4 strapping or even cables.

Carry on, and good luck.

Daniel