SISTERING JOISTs or LVLs
SISTERING JOISTs or LVLs
(OP)
I am helping a friend who is wanting to add a room in his attic. The current joists are 2x8x16 - 16" OC.
He is wanting to add a set of stairs from the second floor to the attic. The stairs are to code but i told him that his fastening points look questionable.
The room underneath is a bedroom with no supporting stanchions. The room dimensions are 15x15, with 8 foot ceilings. He cannot put 2x10s in due to height restrictions.
The questions is should he use 3.5 x 7.25 LSL in the framing for the stairs and floor support, per attached schematic, or what is the best recommended proceedure to make sure the ceiling will support the weight of a bedroom?
Attached is a homemade schematic. (Dont laugh
)
Thanks in advance.
- Mike
He is wanting to add a set of stairs from the second floor to the attic. The stairs are to code but i told him that his fastening points look questionable.
The room underneath is a bedroom with no supporting stanchions. The room dimensions are 15x15, with 8 foot ceilings. He cannot put 2x10s in due to height restrictions.
The questions is should he use 3.5 x 7.25 LSL in the framing for the stairs and floor support, per attached schematic, or what is the best recommended proceedure to make sure the ceiling will support the weight of a bedroom?
Attached is a homemade schematic. (Dont laugh
Thanks in advance.
- Mike






RE: SISTERING JOISTs or LVLs
Answer: Hire a licensed professional structural engineer to review the proposed modifications to the existing structure.
RE: SISTERING JOISTs or LVLs
Have you checked deflection for the sistered joists? how do you plan to get them into the attic and into place?
Check the point loads too on the load bearing walls.
RE: SISTERING JOISTs or LVLs
RE: SISTERING JOISTs or LVLs
From the sketch I am wondering about headroom at the top of the stairs. Do you have a rough sketch of section through the attic?
Joseph
RE: SISTERING JOISTs or LVLs
RE: SISTERING JOISTs or LVLs
sundale & ztengguy have it right.
LVL's have advantages over sawn lumber. Higher E & Fb. Straighter than sawn. Sawn lumber will shrink substantially as it dries to equilibrium MC, LVL nowhere near as much.
As far as size & number, see first sentence.
Ralph
Structures Consulting
Northeast USA
RE: SISTERING JOISTs or LVLs