I'm a woodworking novice with the goal of putting together a simple convertible sofa / bed. My goals are to keep it simple and affordable to build. I'm planning to buy a couple sheets of plywood and have the lumber yard cut them and then hopefully put it together with just a drill. I made a design in SketchUp and am trying to use the Sagulator to understand what thickness/type of wood I need to use to make sure it has acceptable sag.
I am mostly looking for a gut check on whether I am using the Sagulator correctly, particularly the load inputs.
The sofa and bed will be used by two people 180 lbs and 120 lbs.
For sofa mode (2" thick) I used the following values and got acceptable sag:
180 lbs / foot center load - i assume a person sitting is maybe 1.5-2 feet wide, so 180lbs per foot should be plenty?
350 lbs / foot uniform load - seems more than enough?
For bed mode (1" thick) I used:
100 lbs / foot uniform load - again guessing based on how a person weight is distributed when laying down
Am I estimating the load correctly? Is there a rule-of-thumb lbs/ft to use for a sofa / bed, e.g. I guess when a furniture designer designs a piece for sale, there must be some typical standard load rating? I searched for this but couldn't find anything.
The design is very simple, two boxes each missing 2 faces. Stack them for sofa, set them side by side for bed. This means the thickness of the span in bed mode is 1" and in sofa mode it is 2" (2x 1"). I therefore assumed I can input 2" in the Sagulator, but not sure if that is the case?
I am still researching how to attach the "legs" to the "shelf". I was thinking to use pocket holes and some bolts of some kind. I'm most curious about the sag, but would also appreciate any advice on this.
Thanks in advance!
Picture of the "design":
Sagulator "sofa mode" - person sitting in center:
Sagulator "sofa mode" - people sitting distributed evenly:
Sagulator "bed mode":
83x32x10 inches is the bounding volume for each box.