School me on my roof design

[diggler306]

My 24x24 detached has a cottage style hip roof. As you can see there is a triple 2x14 (i believe) LVL beam spanning the 24' width of the space. 2x6 joists 24" OC spanning just under 12' from wall to beam hangars.

I want to create a small cold attic storage area to hold the obvious seasonal decorations, and other random **** that you can see on my storage shelf in the photo. Maybe 4'x6' or 6'x6'. Once the ceiling is finished with 5/8" drywall, I'd like to know that I can get up there and over to the walls to fish new wires in the future without worry (170lbs).

Is this design good for anything other than keeping the walls up? What kind of load rating would it have?

 

[rsanter]

Looks very stout built, should be no problem as 200#s is not that much weight

Bob

 

[Dennis93]

You could just store that there on a piece of plywood. But the problem is the second you stir one thing you store more things. Pretty soon you have a thousand plus lbs up there without even knowing. Around here, code for less than 12 span is 2x10 16 o.c. That 2x6 is only there to effectively hold up any ceiling if you plan to put one up there as a 2x4 will deflect too much over that length.

 

[Dennis93]

Sorry just understood you want to get up there and you are 170 lbs. you can walk across those no problem, I thought you meant the stuff you store is going to be 170 lbs. I would just put some 2x10 up there and use tht for storage. Don't have to do the whole thing if you don't want to just the part you are going to store on.

 

[Pathfinder]

Diggler306,

I have been a registered Architect for 35 years and am very comfortable with structural design. Your triple 14" LVL over a 23.6' span will carry a total load of 6,227 lb. assuming you plan on adding a 1/2" gypsum board ceiling. The 2x6 joists at 24" o.c. spanning 11.5' will carry 16 pounds per square foot. Again assuming you plan on adding a 1/2" gypsum board ceiling. You probably will not store anything within 3' of the ends of the joists where the headroom goes to 0' so the total load carrying capacity of the 2x6 joists is around 6,000 pounds. To achieve the 16 pound per square foot capacity on the joists you will need to install a minimum of 5/8" thick plywood for the subfloor and it needs to be glued with construction adhesive and nailed at 6" on center. I would also recommend solid blocking between the joists at their mid span.

Please note that the above load carrying capacities are based on a stand alone garage with no other loads on the center beam other than the attic joists. If the center beam carries any loads other than the attic floor then the attic floor load capacity must be reduced

Hope this helps.

John Minton

 

[diggler306]

Thanks for the responses!

John, that's exactly what I wanted to hear, and very detailed - thank you! I'm planning to use 5/8" drywall on the ceiling and 1/2" on the walls. Will I get 16 pounds per square foot over the 6'x6' area if that's all I cover? I only want a small space w/flooring because I will only be able to get R22 in that area, and I'm hoping to go R35 everywhere else.

 

[ddawg16]

Pathfinder....NICE response.....it's a fresh change to see 'accurate' responses.