Attic storage flooring

BrandonD

Hi guys,

Moved in to our first house back in April. We have an attic accessible by a pull down ladder. When we moved in we just piled all of our attic storage items in the garage to go through before finding a permanent spot for them. I'd really like to reclaim the garage if possible and store items up in the attic. The previous owner had a few sheets of plywood nailed down for some flooring around the ladder opening. I'd like to rip this out and put in a plywood floor above the garage but want to ensure the joists, trusses, whatever I have can support the weight. It will never be used as a living space and will hold holiday decorations, old "memories", etc... basically a bunch of bins with no single bin exceeding approx 100-125 pounds.

What kind of information and pics do you need from me in order to determine if the structure can support this load, type of plywood or other flooring I should use, etc.?

Thanks,
Brandon

tony.g

Ideally you need to show pics as you seem unsure of the difference between trusses and joists.
If it's a truss roof, then you need to be very careful about loading as most trusses are only designed for ceiling boards, insulation etc.
If it's a traditional cut roof with rafters and joists, they are a little more forgiving of loads.
Having said that, several bins of 100lbs+ represent a few concentrated point loads - not ideal on any ceiling.

BrandonD

Thanks Tony. I believe I know the difference between trusses and joists but as with the electrical subpanel I took on with the help of this forum I want to be sure of what I'm doing. I've read where a lot of attics are not designed for storage loads let alone living spaces so I want to be sure. It's already going to be inconvenient to move bins around up there because of the trusses so I might just pull the plug on it if there's too much concern.

100lb bins are worst case... I imagine only a couple bins would be greater than 100lbs, the ones with tons of extension cords for the exterior Christmas decorations come to mind. Most will be under 40 pounds.

Any particular view I'd need to get in the pictures? It's easy to get up and down from there so if I need to get a closer picture of something it'd be easy. I'll try to snag some wide angle ones when I get home from work.

Bondo

Ayuh,... Why not just use what's already there,..??

BrandonD

Some aren't nailed down and they've been placed haphazardly. Additionally I'd like to confirm it's safe to store up there and not just assume a previous DIYer put some stuff down and called it good.


Wide view -- west side


Wide view -- middle (1 of 2)


Wide view -- middle (2 of 2)


Wide view -- east side


West side resting on exterior block


East side resting on exterior block

TheCamper

Trusses are an engineered product and your trusses were likely designed to support drywall on the bottom chord. You will want to consult with the truss manufacturer or an engineer before loading the trusses with storage. If you do nail down plywood throughout the attic area use a nail gun as opposed to hand nailing. All that hammering near the connector plates can shake some loose, nail guns tend to cause less disturbance. Also, if the last owner cut a hole in the garage ceiling and put up the pull-down stair make sure he kept a fire separation between the garage and the living space. A pull down stair makes the space above the garage the same hazard as the garage. The typical required fire separation then would be between the garage attic and the living space. good luck with the new house.

BrandonD

Thanks for the insight. Any idea on how I can determine the truss manufacturer? I'm guessing they might stamp them?

Daniel Holzman

Unfortunately many truss manufacturers do not mark their name on the trusses. The lumber grade should be stamped on the 2x4's, but not always the manufacturer name. Alpine http://www.alpeng.com/ is a large designer and manufacturer of trusses, it may be possible for them to analyze the loading capacity of your truss if you contact them. This service is not likely to be free, however it is likely to be less costly than hiring a structural engineer to evaluate your truss support capacity.

BrandonD

I had an email conversation with Alpine per your suggestion. They said they had internal structural engineers who might be able to help me. Unfortunately they reported back to me that they would not be able to help me as they ruled themselves out as the manufacturer by the plates used.

I guess my options are to hire a local structure engineer to calculate the PSF or find some other place to store my crap?

Gary in WA

You are in Zone 2: http://publicecodes.cyberregs.com/ic..._11_par002.htm

R-30 is required (minimum) in your attic; http://publicecodes.cyberregs.com/ic..._11_sec002.htm
That would be higher than the bottom cords of the trusses. Either use it as storage and waste heat/cooling dollars or elevate the storage above the minimum insulation height, R-value to save money. You should air-seal the attic first; http://www.google.com/url?sa=t&sourc...wWATQw&cad=rja

Gary

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BrandonD

Hi Gary. Thanks for your feedback on the insulation. As you can see, there is no insulation above the attached garage. The rest of the attic is a combination of blown in insulation and rolls as shown in the below pictures. How do I know if the insulation is sufficient where it's at? Would I be better off starting a new topic in the insulation forum? Thanks.

Gary in WA

Start one in "Insulation", can't go wrong...

Gary

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