2x? Load Capacity

MarchieB

I asked this question in the DIY forum and got a few responces but no real answers.
I want to build a shelf above my garage door for storing seldom used items (seasonal tires on rims, christmas deco/lights and various junk in garage)
I have attached a "rough" picture of what i have planned. The shelf is approx 16ft. wide by 3ft. deep. I cannot (don't really want) to add a support up to the rafters in the ceiling from the centre of the front section as the garage is fully drywalled and painted.

The question i have is in regards to the front load bearing beam (marked with the ???) what size of lumber 2x? should i use to span the 16ft?

I originally wanted to use 2 2x6's laminated and bolted together but am not sure if it would be strong enough.One of the reasons for 2x6 was to have as much room as possible between the shelf surface and the ceiling.

Would using 3 2x6's be enough? Or 2 2x8's ????

I don't really have any experience (and can't really find a straight forward answer online) on calculating the load strength of the lumber.

Any help would be greatly appreciated.

Thanks Marcello

Attached Thumbnails

 

dougchips

I wish I had an answer. I tend to use LVL's instead on 2x's for loads, for longer beams I use 2 lvl's and a steel plate bolted together. Finding straight 2x stock should be fun.

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RobertCDF

3 or 4 2x6's might do it... But I am not about to say for sure. I would feel confident with 3 2x8's spanning 16'. But again not something I could guarantee.

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send_it_all

What you have drawn is MORE than enough to hold the weight you describe. you could easily get away with a 2x4 frame (similar to the one you drew) screwed to the wall studs with 3/4" plywood screwed down on top, another 2x4 screwed to studs 2 feet below the frame, and 2x4s angled down from the upper frame to the lower ledger all screwed together. I dont have any official load calculations for you, but 2x4s or at most 2x6s would be plenty strong.


and by the way...the cross bracing on 12" centers is ridiculously overkill...4' on center would hold that engine block, but the screws in the wall studs wouldnt.



one more thing...............72 monte carlos kick a$$

Same Old

I think he wants this over the door so angled barckets won't work.

I'd double a 2x6. But it will be pretty bouncy in the middle. Hanging the center with a couple threaded rods is an easy way to get a stronger shelf. If you have access to the attic you can simply tack a 2x4 on top of the truss bottom chord and drill a hole through the drywall and the 2x4 and add a washer/nut. Run this down through the 2x6s on the front of your shelf.
No need for any bolts anywhere either. You're not putting much wieght on this. I would be comfortable screwing the back and sides to the wall studs. Make sure you get at least 1 1/2" into the stud. 1/2" CDX would be fine for the surface. 2x4 2-4' on center would be adequate for the intermediate supports.

RussellF

With that long a span and only supports on the ends I would use no less than 2x10s(2 or 3) laminated together, you can use smaller lumber to make up the flooring of that shelf. I would say that seasonal rims with tires on would be pretty heavy in addition to other things you may put up there.

Same Old

A single 2x10 calcs out as an allowable ceiling joist at L/180 16' span #2 Hem-Fir north with a 20 psf live load. Your tires and rims won't exceed that.

Or, you could go with some dudes gut instinct.

Scott Young

Mixed southern pine

2x8 select structural

floor joist L/180

12 inch spacing

live 30 psf
dead 20 psf

18 ft. 9 in. Span maximum

if you attach one to the wall, place one on twelve from the wall, and then the edge within the next twelve, you will be all right.

i would attach side bands and use joist hangers to fasten the joists.