Garage loft


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Old 10-23-13, 12:05 PM
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Garage loft

Hi, Could anyone please advise on a 4' x 11'6" storage loft above my garage door. I basically plan to add a 2x6 or 2x8 ledger on the three walls (garage door wall and two side walls) and I am undecided on whether to install a double 2x6 or 2x8 beam with a perpendicular support joist or to just do 2x6 joist across the 11' span. Below is my best representation of what I am thinking are my two options. In the bottom picture, one side of the picture is a 2x6 24" on center and the other side is 18" on center. Is either more desirable or necessary? Any other advise?

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Old 10-25-13, 10:41 AM
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Welcome to the forums!

Here are standard loads for Doug./Fir 1500#fb; 4' 1-2x6= 473#sq.ft. 12' 1-2x6= 52# 4' 1-2x8= 821 12' 1-2x8= 91#
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12' 2-2x6= 87 12' 2-2x8= 152

So in first dia. - 52# per square foot x 12' = 624# x 4' = 2496# total. Second dia. the 4' 2x6 running to the double 12' is the weak link. Figure; the farther the on-center spacing- the weaker the loads. 12"oc is load per foot, 16"oc is load divided by 1.33 (16"/12"); at 24"oc is load divided by 2 (24"/12"). Figure 1/2 the area (1/2 the 4' span x 1/2 the 12' joist span = load (2' x 6' = 12' area x load per square foot (of o.c. spacing figure).

Gary
PS. are you storing engine parts or seasonal items?
 
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Old 10-31-13, 04:30 PM
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Overbuild once

In my opinion if you have the room for a 2x8 floor use 2x8. Pinching pennies when building structures for any purpose is wrong. For floors I would use nothing less than a 2x8 carry the load directly to foundation where possible and use joist hangers from beams where this is not possible. In a house nobody these days would use 2x6 for a floor that you are going to walk on or below, why do it in the garage?

If you have a picture of the garage and the intended area it would provide adequate knowledge to give you a little help creating a structurally sound space and some peace of mind.
 
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Old 11-05-13, 08:29 AM
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I've built a number of garage lofts, and every single one had the joists running in the short direction--as is done in most house framing. Spanning in the long direction doesn't make sense, as it causes higher stresses in the joists, resulting in less load-carrying ability. I've never considered using 2 x 8s for joists or beam members, as they would take away 2" of storage volume (and head-room the few times you need to crawl around up there).

I've always used 2 x 4 ledgers along the walls, 2 x 6 joists held by joist hangers in front and either resting on the ledger in the back or using a flush ledger with joist hangers there, too. The front usually gets a built-up beam (long direction) composed of 2 x 6s, flanged or supported at its midpoint with a hanger from the attic framing.
 

Last edited by BridgeMan45; 11-05-13 at 10:52 AM.
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Old 11-06-13, 07:44 AM
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Most garage roofs aren't built under the impression that they will supporting a storage structure later on. 2" of storage? In my opinion 2" won't make or break the amount of rubber maid storage containers you can stack or how many times you hit your head on a roofing nail crawling around up there. If you can support a 2 ply 2x8 beam and both sides of garage and fill in the middle with 2x8 joists (or if you want to save $10 2x6 joists) there's no need to add a support from the roof (that will likely sag in time). Create an independent structure that doesn't effect the current building.

As always opinion only (if 2" makes or breaks your storage capacity and you want to save $30 in lumber read below).
 
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Old 11-06-13, 09:00 AM
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And if one is bound and determined to waste materials and overbuild capacity, why not replace all of the flimsy 2 x 8s with at least 2 x 12s?
 
 

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