Hypothetical Lumber rack question. How much weight??

[Matthew Curtis]

How much weight can a lumber rack hold that has 12" brackets secured to 2x4 wall studs that is 10' heigh? Lets say that the bracket is not the weak point. In other words how much weigh can a 2x4 stud handle? How much weight can be hung off of a 2x4 studded wall that is 10' heigh and the weight evenly distributed over 10' long?

[Charles Wiggins]

An engineer might be able to give you a more informed answer, but it seems to me that there are a lot factors to consider to get close to an estimate, for example:
1) What kind of wood? Fir? SYP? Straight grain? Knotty? I've seen studs that were cracked so bad that they would be guaranteed to fail. New fir is very soft while well aged SYP where the resins have set up is almost as hard as green oak.
2) Are the studs toe-nailed? Or nailed through the top and bottom plates? What size nails?
3) Is the wall sheathed on the back side?
4) Can you use both sides of the stud wall so the weight is distributed more evenly on both sides to cancel out the lateral forces that would tend to pull the studs away from the top plate?
All of these things, and several others will play a role in how the wall would perform. How to figure all that out into a figure like x lbs., I have no idea.

I know this is probably not very helpful. Maybe others will be able to share some definitive experiences.

[Mike Cutler]

Alot!

My "Lumber Rack" is homemade shelf brackets, secured to 2x4 studs with 4" screws. There is a lot of wood on that rack, and it's all heavy dense tropical hardwoods.

You would need an engineer to do a "moment calc", but the limiting factor will probably be the length, diameter and material type, of the lag screws holding the shelf brackets to the studs.

[David Nelson1]

I did a variation of the wall mounted rack. I used 4X4 pressure treated for the studs and double secure it to the concrete with 2X6 blocks that where secure to the block wall the nailed from the sides to help prevent bowing from the wall. Over kill probably but it was too easy not to do when i was studding the shop out.
Link to thread discussion: http://www.sawmillcreek.org/showthread.php?142654-Wood-Rack-Concept

Link to pictures before populating the rack. http://www.sawmillcreek.org/showthread.php?145774-Finaly-making-some-progress-in-the-shop.

[Bob Winkler]

I can't answer for sure, but the steel brackets that I'm looking at (the ones with the diagonal brace) claim to be able to support 1000 lbs per pair when lag screwed into the studs of a 2x4 wall. So my plan is to mount 4 across per level and load it with wood. When I built the shop, I put 1/2" plywood under the drywall on this particular wall for extra strength.

My problem is that I don't have a feeling for what a 12" high stack of lumber really weighs.

Bob

[George Bregar]

I've wondered this myself. I had my bother in law fab me up a lumber rack...18" brackets 12" apart so 7 total on my 8' walls. WOnder about the weight...and of course that weight will be 18" off the wall. I'm hoping someone in the know can provide an answer in generally usefull terms, and not some numerical value that I don't really have the means to practically measure.

[paul cottingham]

I just built one that is essentially a freestanding wall. it is anchored bottom and top, and uses 14 in shelf brackets. I have it loaded up, with no problems at all.

YMMV

[David Nelson1]

here is link for a good guesstimate

http://www.callkits.com/Lumber%20Weight.htm

[Matthew Curtis]

So approx. how much weight does everone have hanging directly to there studded wall? Is a 800lbs too much for an 8' section? 1000lbs, 1500lbs?

[Brian Schroeder]

I handle mostly aero structures, i.e. commercial aircraft wings which are primarily aluminum. So am not sure what construction engineers use for wood allowables. Seems to me like they would vary a lot. Just quickly looking I found a minimum allowable of 625psi for some 2x4s. Assuming 3 shelves (24" deep) all equally space on the 10' stud, I came up with a shelf weight of about 175lbs. This really depends on how far away from the wall you put your lumber. I didn't include the weight on the roof, so that value could be worse. But in general the farther away from the wall you put your wood, the less weight you should apply. Think of it in terms of you trying to lift a vacuum with your arms fully extended, it's a lot harder to lift than if the vacuum was right next to your body. If you can apply the same loading to the opposite side of the stud, than things get better like Charles said. It's like carrying two 5 galleon buckets in each hand rather than carrying one 5 galleon bucket. It balances out the loading (moment) on your body.

I think the biggest thing I would be concerned about applying lots of loading to shelves on wall is whether your wall will creep and bow in. Apply a relatively small constant load to a piece of wood and eventually it will start to creep. Thus your wall will start to bow in.

[Bruce King]

I hope everyone that reads this will understand and do what I recommend.

The wall studs have a weak link when used for wood racks, this is where the top is nailed to the top plate.
It does not matter if its toenailed or nailed through to the endgrain, it is scary to rely on this for wood racks.
You don't know for sure how many wall sheathing nails or staples are present so you can't add this in.

You need either metal angle or wood nailed across the ceiling joists to act as a block to prevent the wall studs from rotating inwards.
I recommend at least 4 ceiling joists for small to average racks and more for heavily loaded ones.

Don't use screws, you need the shear strength of several 16d nails for this.

Don't say "well, its been there for x amount of years" either. it does not matter one bit.
Structural failures often occur all at once and most likely while you are standing there adding a piece of wood to the stack.

I have 4x4 posts bolted to studs along with the top bracing to transfer the forces to the ceiling joists. The 4x4 posts are drilled out at slight angles to hold black iron pipes to provide the "shelves".

[Brian Schroeder]

From the above example I gave the shear load at the top and bottom of the 10' stud is about 53lbs. If it was a 8' stud they would be around 66lbs. From what I can tell a normal 16d framing nail can vary anywhere from 96 - 187lbs. Given most studs are fastened with two 16d's the total capability is about 192lbs. Say they aren't put in well so only take 50% of the capability, that still leaves you with 96lbs of capability, well above the loading seen at the joint. Not to say clamping the ends of your studs as Bruce suggested is bad, but I would probably be doing that more as a prevention on creep than as a prevention of failure. Attaching vertical legs going form the floor to each of the shelves (instead of the shelves cantilevered off the studs they are now supported on both sides) is an extremely good way of increasing the capability of the shelves, as the stud won't have as high of a moment applied to them.

[Jim Falsetti]

I also made a free standing wall a few months ago. The vertical 2x4s are secured with Simpson ties at the top plate and garage floor. the shelves are 11" deep with half lab joints, all made from 2x4s. Each vertical member is 30" on center. There is a 6 inch space between the back of the lumber rack and the wall of the garage where tall flat stuff is stored.

[Tim Sproul]

So approx. how much weight does everone have hanging directly to there studded wall? Is a 800lbs too much for an 8' section? 1000lbs, 1500lbs?

I haven't put my lumber on a scale but my guess is 2000+ pounds. This is on 10' high 2x4 wall. I use an adjustable metal rack similar to what Lee Valley sells. My rack is canted so the tips of the arms are a bit higher than where they attach to the wall, helping to reduce forces pulling the wall into the room.

[Lee Schierer]

You also have to know what the top plate looks like. Is it a single or double 2 x 4 top plate? Is this a double stud or single wall stud? Is this a load bearing wall where some load has already been placed upon it from a roof or building above? The father from the wall your support extends will add more loading to the nails at the top of the stud and the top plate. Your wall may begin to bow before the stud actually fails particularly if it wasn't/isn't secured into the rest of the building structure.

[Jonathan Spool]

Bruce is correct about the weak point of a stick framed 2x4 wall. This can be mitigated by sheatheing the wall with 1/2" plywood where the top of the sheeting is fastened into the top plate as well as to the studs. A sheathed wall, along with the fact that you are only extending out 12", and you should have no problems. I'm not an engineer, but did stay at a Holiday Inn last night!

[Brian Tymchak]

My problem is that I don't have a feeling for what a 12" high stack of lumber really weighs.

Bob

I found on a website that a cubic foot of white ash = ~50lbs.