LumberJocks

Lumber rack concerns

  • Advertise with us

« back to Safety in the Woodworking Shop forum

Forum topic by Phalanx1862 posted 07-30-2019 04:02 PM 595 views 0 times favorited 11 replies Add to Favorites Watch
View Phalanx1862's profile (online now)

Phalanx1862

10 posts in 79 days


07-30-2019 04:02 PM

Hey folks, I don’t know how many times this has been over before, but my search on the site has only brought up a few entries, unless I’m doing it wrong. I would like to make a wall mounted lumber rack for the wall between my garage and my living room. Much in the same vein of Jay Bates’(2×4 secures to studs, with conduit or steel pipes sticking out around 12”), though I only expect mine to be MAYBE 3 tiers high, but mounted around 6 feet up. I also would like to put a workbench that folds up and hangs on the wall under that. I guess the question I’m getting at is how much weight is safe to put on the wall in this situation? I’ve read elsewhere that hanging too much weight at 12” from the wall may have introduce a rotational force on the top of the wall, but I don’t think most of the weight would be concentrated at the end of the conduit. I have seen many tutorials on YouTube as well as even plans from popular woodworking for a lumber rack of this nature, so I should think that it would be safe, I’m just a big worrywart about most things. Anyways, I would love if y’all would weigh in (awthankya) on this lumber rack as well as the fold up workbench under it. Am I trying to do too much, or am I worried for nothing?


11 replies so far

View CaptainKlutz's profile

CaptainKlutz

1748 posts in 1973 days


#1 posted 07-31-2019 04:48 PM

Hmm, good question!

I have mounted a pair of 6 tier, steel lumber racks (like these) to my garage wall, one on top of other, staggered by one stud. Then loaded them up with ~450bd ft of lumber, that weighed over 1500 lbs on the trailer. Using a proper fastener (lag bolt 1/2 way into stud) to get load into the wall, it worked without failure?

Depending on who you ask, and what assumptions used in formula; a single vertical 2×4 can supposedly hold 500-700 lbs (assuming it is sheathed both sides). A rule of thumb I have used for years is: up to ~1200 lbs static load, evenly distributed across a 4ft+ long wall (3 studs on 16” centers) is usually OK?

When considering an entire wall, the calculations require knowledge of existing roof load, and external side/wind loading. It’s a little complicated? If you want a definitive answer, you need to do some research and lots of math, or hire an licensed architect and have them calculate specific loads your walls can handle?

Grabbed these random WWW links to get you started:
https://www.eng-tips.com/viewthread.cfm?qid=92870
http://www.wwpa.org/resources/?topics=dfae6d8f-ad3b-6952-b602-ff00000b7aec

Best Luck.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View pottz's profile (online now)

pottz

5954 posts in 1463 days


#2 posted 07-31-2019 06:05 PM



Hmm, good question!

I have mounted a pair of 6 tier, steel lumber racks (like these) to my garage wall, one on top of other, staggered by one stud. Then loaded them up with ~450bd ft of lumber, that weighed over 1500 lbs on the trailer. Using a proper fastener (lag bolt 1/2 way into stud) to get load into the wall, it worked without failure?

Depending on who you ask, and what assumptions used in formula; a single vertical 2×4 can supposedly hold 500-700 lbs (assuming it is sheathed both sides). A rule of thumb I have used for years is: up to ~1200 lbs static load, evenly distributed across a 4ft+ long wall (3 studs on 16” centers) is usually OK?

When considering an entire wall, the calculations require knowledge of existing roof load, and external side/wind loading. It s a little complicated? If you want a definitive answer, you need to do some research and lots of math, or hire an licensed architect and have them calculate specific loads your walls can handle?

Grabbed these random WWW links to get you started:
https://www.eng-tips.com/viewthread.cfm?qid=92870
http://www.wwpa.org/resources/?topics=dfae6d8f-ad3b-6952-b602-ff00000b7aec

Best Luck.

- CaptainKlutz


ive done similar and have never had an issue or even worried about it.unless your talking about huge amounts of lumber weighing thousands of pounds you should be fine.if say you have a 1000lb of wood and spread it over 6 studs your only talking about 167lb’s per stud.

-- sawdust the bigger the pile the bigger my smile-larry,so cal.

View SMP's profile

SMP

1335 posts in 384 days


#3 posted 07-31-2019 06:09 PM

I would say, if you get to the point where you are worried about the weight of all the wood you are storing—- GO BUILD SOMETHING WITH IT!

View pottz's profile (online now)

pottz

5954 posts in 1463 days


#4 posted 07-31-2019 07:10 PM



I would say, if you get to the point where you are worried about the weight of all the wood you are storing—- GO BUILD SOMETHING WITH IT!

- SMP


LOL-totally agree,when my racks get full i stop buying more or start building more,problem solved.

-- sawdust the bigger the pile the bigger my smile-larry,so cal.

View bilyo's profile

bilyo

818 posts in 1581 days


#5 posted 07-31-2019 09:16 PM

These are 15” long 1 1/8” OD rigid conduit press fit through holes in 2×4s that are in turn lag screwed into the wall studs. Holes were bored with 1 1/8” forstner bit. Screws were run in horizontally above and below each hole as a precaution against splitting. Vertical spacing is 12”. The lumber is cherry and walnut. They have been loaded like that (not the same lumber) for many years with no issues.
I didn’t do any complicated calculations. But, I did build a mock-up and load tested it before the final build. Of course, the tests proved it could carry the load.

View ibewjon's profile

ibewjon

897 posts in 3271 days


#6 posted 07-31-2019 10:22 PM

Have you noticed any bowing in the inside of the studs / drywall?

View bilyo's profile

bilyo

818 posts in 1581 days


#7 posted 07-31-2019 10:44 PM

2×4 stud wall with drywall. I have not noticed any bowing.

View Rick  Dennington's profile

Rick Dennington

6625 posts in 3673 days


#8 posted 07-31-2019 11:40 PM

I’ve got the same racks as Capt. Klutz….Had it for years, and never had a problem with it. As long as you use heavy-duty lag bolts screwed into the 2×4’s, and the “arms” are locked in good, you’ll be fine. These things will hold a lot of wood.

-- " The secret to staying young looking.....hang around old people.." R.D.

View Phalanx1862's profile (online now)

Phalanx1862

10 posts in 79 days


#9 posted 08-01-2019 11:28 PM

Wow! Thanks for all the replies! I felt like everything should be fine, but worrying seems to be my reason for being. I appreciate y’all putting my fears to rest.

View coxhaus's profile

coxhaus

145 posts in 1373 days


#10 posted 08-03-2019 08:38 AM

I built this rack from square steel tubing. It is mounted to a brick wall inside my garage.

View clin's profile

clin

1056 posts in 1474 days


#11 posted 08-03-2019 04:33 PM

Just to put a some numbers on this, so you can have additional confidence that it is okay to do. It’s reasonable to assume your load will average being half the “shelf” width. So with your 12” deep width, that’s 6 inches.

Let’s assume 1,000 lbs of total load. What the OP referenced to as a rotational force will be there. The actual name for this is rotation force is “moment.” It is also essentially the same thing as a torque. In this case, if we assume a 1,000 lb load that averages being 6” from the wall surface, we have to add on the distanceto the center of the wall. Let’s say another 2 inches. So, the entire load is 8” from the center of the wall.

1,000 lbs 8” off center creates a moment of 1,000 lbs x 8 ” = 8,000 lb-in = 667 foot-lbs.

This is the force that is trying to pull the wall over. It may seem like it is a lot, but is not. A moment can be calculated around any convenient point. In this case, it makes sense to assume the bottom of the wall which we can assume is well attached to a slab, footing or other structure.

What’s keeping the wall from being pulled over is the support at the top of the wall being provided by the roof structure, such as trusses. We have 8,000 lb-ins of moment from the load that must be resistance by a force at the top of the wall. If the wall is 8 ft (96 inches) tall, then this force is 96 inches from the bottom of the wall. You can think of this as the length of the leverage need to offset the moment created by the load.

Therefore the force at the top of the wall will be 8,000 lb-in / 96 in = 83.3 lbs. I think it is obvious just how trivial that load is. This would only be an issue for a wall that is pretty much not even attached at the top. Presumably your wall is securely attached to your roof to where 83 lbs would easily be resisted. Similarly if you had 2,000 lbs, you could just double this.

Now, this is just a simple way to determine total force on the top of the wall for an ideally rigid. Real structures flex and exactly where the load gets distributed is more complex. But again, for an 83 lbs load in a structure, this is trivial even if all of it were in one spot.

There are of course other concerns about bowing the wall, but the bending moment is this same amount and I think it’s easy to see how 83 lbs even applied at the end of a single 8 ft 2×4 on edge isn’t going to bend it very much. And the load is going to be distributed along multiple studs.

Here’s another non-math way to look at this. Kitchens have large numbers of wall cabinets. Often loaded with very heavy dinnerware plus the weight of the cabinets themselves. These cabinets are often 12” deep (same as what you are considering) and sometimes much deeper. I’ve never heard of a kitchen wall failing under these loads. Agreed, you may end up with more load than this, but probably not that much more.

It’s good to think about these things and not assume it will be okay, but I think for a small wood rack, you’re going to be just fine.

-- Clin

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com