framegaragemountingscrewsshelving
We have built the typical free-standing 4-level garage shelves(similar to this) & want to secure it to the house frame in the garage.
The whole thing is pretty sturdy but we just want to be safe & this is in California, where there is a threat of earthquakes.
What kind of screws do you recommend & how long should they be?
Maybe 1-2 screws per shelf to the frame?
Here is a photo & rough estimate of the measurements:
Since you are contemplating shelving, I am going to assume that
I've got a shelving unit in a storage area that can fit at absolute maximum volume capacity about 24 of these 10 gallon storage bins:
With all 24 on the shelves, I physically cannot add any more weight to the shelves because all of the volume is already consumed.
I estimate the maximum weight that I put in each of those bins is about 50 pounds of stuff. From moving them around and comparing them to the dumbbells at the gym, it's way more that 20 pounds and definitely less than 100 pounds. As a reference, filling the tub with water would weigh 81 lbs, filling with lead is about 946 pounds.
So, based on my estimate, I will be storing up to about 1200 pounds (24 tubs x 50 pounds each) of stuff on that shelving unit. More than 1200 pounds is unlikely because the shelf will reach its volume capacity first.
In this case I dare not use a shelving unit that will collapse under less weight than 1200 pounds because there will be nothing preventing an unsuspecting family member from exceeding that weight by adding another item to the shelf.
The shelving unit in the example above is 4'x2'x8' (WxDxH) or 64 cubic feet. Given the 1200 pound capacity, the density of stuff I am storing works out to 18.75 pounds per cubic foot. When I design shelving for my home, I use the round number of 40 pounds per cubic foot for a 2x safety factor.
For your example of 1.5'x8' shelves, assuming they extend to an 8' ceiling, you should design for an astounding 3840 pounds of load (1.5'x8'x8'x40 pounds per cubic foot) to be safe. This is not an exaggeration. Good shelving allows you to store a remarkable amount of weight in an extremely small volume, that is its whole purpose after all.
The stuff you are storing on wall mounted shelving is an overhung load. The wall mount shelving supports this overhung load by applying a torque to the wall to which it is mounted. Walls in residential construction are not designed to support a significant amount of overhung load.
To make matters worse, the torque on the wall increases with the square of the depth of the shelving because you are increasing both the weight and the lever arm of the overhung load. So, the torque from an 18" deep shelf is nine times the torque from a 6" deep shelf. Because of the squared relationship with torque, I never use wall-mount shelves deeper than 10".
On top of all this, even if your wall is able to withstand the torques involved, there are two additional worrisome aspects to consider:
A real risk is this scenario: A child climbs a wall mount shelf loaded with hundreds of pounds of stuff. The weight and motion of a child causes the multiplied forces in the bracket to exceed the failure strength of the bracket. This causes a catastrophic failure of the shelf's ability to support the load, and the child and load falls to the floor, crushing the child.
All of the problems that results from multiplying forces, the squared relationship of torque with shelf depth, and a wall that can't support weight are alleviated by using free-standing shelving.
I recommend using a properly engineered system like EZ Rect Type 1. It looks like this:
As I understand it, the EZ Rect system's patent has long expired, and there are now many manufacturers of that system. I've been using a generic version of that system for all my high-density household storage for almost 10 years.
Here are the benefits of EZ Rect Type 1 shelving solution as I see it:
Whatever system you end up with, you should expect the above benefits to be standard -- if it's not, keep looking.
Here is a picture from my last moving day. Shown is 7 "bays" of dismantled shelving capable of safely storing about 24 tons (42,000 lbs) in about 600 cubic feet of space.
I've encountered an amount of skepticism about whether catastrophic failure of shelving is, in fact, something to be concerned about. Here are two examples of catastrophic failure.
A worker died in this workplace accident in 2012 when an overloaded shelving system collapsed.
This is an extreme case of what can happen. I think it is instructive of the dangers nonetheless.
The great Jon Skeet tweeted this photo of what seems to be catastrophic failure of a wall-mount Cookbook Shelf:
Depends on overall design and load, and, in terms of screw/nails, it depends on what will be anchored to what. A floor plan annotated with fastener locations would help.
If you are notching in order to transfer load to the 4x4, a 1/2" deep notch is all that is necessary. Notching will take shear stresses off the associated screws/nails/bolts.
EDIT:
Great new drawing.
The main design considerations are the unit racking and collapsing (side to side), or the units tilting forward and falling over. Attaching the units to the back-wall in a couple places will stabilize the units, particularly their back portions. If the 1/2" OSB is screwed/nailed to the front and to the back 10' 2x6's, then the back-wall attachment will also stabilize the front portions of the units as well. If units can be attached to an end-wall, then attaching to both back and end walls will fully stabilize the units without needing to screw/nail the 1/2" OSB to the 2x6s. If back and/or end wall attachments are not feasible, I'd place 2x4 cleats on the ceiling and secure the 4x4 posts to those cleats.
On both the front and back, I'd put the 10' 2x6s on the inside of the posts, notching the posts 1/2" deep. This will give more support to the 1/2" OSB over the 24" dimension. Another benefit of internal attachment is that the 2x6s will be recessed 3" from the outside edge of the 1/2" OSB and 4x4s. Given that, you'll be able to hang all kinds of small things on the outside face of the front 2x6s without the items sticking out. You could also screw 4.5" wide lengths of 1/2 OSB (or anything similar, such as 1x6) to the underside edge of the 2x6s to create 3" deep shelves for light weight items.
If one end of the unit is open (such as facing the garage door, I'd consider moving the two 4x4 end-posts inward 16-30", which would cantilever the ends of the 10' 2x6s, creating 2-sided open access to the cantilevered portion of shelving.
The 5.5" of space immediately underneath the shelves will be kind-of wasted space. If one end of the unit is open, then I'd attach 24" wide OSB underneath the 2x6s to create deep pockets (cubby holes) open on that one end, for storing long stuff. The 24" long 2x6 end-caps can be under-mounted or top-mounted.
Best Answer
I'd go two screws per wall stud thru the top and middle shelf. The weight of the thing is supported by the structure itself so all you need to do is keep it from falling over. Use a 4 1/2 inch timber tech or a 5/16 lag with a washer and you'll have two inches of screw into the stud which is adequate but a minimum. Make sure you install shims or a spacer to fill that gap before you run your screws.