Modular Rack Design and Build-out

The How and Why?
So I'll start off by explaining why I decided to go through all this hassle and trouble of creating a storage rack design from scratch. Basically, what you can buy out there at the big box stores (i.e. HD and Lowes) quite frankly sucks in terms of quality and durability. I got some of those tough bent-steel racks (Muscle Rack Shelving Unit) that purport to hold up to 800lbs per shelf. Bullshit. First off, the quality is lacking. The shelving boards are particle board that were 1/4" longer in length causing them not to fit it into the shelf supports. Second, some of the legs were bend out of the box. I ended up having to straighten out half of them. What would have been an easy 15 minute setup took an hour, and ended up with a hacksaw and a rubber mallet. And it still doesn't fit. It's in the basement corner holding up bags of salt for the water softener, and its starting to bow in the center. The saving grace, I got them for $30 on Black Friday instead of the listed $78 as of this writing.

Ok, enough ranting, on to the How. I spent some time researching designs that were out there on the net and some were just overly complicated with these intricate cuts, lap joints, routed channel supports, etc. I had tried some of these approaches in a past design and without the support of some higher end tools, it failed miserably. The engineering just wasn't there. Below is the design and plan with measurements for this particular build-out. I ended up taking the same design and expanding it for use in the garage as a larger storage rack system. So these were the criteria for this build:

• Made using commonly found structural lumber and materials (2x4s, 4x4 posts, plywood, etc)
• Least number of cuts resulting in less waste
• Can be built using basic power tools
  
• Modular and can be expanded/extended

By using structural lumber, the shelves will be as strong as the same material holding up the roof over your head. Plus, 2x4s can easily be found in any home improvement center in the lumber yard or department. FYI, structural lumber stated as 2x4 isn't actually 2 inches by 4 inches. All measurements are short 1/2". Why? I don't remember the specific reason. Wikipedia has a good article explaining it. So basically a 2x4 stud measures 1.5"x3.5". The plans reflect this reality.

Design and Materials
This isn't going to be an intro to DIY and I'm going to assume you have some knowledge and common sense in working with your hands. So my plans (or this article) will not be a step-by-step guide; cut this, hold this like this, screw this in, etc. With that said, I take no responsibility if you decide to drink and end up chopping off your hand. And don't be a dud. Wear eye and ear protection. Can't work on future projects if you're missing an eye. Ok, maybe you can. It'll just be harder.

Tools. It's what separates the men from the boys. Right.. whatever. I'm like most people. I buy tools to do it myself and by saving money not paying someone else, I end up with a set of tools. With that said, I don't have some of those more specialized tools. Like a table saw. That would have been helpful in some other projects. But I make do with some clamps and a circular saw. For this build, all you need tool-wise is a pen, tape measure, safety equipment (eyes, ears, and hands), power drill and some type of saw to cut the wood. I have a miter saw which made these straight cuts really easy. If you don't have one, wait till Black Friday to score one cheap. Some other things that helped make this build (and future ones) much easier; a speed square and some quick clamps.

Using sketchup, I drafted these plans with measurements. I've included all the necessary views and measurements for this build. If I missed something, leave a comment.

Front View

You're standard view from the front. I couldn't figure out how tall the woman is in SU. I figure she's about 5'5" or 5'6" (average?). I didn't muck around that long to try to find out.

Rear View

Note the rear supports to keep the rack from, well, racking (laterally moving side to side). I wanted to keep both the front and the back accessible for easier loading. This is a free-standing rack in my basement pantry so things get loaded from all sides. The "proper" way to have engineered this would to have diagonal cross braces for the lateral loads. Modify to suit your needs.

Frame and Shelf Supports

Again, made up entirely of structural lumber commonly found. I set the height of each shelf so that it would minimize bending and lifting. The middle two shelves are at thigh and chest heights. A note on assembly; each shelf support is screwed into it's respective post using 4 screws. I suppose you can go with 3, or get away with 2. I used four to test a theory. More about that in the material section.

Shelf

The shelves themselves are made of some cut 2x4s and a section of cut plywood. Again, common sense assembly here. Where two boards intersect, screw it. The top is screwed down to the base. The shelves themselves are not screwed to the post. That would negate the shelf supports and you can't drive that many screws in that smaller corner. Once the shelf was on the support, it won't really slide in or out. You could add some small metal plates to hold it in place; something like a stop-block. 

Raw material-wise, for this particular build-out, I went to home depot and purchased the following:

• 13 2x4x8 studs (Douglas firs) @ $2.39 ea = $31.07
• 4 4x4x8 posts (Douglas firs) @ 10.39 ea = $41.56
• 1 7/8x4x8 sheet of plywood (cabinet grade) @ 29.97
• 2 boxes of construction screws (2 1/2" and 1 1/2" SPAX) @ $7.97 ea = $15.94

Some notes on the material. The douglas firs are a renewable resource (they grow relatively faster) and were only 10 cents more expensive than the other 2x4x8s. Plus, these ended up looking nicer (less knots and splits). Home improvement centers will usually cut up sheet goods for you. I had them rough cut a standard 4x8 sheet into four equal sections. Four 2x4 boards. Handy huh? Each cut sheet fit directly onto an assemble shelf structure. No extra cutting needed.

SPAX screws

Regarding the screws, I was asked if I had used lags. The short answer is no. The reason is because I didn't want to pre-drill all these holes and the loose a'la carte lags for sale could have been Grade 2, but made overseas so the quality could be questionable. So I found these SPAX brand screws at the Home Depot. I actually ended up using the whole box and was short one screw. Well, there was one defective screw, other-wise it would have been perfect. Anyway, I found these screws to have several benefits. You don't have to pre-drill as the design of the tip has a cutter. The top end of the shank is non-threaded which helps "pull" pieces together. And the star-drive was just a big win. No slips plus it included a free bit. Now here is the best part (and my theory). Do these have to same shear strength as graded lags? The back of the box said they have been tested to 350 lbs shearing limit. The recommended safe work load is 25% of that. So, each shelf has 4 screws in each post @ 4 posts, for a total of 16 screws or a shear limit of 5,600 lbs or a safe working load of 1,400 lbs per shelf. FYI, the compression strength of douglas fir is tested to be some 7,200 psi. The point of failure in this particular build out would be the lateral shifting. In this particular case, I mitigated that by strapping it to the exposed ceiling/floor joist.

Build-out

Here are some pictures of the actual build out. All materials were moved into and assembled in the basement. It was heavy for a 1 person job.

Shelf structures assembled.

Vertical supports assembled. Free standing.

Final assembled storage rack. Need to buy more now for Dec 21st.

So all this really started with a design for a modular rack system. The following is a design based on this one that was easily modified/extended. It'll serve the basis of a larger rack storage system in the garage.

Front view - Larger Rack system

Bottom View - Larger Rack System

Total Time: 6-7 hours spread over a few nights

Cost: ~$118 (before taxes)

Closing thoughts: Yea, this was way WAY over engineered for a simple pantry rack. Some of the elements could have been scaled down. However, the goal was to test the design of a modular rack system. The next one will be going in the garage to hold things like my tools and seasonal tires.