Shelf Span Strenthening

[Ryan Froyd]

Quick question about strengthening a shelf. I am currently building a bookshelf/entertainment center. I am using Melamine for the shelving. The span is 30", the shelves are 12" deep and 3/4" thick.

I am using the sagulator to get an approximation of the sag. I have decided I will use 3/4" oak to put edging on the shelf to strengthen it. I have 3 options.

1. Put the oak on the front and use 2.5"x.75". Don't really like this option much, because now my shelves will appear over 3" thick, and they take up a lot of real estate

2. Put the oak on the BACK and use 2.5"x.75". I like this option, but whenever I look up strengthening shelves they always put the edge strip on the front of the shelf.

3. Put the oak on the front and the back, but rip the oak to 1.25"x.75". I like this option as well.

If I had time, money, and material I would make some samples and test them out, but I have very little of the above and was wondering if you kind people can offer some insight.

Thanks in advance.

[lowell holmes]

I would make the shelves out of oak or some other wood, not melamine.

[Ryan Froyd]

There are a couple of reasons I didn't use oak. First and foremost and almost $8 dollars a foot I would end up spending close to $160 on shelving alone. I can get by much cheaper with Melamine and Oak edging.

The other reason is that I am using premade white cabinets for the base of the entertainment center and we would like to continue the white through out the entire design. It would be criminal to paint an entire oak shelf white.

[lowell holmes]

Maybe poplar would be a viable option. In my area (Texas Gulf Coast), #1 commom poplar is $1.45 and select is $2. Poplar is an excellent paint grade wood. Our red oak is $2.55.

These prices are for rough. Milled 2S1E will cost an extra .50/bd ft.

[Craig D Peltier]

You could double the shelves up, you could also rout a groove across one and put a steel bar of sort in there towards front and sandwich together between melamines.
Melamine has no structural strength, its wood chips with glue, theres no real wood strands running opposite of each other, very weak for shelves.

[glenn bradley]

+1 on skipping melamine for shelves. Ply or solids will last where your particle board will fail if they are actually used to support weight. JMHO and probably not really helpful now that I think about it.

[Jeff Bratt]

Quick question about strengthening a shelf. I am currently building a bookshelf/entertainment center. I am using Melamine for the shelving. The span is 30", the shelves are 12" deep and 3/4" thick.

I am using the sagulator to get an approximation of the sag. I have decided I will use 3/4" oak to put edging on the shelf to strengthen it. I have 3 options.

1. Put the oak on the front and use 2.5"x.75". Don't really like this option much, because now my shelves will appear over 3" thick, and they take up a lot of real estate

2. Put the oak on the BACK and use 2.5"x.75". I like this option, but whenever I look up strengthening shelves they always put the edge strip on the front of the shelf.

3. Put the oak on the front and the back, but rip the oak to 1.25"x.75". I like this option as well.

If I had time, money, and material I would make some samples and test them out, but I have very little of the above and was wondering if you kind people can offer some insight.

Thanks in advance.

Add another vote for using anything besides particle board for shelves.

Plus two comments:
#2) The edging is often on the front for appearance - to cover up the plies or particle board of the shelf. You can put the strengthening strip on the back, and use something else on the front for looks - veneer tape, etc.
#3) using two strengthening strips (front and back) that are half as wide - will be much less stiff than your listed options 1 & 2.

[Ryan Froyd]

Jeff,

Since I am planning on using Melamine, I won't have to worry about covering up the front as the front of the melamine is white.

I know I am going against the grain by using melamine, but that decision has pretty much already been made.

Do you think the front of the shelf will sag if I have the oak edge in the rear of the shelf?

I don't think there will ever be a full encyclopedia set or anything near that heavy on the shelf, as my wife tends to put knick knacks ever 5 books or so:)

[Tom McMahon]

Melamine I believe is white particle board. With in a few months a 30" particle board shelf will sag noticeably with nothing on it, it sags under it own weight. The only thing giving your shelves strenght will be your edging.

[Kent A Bathurst]

1. Put the oak on the front and use 2.5"x.75". Don't really like this option much, because now my shelves will appear over 3" thick, and they take up a lot of real estate

2. Put the oak on the BACK and use 2.5"x.75". I like this option, but whenever I look up strengthening shelves they always put the edge strip on the front of the shelf.

3. Put the oak on the front and the back, but rip the oak to 1.25"x.75". I like this option as well.

Door # 1, Monte. Or, cut the span width, change the shelf material, whatever. The physical properties is what they is. Or, maybe dado the cabinet sides to receive the shelf ends, screws through the backs into the shelves, strengthing the entire assembly, and maybe you won't need 2-1/2" in front?

[Keith Westfall]

If you have a back on it, that will be a support, then perhaps a narrower front could be used. They do sag...

[Jeff Bratt]

Since you have decided on melamine/particle board, your shelf strength will come from the support strips. You could put a thinner one in front - for appearance and strength - and a thicker one in the rear - for lots more strength. There would be some tendency for the shelf to sag in the front if the support is only in the rear, but not nearly as much as the sagging in the middle of the span.

[Don L Johnson]

I just saw a couple of demos by David Marks. For shelving that was thin or spanded a longer distance, he uses torsion box designs. Get the thinnest material (thinner melamine would work) and make a torsion box; that should not sag at all and will hold quite a bit of weight. For that matter, resaw the oak and get more use out of it. David has some extremely thin torsion box shelves, ones that I would think would be too thin to help...but he said they work like a champ.

[Ryan Froyd]

Don,

Thanks for the suggestion. I plan on using torsion box's for 3 70" span shelves that will go over the tv.

I didn't want to build 8 torsion boxes for the 30" span I figured there had to be an easier/quicker way. My wife and I work full time+ and I have a 2 year old, so my time to work on the project is extrememly limited, building torsion boxes for the these shelves would have put my completion date somewhere around 2015!

Here is 2 of the ideas I am kicking around:

Side profile:
http://4.bp.blogspot.com/_hE-oGEZbZZ0/TFNkV6WzSaI/AAAAAAAAAx0/gtW6j3vW_TE/s320/shelfcrosssection.jpg

Or this one:
http://4.bp.blogspot.com/_hE-oGEZbZZ0/TFROinmXXBI/AAAAAAAAAx8/t3OXIHxg7tM/s320/shelfcrosssection2.jpg

[Howard Skillington]

Regarding the 30" shelves:
Not many people move "adjustable" shelves, once they've loaded them with stuff. If you dado and glue the ends (with that nasty Gorilla Glue, to adhere to your porous melamine), glue and nail the back edges, and properly attach about a 2" oak front edge, there won't be any side of the melamine that can sag. It's still lousy material for shelves, but it will be ok.
As for 70" long shelves, they're an altogether bad idea, regardless of material. Torsion boxes are your best bet, and you'd still do well to add a couple of vertical partitions between them - above the bottom one. If you want to use melamine for partitions, then don't bother, because they won't help.

[Jerome Stanek]

I woul se 1.75 tall .75 thick oak with a .25 x .75 rabbit in it and cover the front of the melamine.

[Howard Acheson]

>>>> Do you think the front of the shelf will sag if I have the oak edge in the rear of the shelf?

Depends on the weight. Adding a strip on the back of a 12" deep shelf will add little reinforcement to the front of the shelf. If the weight is concentrated near the front of the shelf, that's where the reinforcement should be.

[Jerry Solomon]

It's not the most elegant but you can also add vertical supports of the same shelf material. If you start at the bottom (assuming it's on something solid) you will get good support all the way up.

[ian maybury]

Just don't underestimate how little it takes for the stuff to sag over time.

My personal preference would be to design around very narrow 400mm approx wide shelves - maybe even buy them from Ikea and tweak them as needed: http://www.ikea.com/gb/en/catalog/products/40085714

[george wilson]

You have been warned.

[Don Alexander]

the strength to weight ration of melamine covered particle board is rediculously bad

however you can get white melamine covered plywood which would stick with your white theme and also provide alot more strength

just a thought:)

[Tony Shaftel]

I hesitate to mention this since the only one I'm aware of who's done it is me, but you might want to think about attaching a strip of angle iron along the front edge. I have done this in cases where appearance is not important, e.g shelves in the garage and a bathroom closet, but you might be able to doctor it up so it looks fine. It can be found with either a rounded or sharp bend angle. If you could find a piece with the right cross section you might be able to fit and paint it so that it is not particularly noticeable. I suppose you could also route a a groove and a slot an inch or so behind the front edge, so that a piece of angle iron with a smaller cross section, say half the thickness of the shelf, would fit flat against the bottom with the up-facing part of the angle inside the body of the shelf (glued with polyurethane glue, perhaps). In either case, I would attach it from the bottom with some screws to prevent weight in the middle from popping it loose.

[Bob Wingard]

One learns from his mistakes .. I predict you will come away from this project more knowledgeable.

[rick carpenter]

If you're going to paint the front support white to match the melamine, why not butt the front edge of the shelf to the support rather than butt the support underneath the shelf? No seam and that would cut down the thickness to the dimension of the support. You'll need to support the back of the shelf too but any way you do that will be less noticeable.

[Jeff Bratt]

I just assumed that you knew about the Sagulator (http://www.woodbin.com/calcs/sagulator.htm) - where you can estimate the sag for different shelf materials and loads. But there's the link if you didn't know...

Two 1.5" oak support strips will probably be OK for your shelves - wherever you want to put them. Either making the rear one larger, or attaching the shelf to the back of the case (non-movable) would give you a lot more support.

[Ryan Froyd]

First of all, thanks to everybody for your suggestions. I appreciate you taking time to reply to my posts. Here is what I ended up doing.

I have 8 shelves total. 4 of the shelves use melamine coated plywood, and 4 of the shelves are melamine. The melamine coated plywood I had laying around from a different project, but I was unable to find enough material to do all 8 shelves from it. Oh well, such is life.

I made a router table and routed 2 -3/4 inch channels, 1/4 inch deep on the underside of the shelves. 1" and 5" back from the front edge of the shelf. I then glued 1.25" by .75" oak strips inside the grooves and clamped them.

According to the sagulator these shelves should exhibit virtually no sag. I put the shelf load at 30lbs. per linear foot, which is far more weight then will actually be on them.

Since I glued them yesterday, I plan on taking the clamps off tonight and running a quick test on both the plywood and the melamine shelves to see whether or not the sag with weight on them. I will try to remember to post my results tomorrow.(I realize that they still might sag over time, but its impossible to do a quick test of that!)

Thanks again for your help.

[george wilson]

Quick test isn't going to work. They sag over time. Books are heavy.

[Ryan Froyd]

Understood.

Books are heavy, I agree. That being said, I have stated multiple times that they won't be fully loaded with books.

A quick test WILL determine what type of initial sag I will have in the shelf. If I put the maximum weight on the shelf(30-40lbs per foot seems to be average) and the shelf is already sagging past the point of no return (3/32" total) then I will obviously have to rethink my design. If however, there is no sag during the quick test, then I will be able to hang the shelves with more confidence.

[Caleb Larru]

One learns from his mistakes .. I predict you will come away from this project more knowledgeable.

Especially with the knowledge that melamine is really only good for shop jigs, small shop counters and sacrificial fences.

[Lee Schierer]

Put three length wise supports (front back and middle) under the shelf that are 1.25 x 3/4 (middle one would be dadoed in and be 3/8" shorter in height). The shelf should only sag about .02 with a 30 pound distributed load including shelf weight.

[Dave Houseal]

Good luck Ryan. IMO, just about any material can be a good shelf material if the engineering is sound.

I built two wall cabinets for my shop out of 1/2" particle board. They're each 5' long with 1 vertical divider which also gives me a 30" span also. Those cabinets are locked together like a jigsaw puzzle with all the dados. I added a 1/5" by 3/4" white pine face frame also dadoed, and those shelves are not going to bend or sag. They've been hanging on the wall for 2 years some with a pretty decent load on them.

Now my shelves aren't adjustable either, BUT...1/2 particle is doesn' even lay across a couple saw horses without sagging a few inches.

Now if they get wet, I'm screwed...lol...but I wanted cabinets and was on a budget, so you work with what you have. The doors on the cabinets are white pine with hardboard panels. The hinges were probably more expensive than the rest of the materials combined.

[Ryan Froyd]

Thanks Dave.

It is good to hear that someone has had some luck with particleboard.

My shelves won't be adjustable either. They will be screwed in on the sides, so that will help with stiffness.

In my old house I built shelves out of melamine and they held up fine over the 4 years they were there, so I have a quite a bit of confindence with these shelves as well.

I didn't quite realize there would be so much backlash over melamine material. I realize it is not ideal, but if you go into almost any store looking for shelving material 99.9% of it is some form of MDF. There must be a lot of saggy shelves across the US!

[Dave Houseal]

I didn't quite realize there would be so much backlash over melamine material. I realize it is not ideal, but if you go into almost any store looking for shelving material 99.9% of it is some form of MDF. There must be a lot of saggy shelves across the US!

Hahaha! There are a lot of saggy shelves...I'm sure of it. Really it isn't a great material...in fact its pretty lousy, but if you're conscious of that and allow for it you can certainly make it hold up. Those cabinets I made certainly won't be heirloom pieces that you might find grandkids fighting over 50 years from now, but they're holding stuff up quite well.

If I could have afforded something else I'd have done it, but money was tight and I made the PB work just fine. :D

[Steve Schoene]

Where are you that oak is $8 per board foot? That seems WAY high.

[scott vroom]

Ryan, according to Sagulator you're design should work.

Good luck.

[Ryan Froyd]

http://www.homedepot.com/Lumber-Composites-Boards/h_d1/N-5yc1vZ1xg2Zbqmc/R-100023293/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Granted it is home depot so it will be naturally higher than an actual lumber yard.

As far as location- South Florida, where everything is too expensive.

[Paul Johnstone]

Again, seriously consider plywood.. Even the grade B Oak plywood at the Borg at about 45-50/sheet would be much better.

I would think that the time/expense of building a torison box would negate any cost savings of not using plwyood.

If you must use Melamine, make the shelves fixed (not adjustable). Fasten the back to the back of the shelves with staples (from the rear of the shelves).. And put 1.5" of oak edge trim around the front. That will help.

Seriously though.. it will look better and be stronger to use oak plywood if you are using oak edging.. If you already bought the melamine, use it for something else.

[Chip Lindley]

...Do you think the front of the shelf will sag if I have the oak edge in the rear of the shelf?...

Ryan, if you put an oak edge on the rear, might as well put it on the front too. Then you have done all you can do, using particle board shelving. 3/4" thick shelving for a bookcase (IMO) tends to look kinda...well....puny! And, the rear edging will be too-visible on upper shelves. Oak edging on the front will add stiffness plus attractiveness to your project.

[Joe Chritz]

The sagulator gives directions for adding an edging option. Just plug in the numbers and see how it comes out with different options.

There isn't anything "wrong" with melamine as long as you understand going into it the inherent properties of the material. As mentioned, its sagging ability is legendary.

Joe

[Ryan Froyd]

Ran the quick test last night. Suspended shelf off of the ground on 2 2x4's at the very edge of the shelf. Placed 80lbs dead center. No sag.

So far so good:) I will try to post pics of the complete project when I am done if anyone is interested.

[Greg Portland]

Ran the quick test last night. Suspended shelf off of the ground on 2 2x4's at the very edge of the shelf. Placed 80lbs dead center. No sag.Be aware that particle board will slowly sag/bend over time. It might look good now but in a month you've got bowed shelves. This may or may not come into play with your design.

I just completed some honey-do shelves that I built with 3/4" Melamine and they are extremely solid. However, the shelves were 24" wide with a 1.5" support strip in front and the entire back and sides of each shelf were morticed to the casing (Domino was used but a simple dado would have worked too).

By the way, I hope you are building this entertainment center in sections and then assembling it in place (sounds like it's at least 6' wide and pretty tall?). You do not want to have to lift/carry that entire thing through the house (or doorway)!

[Cliff Rohrabacher]

The really nice thing about particle board is that it sags over time and under it's own weight. No need to put anything on it to get it to sag.

This should prove to be very cost effective over the long haul eliminating the expense of purchasing costly and breakable things to put on it to weight it down to get the desired level of sag.

[Ryan Froyd]

http://lh6.ggpht.com/_hE-oGEZbZZ0/THertXFBBrI/AAAAAAAAAy8/JL4f4eVgv3E/s800/011.JPG


http://lh4.ggpht.com/_hE-oGEZbZZ0/THervEd4I0I/AAAAAAAAAzI/fcFabhytPJ4/s576/014.JPG

[Dave Houseal]

Nice work! Good luck with the shelves...they look sturdy. :-)

[jackie gates]

:rolleyes::rolleyes::rolleyes::rolleyes: For any use of compsition material as unsuported shelving it is going to sag !!! If it is going to be on a wall use shelving tracks screwed to the studs, (studs O/C 16") and 12" brackets to place your MDF shelves At your desired vertical spacing. I have this type of shelves in my home office and they are still good after 25 years of heavy book use and no sags. Go to one of the builder supply stores and they will have the TRACK and BRACKET form of shelving. All material comes in various color scheme (white, brown, brass, etc.) Also they will have white Malimine shelves 12"X48". Before you build, research what is available, before you try to reinvent the wheel. :):) Cheers with your shelves. Jackie!

[Matt Armstrong]

Surprised nobody mentioned that two 1.25" strips aren't equivalent to a single 2.5 in terms of I value.

[Eiji Fuller]

Sorry if someone already suggested this. You can always laminate the mlamine with plastic laminate. Its really easy to do and you would practically be able to sit on it without sagging.

[Greg Portland]

Nice work Ryan! Are the shelves loaded up yet? Any pics "in use"?

[Gordon Eyre]

The kitchen cabinet shelves in my house were made out of Melamine (not by me) and they do pretty well except the bottom shelf where the plates are located. I doubled up the shelf gluing the two together and also anchored the back and after 6 months there has not been any noticeable sag. It seems a shame that these well made maple cabinet's in my house would use such a flimsy material for the shelves. By the way the interior of my shelves is MDF, not press-board as many are. I know that melamine coated MDF is available for purchase at my lumberyard and may be where Ryan is located as well. The front of the shelf will need to be covered with a heat activated white strip to match your current shelf as the melamine coated MDF just comes in 4x8 sheets not shelving size. It is very simple to put on the white strip in front.

[John Toigo]

You could rabbet the shelf into the back of the bookcase. However that means the shelf is not adjustable.

[Ryan Froyd]

Just a bump from the past to let you all know how everything is holding up. Well, it's still holding up! After a little over 3 years, no sag. I guess you can make shelves out of melamine, IF you do it right. I added some lighting from http://www.led-lighting-systems.net/controls.html.
276756276754276755

And my wife added various forms of knick-knacks.

276770

Sorry for the lousy photo, I'll take a better picture tonight if anyone is interested. I was going through my favorites and stumbled upon this thread, so I just posted pics I had on hand.

[Bill ThompsonNM]

Nice work, And glad to hear they are holding up well.