Shelving query - what thickness of birch ply?

[PhilipL]

I have moved and brought many. many books with me - including heavy ones. The removals boys suggested an iPad would have made their job much easier.

My plan is a wall of shelving and I have just ordered elfa twin slot shelving uprights and brackets to space at 18" centres. In the past I have used mdf with oak on the shelf front to increase strength. Planning to use birch ply without any fronting. Could I get away with 12mm or should I go for 18mm? Shelf width will be 12".

Philip

 

[Noel]

No Birch ply, only soft but might give you an idea:

https://woodbin.com/calcs/sagulator/

 

[PhilipL]

No Birch ply, only soft but might give you an idea:

https://woodbin.com/calcs/sagulator/

Very useful. Looking at that I might use 18mm for lower shelves and 12mm for upper ones. The cost of ply!!

 

[Spectric]

Depends upon how you want the final look. 18mm MDF indoors is showing signs of sagging but 12mm ply in the garage is not, the difference is that in the garage the ply has 2x1 battens front and back between the supports.

 

[Jacob]

Softwood stiffer and cheaper than ply.

 

[Stuart Moffat]

I too would go with softwood, but I make all shelves carrying a load using sliding dovetails into the sides. (Various ways of doing it but I have an old router permanently mounted on a littleRat. A load on one shelf wanting to sag goes into tension against those sliding dovetails. None of them have ever sagged at all.

 

[robgul]

I'd certainly consider softwood rather than sheet material - or even (new) scaffold boards with a bit of planing and/or sanding look pretty good with a light stain applied. If you do go for Brch ply then 18mm would be my choice.

 

[Richard_C]

With the price of any wood as it currently is, it would be an interesting sum to see if spending more on having more brackets and less on using thinner shelves might make sense. My home office has some very heavy stuff* on white painted 18mm MDF, but the shelving uprights are c 12 inch centres, no sign of sag after many years.

I find it hard to part with books, and CDs and vinyl records and DVDs ...and etc. but many people seem happy with e versions of everything. I guess we fill the space available however big or small that might be. If you live in a small modern house it must mean a Z gauge model trainset, not 00, for your children.


* featuring frighteningly full foolscap files.

 

[PhilipL]

With the price of any wood as it currently is, it would be an interesting sum to see if spending more on having more brackets and less on using thinner shelves might make sense. My home office has some very heavy stuff* on white painted 18mm MDF, but the shelving uprights are c 12 inch centres, no sign of sag after many years.

I find it hard to part with books, and CDs and vinyl records and DVDs ...and etc. but many people seem happy with e versions of everything. I guess we fill the space available however big or small that might be. If you live in a small modern house it must mean a Z gauge model trainset, not 00, for your children.


* featuring frighteningly full foolscap files.

Each upright (2400mm) and 7 brackets (for 12" shelves) is working out at around £24. You would be adding an extra 4 of these (are my sums ok?) at 12" centres. 18mm birch ply is about £110 (it seems). Not sure how much softwood would be. Interesting to see what the most cost efficient system would be.

 

[johnny]

interesting question ....I too have lots of books accumulated over the years which I'd hate to part with so I understand your dilemma.
I think the materials should be dictated by your design and that will be largely be dictated by whether you will have fixed or adjustable shelving.

Simply put ,if the ends of the shelves are fixed (ie glued into grooves ) they will resist deflection (sag) whereas shelves sat each end on simple supports, (adjustable), will have zero resistance to deflection other than that provided by the thickness and composition of the shelf material together with the proposed shelf length.

Its all about the ratio of the thickness of the material to the proposed length. leaving weight of material aside, the thicker the shelf or the shorter the shelf the stronger it is going to be and the greater resistance there will be to deflection (sag) In the real world increasing the thickness of the material to resist deflection actually adds to the problem because more self -weight increases deflection..!

A simple way to overcome this problem is to either groove and glue the shelf ends or to brace the shelf front edges with a 2" nosing which in my view always looks better than a thin shelf edge on view . A nosing could allow you to use a lightweight ply 12mm shelf over a width of a metre or even 1200mm
https://www.woodsmithplans.com/plan/traditional-oak-bookcase/

 

[recipio]

It really comes down to aesthetics and function. I don't like the upright and bracket system as the books have no lateral support. If you have to use them then mixing 18 and 12 mm ply seems like a good idea.. A dedicated 'bookcase ' always looks better and I make mine as 16" 'cubes' No need for variable shelves, I find pocket holes covered with the plastic covers perfectly acceptable. For a really stiff shelf I resort to flush doors which can be cut on the tablesaw and the exposed ' eggbox' interior supported by a softwood batten glued between the outer skins. Finding nice flush doors is of course another problem

 

[Richard_C]

We had a couple of Ikea floating shelves in the children's rooms, they were eggbox construction, very light and very very stiff. A bit labour intensive for diy though.

 

[PhilipL]

It really comes down to aesthetics and function. I don't like the upright and bracket system as the books have no lateral support. If you have to use them then mixing 18 and 12 mm ply seems like a good idea.. A dedicated 'bookcase ' always looks better and I make mine as 16" 'cubes' No need for variable shelves, I find pocket holes covered with the plastic covers perfectly acceptable. For a really stiff shelf I resort to flush doors which can be cut on the tablesaw and the exposed ' eggbox' interior supported by a softwood batten glued between the outer skins. Finding nice flush doors is of course another problem

Lateral book support comes from the end walls. Bookcases really don't swallow the same number of books as library style shelving. I will probably end up with 25m or so of shelving in my proposed build.

Yes, nosing was always my chosen option in the past. Unfortunately the workshop has gone as I downsized to a flat, so birch ply seems a good option since it presents a better front edge than mdf.

 

[recipio]

Lateral book support comes from the end walls. Bookcases really don't swallow the same number of books as library style shelving. I will probably end up with 25m or so of shelving in my proposed build.

Yes, nosing was always my chosen option in the past. Unfortunately the workshop has gone as I downsized to a flat, so birch ply seems a good option since it presents a better front edge than mdf.

I take your point and without a workshop its going to be difficult reducing 8 x 4 sheets of anything. Softwood shelving pre cut and sanded is probably going to be your best option if not the cheapest.

 

[PhilipL]

I take your point and without a workshop its going to be difficult reducing 8 x 4 sheets of anything. Softwood shelving pre cut and sanded is probably going to be your best option if not the cheapest.

Where I was in NI building merchants would cut sheet down to size. Surely they do it everywhere?

 

[mikeprevette]

Stair Treads are a good "precut" option that are fairly rigid. I've also been building basic torsion box shelves with 18mm x 18mm ply battens as a core with 6mm MDF top and bottom, and a poplar front edge. They are very rigid, and light at the same time, doable without a shop, but not fun.

 

[Cabinetman]

Torsion box shelves— My only foray into Oak faced MDF for furniture making was a triple bookcase, two sheets of six mil with half inch pine strips running along the length inside and an Oak nosing for each shelf, I never did it again it took forever to make so worked out far more expensive than solid oak, and fairly obviously why would you have MDF when you can have solid oak. Ian

 

[PhilipL]

This is towards my goal but I have many more books than this. About 10 foot square of book shelving - a whole wall of books and then probably part of another wall. Some of you don't understand the misery of book collecting!

Edit: As a PS when I retired I sent about 800 books down to the charity shops from my office.

 

[thetyreman]

pine is perfect for shelving, very lightweight and strong, preferable to plywood, I'd go with 18mm or thicker. Poplar could be a good choice if you are planning on painting them.

 

[Richard_C]

Just been for a wander round the house, I've got c 46 running metres of books spread among various room, shelves, cupboards and bookcases. There are a few boxes in the roof as well. My next job should be to look up some actuarial tables, work out how many years I might have left and how many hours of reading I have on those shelves and start a proportionate clear out. Some of them are reference so you never read them cover to cover so might get kept. I guess my Newnes Engineering manual 1968 is irreplaceable, and where else would you look up the weight of steel removed by a drill tip of various diameters, or the density of common hardwoods or....

My dream solution would be to have all of them on proper floor to ceiling wall shelving in one room with one of those library ladders that hangs from the top and can be slid left and right as required. Plus one comfortable chair. Hmm....

But back to the OPs original question - in the absence of a workshop, softwood seems to be the consensus. I wonder if internal window cill/sill/board section which is bullnose and typically 3/4 or 1" thick might be an answer: no idea of price. If you can get the costs down you might have enough left over for one of those magic ladders - like this .

https://llcompany.co.uk/pages/the-ladder-range
(to sleep, perchance to dream..of library ladders?)