Long shelf for heavy books

[Ian Moody]

Hi people,

I signed up to ask a question, but since then have had a re-think and might not be going this way, unless any of you fine folk can give a easy suggestion.

What I need is basically a 'floating' deep shelf for heavy oversized books that is 3.4m long, without using a central support.

I can support it at both ends and along the rear, but the front needed to be unsupported.

Does that even sound possible?

My back of the envelope calculation put the overall weight of books at round about 100 kilos.

I think it will al be too much really and that I just need to move the furniture around and do a simple standard shelving system, unless you have any cunning plans?

Ian

[Ben Rivel]

Thick shelves and a thick backer board with the shelf running in a dado in the backer board and hard wood edge banding on the front edge of the shelves I think its about as good as can be done. 3.4m (~11ft) is a long shelf.

[Bradley Gray]

I made some "floating" shelves for a client once. The architect called for 1" pipe set into holes drilled in the studs extending into holes drilled in the back of the shelves.

I made a drill guide on the drill press to locate the holes vertically and keep them straight.

[Adam Herman]

you can make a kerf cut with a circular saw and a shallow dado to insert a steel angle along the front and keep it mostly hidden. steel pipes sticking into studs and the shelf is also an excellent idea. you could also make a bracket that goes up at an angle. like a shelf bracket below, but put it above, it will be mostly hidden by the books. Above eye level on floating shelves, i put my fasteners on the top so that they are hidden.

[Ian Moody]

Thanks for the replies - am I right in thinking that this is definitely on the 'engineering' end of the spectrum as opposed to the 'simpler' traditional DIY type project? I like the idea of having inverted supports, hidden by the books themselves - that's the kind of cunning plan I was after. I was also thinking that if i needed another smaller (less deep) shelf above for lighter paperbacks then I could make some kind of vertically stretched torsion box, where the box was actually deep enough to contain a row of books.

[Mike Cutler]

Ian
Can your design criteria accept three upright supports. Each about an 1 1/4" square that are removable? These would be hidden by the books.
I have a modular, knock down,bookshelf that is 10' long, 30" deep, and 8' tall. This one is free standing.
Your choice of wood, and it's stiffness will be important. You will have to incorporate some hidden metal.
You need to spread that load across the bearing verticals, or you risk overloading your floor rating, unless the shelf is on concrete. Attaching it to studs had to be carefully considered also, or you risk breaking studs.

[Alan Lightstone]

... or you risk breaking studs.

You can break a stud????!!!???

[Steve Peterson]

You can break a stud????!!!???

Drilling a 1" hole in a stud would sure weaken it a lot. A 1/2" hold in the center is probably OK.

Steve

[Charlie Fox]

without knowing exactly how the ends and rear are supported as well as the type of wood and thickness that can be accommodated i just dont see how anyone could answer this question. I am quite certain I could engineer a 4" slab of oak or pecan that would work quite well given the right end and back support - but that is an unknown at this point. am i missing something? not a mechanical engineer but i did stay at a Holiday Inn Express a couple of times this year - and i raised my son to be an ME so maybe I am not quite that far off.. ;-)

[Bill Conerly]

A fun project would be to set up a stud in the shop. Put a pipe into it. Then see how much load you can put on it before it breaks. Have a few beers first.

[Ian Moody]

Walls are 1/2 inch of very old plaster over what I believe to be two deep brickwork followed by cavity followed by exterior portland stone (it's a strange old house). To be honest this is sounding like such a bigger job than I imagined that I just need to accept that I should make my life easier, move the lounge around, and plop a couple of floor mounted stock shelving units in. There is a tonne more stuff we need to get sorted, including attaching a climbing wall to one of the kids bedroom walls (that is a nice simple stud wall) that I think I should just pick a different fight, if you know what I mean.

[Kevin Jenness]

A torsion box with a pocket in the back edge slipped over and screwed to a ledger attached to the brick with Tapcons. At that length the unit will need to be spliced for length or made in two pieces. 1 1/2" square ledger, 1/4" skins with a buildup at the pocket for screw holding, 1/2" core grid 4" on center, solid edging, veneered or not as you like it, 2 1/2' thick, no end supports required. Make sure the ledger is solidly attached to the wall and plenty of screws through the top into the ledger.

[Mike Cutler]

You can break a stud????!!!???

Yep.
You should see what a 425 gallon fish tank can do to a wall, when it's weight is only carried by the studs of an interior wall. It cracked some studs, and ripped studs out of that wall at the top plate. Glad it wasn't my house.

[mark mcfarlane]

Yep.
You should see what a 425 gallon fish tank can do to a wall, when it's weight is only carried by the studs of an interior wall. It cracked some studs, and ripped studs out of that wall at the top plate. Glad it wasn't my house.

Wow, That's 3550 pounds for the water alone, then probably ~1000 lbs for the tank and substrate (rock). That's the same weight as my pickup truck.

[rudy de haas]

Walls are 1/2 inch of very old plaster over what I believe to be two deep brickwork followed by cavity followed by exterior portland stone (it's a strange old house). To be honest this is sounding like such a bigger job than I imagined that I just need to accept that I should make my life easier, move the lounge around, and plop a couple of floor mounted stock shelving units in. There is a tonne more stuff we need to get sorted, including attaching a climbing wall to one of the kids bedroom walls (that is a nice simple stud wall) that I think I should just pick a different fight, if you know what I mean.

As usual " it depends" on ...

If you have room and the existing wall is not sacred:

1 - tear out the plaster wall (or just cut a groove into it where the shelf and fasteners go)

2 - build a new wall about X inches out from the old one where x = about 1/3rd of the intended shelf depth

3 - cantilever the shelf into the new wall using it to fasten the wall itself to the brick using small angle brackets above abnd below (but remember pressure is mostly upwards, not downwards, the weight goes on your fake wall)

Choose a wood that doesn't like to split lengthwise (e.g. jatoba) or, if you want a color like hickory, check for cross grain in the way it was cut.

With this approach you get a new feature wall, noise/vapor insulation, and a thin shelf you can do chin ups on if you want to.