[djc1514]

Greetings,

I'm in the planning process to build some long floating shelves...about 8.5 feet long. Would like to use White Oak to match a desktop underneath, but I'm curious about the weight of the shelves and sag or worse. Can anyone advise on how I can determine how much weight these shelves can hold...including their own weight.

I would have three walls to secure them to....back wall, and two side walls, although for the depth of the shelves 8"...there doesn't appear to be any studs on the side walls.

Thanks!

 

[wallylama]

How much weight the self can hold is dependent on the shelf thickness, the type of support, and the span between supports. Have you already chosen a shelf thickness?

 

[SeniorSitizen]

Unless you actually need 1 shelf all on the same level, floating shelves could be built in random length segments to connect to 2 or 3 studs by staggering some higher and some lower to fill the horizontal space.



These pictured just slide onto a wall mounted bracket, but for weight capability they haven' been tested. For more weight a French Cleat mount may be desired but use the same staggering method.

 

[HotRodx10]

If you're concerned about the weight that they can carry, then I suspect you're thinking these will be holding books? That being the case, I would suggest pairs of shelves, a top and a bottom, with either a thick back panel (1/2" minimum) or a cleat (white oak 1x2, presumably) above or below the top shelf, that you secure to the back wall (a 3" screw at each stud) and the top shelf (2" screws about every foot for the cleat, or every 6" if using a panel). Then you have 1x6 vertical dividers, also white oak, between the shelves at the ends and a couple more at 2.5' from each end (leaving 3.5' for the center span). You'll need at least one 2" screw through the top shelf into the dividers, and 2 screws through the bottom shelf into the dividers. Assuming you're using 1x oak boards, you shouldn't have any problems with sagging.


That's just what I would do. Cleat under the shelf on the side walls, attached using hollow wall anchors, would likely be strong enough to hold it, but I'd expect it to sag some on the front edge, even with support at the back wall. You'd likely need at least one support bracket in the middle to keep the sagging small enough to not be noticeable. Even then, you might need to flip the shelf over every year or so to keep the long-term creeping sag from becoming noticeable.

 

[djc1514]

I am aiming for two shelves total that span about 105 inches in length. Was going to use 2x2's as a bracket or skeleton...more specifically...a long 2x2 screwed to each stud length wise and probably 5-7 "fingers" coming outwards including ones that run along the side walls.

Dimensions of the shelf would be 8" deep, 3" thick, and 105 inches long. I was curious about size of screws to use so HRx10, thank you. Deck screws ok, or something more substantial?

 

[djc1514]

3" thick. using 2x2's as a bracket and using 1x8's as tops and bottoms of the shelf

 

[HandyAndyInNC]

I always use pins to secure in to structure. No matter the thickness of the wood. I always set a pin in each piece of structure I can. I have stood on most of the desks and shelves I have installed. Never use something as small and that has no sheer strength as a desk screw. Use structure screws that has a high sheer strength number. The space between the pins are what matters most, then the type of wood, the thickness of the lumber. For yours, divide that by 16, and that is the number of pins you will use. You can use them on the side walls. and even the corners. There is usually great structure in the corner of a wall. I don't like using a cleat, that takes away more of the wood that performs the major amount of support. Use a pin and make it snug and as long as you can without protruding thru the front of the shelf. You can also use flat plates in an "L" instead of pins for something really large. But that is for more of the desk tops, something upwards of 1000 pounds or so. If you are not able to sit or stand on the object, then carry some weights with you. I carry about 700 pounds of weights I had created in a rectangular cube shape. They are in 50 pound increments.

 

[djc1514]

Please excuse my ignorance, what do you mean by "pins"

 

[JIMMIEM]

Greetings,

I'm in the planning process to build some long floating shelves...about 8.5 feet long. Would like to use White Oak to match a desktop underneath, but I'm curious about the weight of the shelves and sag or worse. Can anyone advise on how I can determine how much weight these shelves can hold...including their own weight.

I would have three walls to secure them to....back wall, and two side walls, although for the depth of the shelves 8"...there doesn't appear to be any studs on the side walls.

Thanks!

There is an online tool available called the Sagulator which you can use to do the calculation....You input wood species, dimensions, weight, etc and the tool will calculate the amount of sag. Just Google 'Sagulator'.

 

[djc1514]

Amazing, thanks so much

 

[HandyAndyInNC]

Pins are more like large nails with a threaded end. Bore a hole in the stud, thread in the pins, that will leave a nice smooth, shiny end that will slide into the shelf after you bore holes in the shelf where the pins are in the studs. Pins also come with a retainer that will not allow the object to be removed by pulling on it. You have to remove the retainer to remove the shelf, desk, bed or what ever object you hang. They come in many diameters and lengths. I usually use 1/2" stainless steel with 5000 pound sheer strength. For my own houses and workshops, I use either 3/4" or 1". I know what is in the walls. Old houses have a true 2" wide stud. I planned well when building the workshops for these. There are also many types of shelves that can be purchased to be used with the different sized pins. They also make large pins and attachment brackets for building a tree house. That is how I found them. I tested one in the workshop in Ca with (4) car engines sitting on it. Have never had one break or come loose. Once you see one, it will be self explanatory as to how to install them and use them. For the small 3/8" size, they will run you about $25 each.