Thread: How much weight on 1x4 shelves
8th Jun 2005, 01:14 PM #1
How much weight on 1x4 shelves
I want to know about how about how much weight can I put on the 2nd and third shelf, the bottom shelf is on the floor. I just built some shelves that are framed with 1x4 with the 1" side up. They are six feet long and two feet deep. Up rights are 1"x4"x4'. The shelves themself are made from scrap 3/4" and 1" plywood fastened with 1 1/2 and 2" power screws. The frame itself is put together with 1 3/4" power screws and "Titebond II" wood glue.
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8th Jun 2005, 03:19 PM #2
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Hard to say exactly, but here is a good formula:
"Usually 20% more than you think initially"
"If it breaks, measure the weight of gear that was on it and minus 10%"
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8th Jun 2005, 06:00 PM #3
Dont want to try and give numbers... but if you are worried about it's strength, put some more bracing on it. Looking at the unit it's fairly strong with the 1x4s on edge like that. If it did fail it would be due to 'racking', folding up like an empty cardboard box. If you put some ply or diagonal braces on the back and ends it should support twice as much.
Over engineered... possibly. Going to fall apart... Not in this lifetime
8th Jun 2005, 06:49 PM #4
It's difficult to say. If the shelves are sitting on those cross pieces and the cross pieces are glued and screwed butt joints then the strength is going to be in the glue and screws and not in the timber.
It wouldn't take much to put an upright in the middle to give it some extra support.
8th Jun 2005, 06:51 PM #5
9th Jun 2005, 01:37 AM #6
If you have the time and inclination, go to the Forest Products Laboratory and then look up the Wood Handbook to get specs for various timbers and composites. You will need both time and to have your calculator handy, but I don't think there is an easy answer to your question. It not only depends on the construction, but the duration and placement of the load. For instance, the weight that a given shelf will hold will reduce over time if there is a continual load above a certain level placed on it. The weight that a shelf of a given construction can hold dramatically reduces with each foot of length.
IMHO, six foot shelves need to be treated with care, but you should be able to quite easily check shelf deflection with a few test loads.
9th Jun 2005, 11:34 AM #7
Thanks all. I am going to use some extra 1x4 and put a board in the middle of each shelf running up to the shelf above it just to be on the same side. (The wife is already loading them up.):eek:
9th Jun 2005, 12:17 PM #8Originally Posted by GotCoffee66
The shelf as constructed WILL support a substantial weight, but the whole middle shelf could easily "wobble" from side to side if there is a substantial weight on it. This "wobble" will easily be compounded when additional weight is placed on the top shelf.
You would/will be amazed at just how unstable such shelves can be when heavily loaded.
You *NEED* to brace the whole structure by installing AT LEAST one diagonal brace from a bottom corner to the diagonally opposite TOP corner. (or similar diagonal bracing). In doing this you NEED to fasten the brace to the middle shelf to help make the whole structure more stable. This will addtionally provide some extra support to the middle shelf.
Alternatively you could add an additional board (vertically) at each corner, at right angles to the existing corner pieces, so that they face the front and rear. Screwing these extra boards (approx 8 screws each) to the edge of the exisiting supports will provide substantial rigidityKind Regards