shelving
I'm looking to use the "twin slot" uprights and brackets for wall mounting a shelf to use as a work surface for laptop, printer, working on admin etc.
For strength is there any advantage in using longer uprights (down to floor level) when the lowest shelf will be about 4' from the floor? To distribute the weight – or does it not matter?
It would be on a "party" wall, brick with plaster.
Do you need more shelves, or do you just need one of the existing shelves to be at a different height?
If it's the latter, it may be easier for you to add some supports underneath one of the existing shelves like this:
The supports should run the depth of the cabinet, and you can attach them with command strips or double-sided tape. Be careful removing them because shelves are often covered with paper that's printed to look like wood.
If you need more shelves, it may be better for you to build a new shelf using the same idea, but have the new shelf resting on one of the existing ones. You'd lose a little bit of space on the lower shelf, but you'd avoid the risk of breaking your rental agreement and/or losing your deposit. You'd also need to be careful not to overload the lower shelf or the whole thing could come down.
If your brick is solid and does not seem to be crumbly (like in +100 year old house) then I would always suggest and even my self use and Anchor bolt - In some countries called a robolt - These are on of the best load and pull rated bolts. And I always try to use these bolts because you can never be sure about who will put what on a shelf. Using these bolts if installed correctly(not difficult) are rock solid.
All you have to do is:
And because this is for your home and not a building site you would finish it off with a bolt "nut" cover. This will give you some extra points with the wife for paying attention to the finer details. You can get various shapes, colours and finishes. Or just paint over them.
Using anchor bolts makes you only have to worry about the bearing load of the brackets and shelves you use. But it is obvious the shelf max load should not exceed the anchors load capacity to be safe.
I have seen shelves that collapsed because the bracket could not hold the weight but these bolts stayed put!
Disclaimer: Just a bit of humour but entirely factual.
1Monkey Test
It is a test that is taken out on shelves , hooks or other newly installed equipment that will be used to hang things off. The test is simple. Hang on the object and wiggle like a monkey. If it does not rip/pull out / bend or create damage to the area around it. It is monkey proof and guarantees to carry ridiculous load. Tested in South Africa in camping sites near nature reserves on outside fixtures
Best Answer
The concern is mostly pullout strength, and not shear. The bulk of the leverage of the shelf pulling away from the wall is above the shelf. Therefore, screws above the shelf carry most of the pullout load. It's unlikely that you will have insufficient shear strength if you use 3-4 screws per standard.
My point is that you probably won't need the standards to extend downward from the shelf, but some length upward is a good idea.