What is the usual maximum load for drywall?
You will NOT want to support your 78 1/2 inch rod from the drywall alone. Drywall fastened up to the ceiling is a pretty good challenge just holding up it’s own weight then yet you trying to add 70 pounds to that.
So what you want to do is to locate the support members (usually called ceiling joists) to which the drywall is attached. You would then want to use screws that penetrate through the drywall and and up into the support member to hold up the brackets for your rod. For most ceiling supports the members will be found to be 16 or 24 inches apart so you should be able to find 5 or more support points for the rod if it is running across the direction of the support members. If the rod is running in the same direction as a ceiling support member then you would attach the rod support brackets at 4 to 6 locations along the same support member. In this latter case it means that you cannot locate your bar just any old place but directly under a ceiling support member.
Finding where the ceiling joists are located can be done with a stud finder tool. A simpler scheme is to get a strong magnet and scan it across the ceiling looking to find the steel nails or screws that are holding up the drywall. Each located screw will be at a point just under a support member. Find multiple points and a ceiling joist map can be created.
If the bar that holds up the ball chain partition is an extruded metal track then the mounting technique will likely not involve any brackets but instead involve drilling holes through the metal track at the correct points where screws can then be run up through the track into the support members in the ceiling.
The answer depends in part of the drywall. 1/2 drywall doesn’t have the same strength a 5/8 inch, and both are common. High impact or abuse resistant drywall is stronger than type X or regular rock. Typical, the plastic coil type anchor has about 30 lbs. pullout, 50 lbs. shear in 5/8 drywall if the it is screwed in tightly and the pilot hole isn’t oversized (the instructions should give the recommended starter hole size, about 1/4 inch for most), the toggle type, with an expanding wing, will give up to 200 lbs pullout strength, shear is actually slightly less, since it can rip the drywall when sideways pressure is applied.
Most drywall anchors work better with framing on 16 inch centers or less, and the drywall must be in good condition, something you cannot always determine when working in an existing wall assembly. For very heavy loads, you will always be better off aligning the mounting holes with framing members (studs or joists) and screwing through the drywall into the framing behind it. This will eliminate the need for any anchors at all. Things like television brackets, large mirrors, shelves, and upper cabinets have a known weight, but can be overloaded when the shelves are stacked full, or that bigger plasma TV is on sale during the holidays.
Try to avoid placing drywall anchors too close together, if you use them, and avoid placing them in a straight line, if possible, since this creates a situation where the anchors may actually work with each other to weaken the drywall.
These types of anchors are the most common, and when you think of drywall anchors, you probably think of these. They’re small little plastic anchors that are fairly basic, and you’ll see them included in most shelf kits that you can buy at the store.
They’re called expansion anchors because when you drive in the a screw, they expand and push against the drywall in order to bite into it. They’re not the best type to use, since they’re not able to hold a whole lot of weight (maybe 10 to 20 pounds at most), but they’re grea…
How much weight can drywall hold? It depends on the drywall, and how you fasten to it, as well as how the drywall itself is fastened to the framing underneath it. Oh, and for those who say “None”, or that “items must be fastened through the drywall into the stud”? We commonly hand electrical panel boxes weight 60 pounds or more to drywall with toggle bolts, but not on your typical 1/2 inch thick residential drywall. When you move up to 5/8 inch fiber reinforced drywall (Type X is standard for most commercial applications), a 1/4 toggle bolt inserted correctly is rated for 380 pounds shear l…
Drywalls / plasterboards are very porous materials. This means that you can’t hang / attach anything heavy on the wall with only a screw or nail if you won’t find a stud.
With that said, you need a drywall / plasterboard anchor that distribute the weight on a larger area behind the wall.
The best product to use when hanging heavy items on a plasterboard / drywall is the Duck foot plasterboard anchor. It works for all kinds of plasterboards / drywalls, so you don’t need to know the thickness of your wall and the Duck foot anchor is super easy to install (you don’t need any special tools to install it). Each Duck foot anchor holds up to 50 kg (110 pounds) in shear load, so if you install 6 anchors in the wall to distribute the weight, it holds up to 300 kg (661 pounds).
This is a link to the duckfoot website for more information:
A heavy mirror always needs support if it’s to be installed on drywall.
Provided the mirror has a frame, I like to use “french cleats” if I’m installing a heavy one on a wall.
Installed correctly between two studs,your mirror will not fall down.
You can also buy metal cabinet hanger rails which work in the same way. They are a little lower profile than a french cleat. One rail is installed upside down on the back of the mirror,the other is installed between two studs the other way around.The two rails lock together and make an extremely solid mount for heavy items like a large mirror.
In the UK…
How much weight a drywall screw will vary based on a number of different factors including the size and design of the screw and the materials used to make it. These can vary by manufacturer. The type of wood and the type of load are also a factor.
It’s possible the manufacturer or your screws has released technical information about the screws you plan to use. Here’s an example http://www.trianglefastener.com/pdf/drywall.pdf
Drywall screws are generally not recommended to hold weight such as to hang things off of. They’re called drywall screws not hanging-off-of screws. They have a thinner shaft and are more brittle than other types of screws.
How much weight can you mount to a wall?
I’ve only recently moved beyond yellow wall plugs and into a different style of self taping plug that’s rated to significantly higher weights. These plugs advertise 80 lbs of pull out / 120 lbs of down ward pull through.
What kind of weight can the dry wall withstand before it fails? I’m looking at regular household application, so standard width sheets apply (since I’m sure the width will affect this answer).
I sort of wondered this on the metal, butterfly style plugs but at least they seemed to distribute the load on a larger section of the drywall.
In response to some of the questions, assume 16″ on center, say 1/2″ or 5/8″ sheets. My specific application is hanging shelving (screw down strip/track, 5 screws per strip about 12-18″ each apart, strips mounted 30″ apart, lock in 8″ hanger style arms) which I have done many times before. I’m not looking to push the envelope on how much I can get away with, I’m trying to ascertain whether the drywall would fail before the plugs would, for a better practical knowledge.
As everyone else has indicated, it is not as simple as throwing out a single weight or weight range and having it be a universal truth.
Keep in mind, the major manufacturers are constantly trying to improve their products while they trim costs of production. In a perfect scenario, you get a product that not only performs beyond your needs, but leaves some money in your pocket.
Most manufacturers will provide all the information you could want about their products. USG for example has a fantastic form that should allow you to get a good idea of what features you need to look for and what sizes of materials you should use. (This is NOT an endorsement of USG specifically. I don’t own stock, nor do I sell their product. I’m simply pointing out a decent example of the information available.)
Simplest answer in the free world: put your screws in studs whenever possible, and when you use anchors, don’t buy cheap.