Thanks for posting these images Allison, it helps to see what you are working with. It is very likely that these are installed for window washing work, or servicing purposes. It is likely that anything you hang from here that appears permanent might draw attention and you may get asked to remove it. The other piece is, it might impede window washing or mechanical services of the building at some point, and then you would be asked to remove it.
BUT, if you are willing to take the risk and just put something up and see how it goes here are a few ides. The size of the hooks and the way they are mounted suggests they would hold a lot of weight, so I wouldn't worry too much about them falling out. The spot would likely receive a lot of wind and movement, so I would not use anything that would wear through, like a rope or a wire. The wind exposure would also mean I would want to mount the trellis on a supportive frame, as trellis is usually assembled pretty loosely and meant to be mounted somewhere.
I am assuming you are referring to this type of trellis/lattice -
After you decide the size of the trellis you want, you would then build frame that size with either 2x2 lumber or 2x4 lumber. 2x2 lumber is likely sufficient, but can be a little brittle to work with so you may need to pre drill holes before you screw anything to ensure it doesn't crack. .
I would cut four pieces of this (top bottom and two sides) - (make sure the wood you buy is pressure treated or cedar so it can stand up to the elements)
At this point, when the frame is built you want to fasten the trellis to the frame. I would do this using screws and washers like this (a staple gun may also work for this, but staples may not drive through the trellis well) These screws would also work well for attaching the corner braces listed above. Make sure the washers are the right size for the screws you buy-
And then use a link like this to join each eyebolt to the ceiling brackets. Make sure the one you get is large enough for the eyebolt and the ceiling bracket to work with it.-
The trellis will blow around and move a bit, so you will need a way to secure it from doing this. Rope at the bottom might be sufficient for this, since it would not be load bearing and just to control the sway. Tying it at the bottom to the balcony wall supports, a planter, or sand bags might work, depending on your set up.
If you want to move away from using the upper ceiling mounts, you can also build a similar thing and zip tie it to the balcony wall posts like this I have had some success with this in the past -
Hey Alison, it would help me to answer the question if you could post a few photos of the holes you are talking about, both close up and far away, and I can give you a sense of hardware you might need for this. There is an add image option in the replies area, it should be easy to add an image or two here.
Thanks for posting these images Allison, it helps to see what you are working with. It is very likely that these are installed for window washing work, or servicing purposes. It is likely that anything you hang from here that appears permanent might draw attention and you may get asked to remove it. The other piece is, it might impede window washing or mechanical services of the building at some point, and then you would be asked to remove it.
BUT, if you are willing to take the risk and just put something up and see how it goes here are a few ides. The size of the hooks and the way they are mounted suggests they would hold a lot of weight, so I wouldn't worry too much about them falling out. The spot would likely receive a lot of wind and movement, so I would not use anything that would wear through, like a rope or a wire. The wind exposure would also mean I would want to mount the trellis on a supportive frame, as trellis is usually assembled pretty loosely and meant to be mounted somewhere.
I am assuming you are referring to this type of trellis/lattice -
https://www.homedepot.ca/product/orosz-outdoors-cedar-ladder-trellis/1000104880
https://www.homedepot.ca/product/suntrellis-1-ft-x8-ft-privacy-plus-brown-lattice-panel/1000804090
After you decide the size of the trellis you want, you would then build frame that size with either 2x2 lumber or 2x4 lumber. 2x2 lumber is likely sufficient, but can be a little brittle to work with so you may need to pre drill holes before you screw anything to ensure it doesn't crack. .
I would cut four pieces of this (top bottom and two sides) - (make sure the wood you buy is pressure treated or cedar so it can stand up to the elements)
https://www.homedepot.ca/product/micropro-sienna-2-x-2-x-8-treated-wood/1000791632
Assemble them using corner braces on the inside of the frame like this -
https://www.homedepot.ca/product/everbilt-6-inch-corner-brace-in-black-1pc/1001183195
After the frame is built I would install two eyebolts on the top like this -
https://www.homedepot.ca/product/everbilt-5-16-inch-x3-1-4-inch-zinc-eye-bolt/1000769941
At this point, when the frame is built you want to fasten the trellis to the frame. I would do this using screws and washers like this (a staple gun may also work for this, but staples may not drive through the trellis well) These screws would also work well for attaching the corner braces listed above. Make sure the washers are the right size for the screws you buy-
https://www.homedepot.ca/product/paulin--8-x-1-1-4-inch-square-drive-flat-head-deck-screw-unc-in-green-100pcs/1000156101
https://www.homedepot.ca/product/paulin-1-2-inch-fender-washers-zinc-plated/1000141102
And then use a link like this to join each eyebolt to the ceiling brackets. Make sure the one you get is large enough for the eyebolt and the ceiling bracket to work with it.-
https://www.homedepot.ca/product/everbilt-5-16-inch-stainless-quick-link/1001027125
The trellis will blow around and move a bit, so you will need a way to secure it from doing this. Rope at the bottom might be sufficient for this, since it would not be load bearing and just to control the sway. Tying it at the bottom to the balcony wall supports, a planter, or sand bags might work, depending on your set up.
If you want to move away from using the upper ceiling mounts, you can also build a similar thing and zip tie it to the balcony wall posts like this I have had some success with this in the past -
https://www.homedepot.ca/product/gardner-bender-14-inch-xtreme-cable-tie-blk-100-bag/1001014217
Hope this helps you think it through a little!
Hey Alison, it would help me to answer the question if you could post a few photos of the holes you are talking about, both close up and far away, and I can give you a sense of hardware you might need for this. There is an add image option in the replies area, it should be easy to add an image or two here.