I have concrete ceilings in my 10ft ceiling condo.  I bought these because I can’t drill into the ceiling.  Because I’m on the upper end of the high limit for this item, they are wobbly and I don’t feel 100% confident they won’t fall in the future, especially with popcorn ceilings where You are trying to create tension against an uneven surface.   Not recommended for a child’s room. They were tricky to install but we did it another way than the instructions and it worked well.  A piece was broken and umbra customer service did a great job of quickly replacing it.  They do hold very heavy wool, thermal blackout curtains however!