my 11 yr old put it together.  easy and sturdy.  it is on the heavy side but good for stability, bad for me moving it a lot from the back door!  I broke off the bottom ramp but kitties jump up anyway.  they love the height and i put it up against an extra back screen door so they feel like they are outside.  also, lots of scratching posts on it they love.  overall, still very happy with it a year later!