Great bunk bed and easy to put together. I did it all myself I just needed help by my husband putting the the top bunk on. It says top bunk hold 400 lbs but I don't know. I'm 185 and my son is 50lbs and it felt slightly wobbly when I laid up there and yes I did tightening everything tight. I do however highly recommend this bed for kids and teenagers. My son is in love with his new bed. Customer service is always so helpful too when needed!! I'm a loyal wayfair shopper. Also the twin top mattress I already had was 9 inches it fits and still is low enough for the railing to keep someone from falling off.