Can I use weed to cover grass to make play area

Hi, Please excuse my complete lack of gardening knowledge! I would like to extend an area that I have bark in at the bottom of my garden. This area was never turfed and up until recently had a tree (that had died) planted in it. I wold lien to extend the barked area into the lawned area to create a play zone for the trampoline (which ruins the grass!) and the climbing frame (which also ruins the grass!) So, can I cover the grass with a weed fabric at all? Or do I need to get he grass up? And secondly,I'm considering some bamboo to section the area off - is it ok to plant it inside tubs as I've been led to believe it can spread and become out of control?! Many thanks in advance ????