Petunia, I found my bath mat gets unglued from the shower floor when things get dryer (no one's showered in a bit) and then I turn on the water again. I have gone "surfing" on the bathmat and wrenched my back not falling. I have a shower like yours. So, I discovered the "problem" and even told my husband about it to warn him but have I replaced the bathmat yet? No :-)