Slide out awning

Adding tension will never stop your problem. A quick way to verify this is to get on a ladder and grab the awning tube and manually twist it tighter. IF it does not get tighter doing that then adding tension will not work. Adding too much tension can affect the slide out operation going out, depending on the type slide mechanism. The problem is normal and the time the water has collected has stretched the fabric. Also, some slide covers have very little slope. Good slope and the water runs off and cannot collect. But, most motorhomes the height of the slide room to the main roof means you have very little if any slope. The best solution is to install something under the cover to shed the water. Doug