A lot of RV’s, Travel Trailers or even Motorhomes use commercial roofing materials such as EPDM’s, TPO’s and PVC’s during manufacturing. TPO’s can be resealed with the same heating tool they use to install the roof. For EPDM, you can use EPDM cover tape, butyl seam tape or better yet, Eternabond® to seal rips and tears. When using seam tapes, the manufacturer usually recommends installing it on center. This is true for static roofs, not for RV’s that create their own 70mph wind driven rain. Personally, I’ve had greater success installing it slighly off center. On a 6″ wide tape, use 60% of the width of the tape towards the front, 40% towards the back. You need more tape surface area at the leading edge.