You should also treat your rubber roof with a UV blocker that will aid in reducing the dreaded black streak/white chalking problems that occur with roofs that are not maintained properly.
Any re-sealing required on a EPDM rubber roof can only be accomplished with an approved EPDM sealant. These are available in either a self-leveling form (only use on flat surfaces), or non-leveling form made by "Dicor." Do not use silicone or any other sealants not designed for EPDM. They will not adhere.
There are a couple of complete roof coatings available for EPDM roofing, but in my past experience, I felt they did not perform well, or accomplish the results the customer was expecting.
Remember, all sealants are only as good as what are under them. A rule of thumb is two applications, and then it usually becomes necessary to remove prior caulking and start over with the correct type of sealant for your camper’s roof.
In the RV industry roofs are a big problem. There are many different substances used to make RV roofs. The most common is EPDM or rubber. Then you have TPOs, fiberglass, Filon and aluminum. All the different types have pros and cons. The one thing they all have in common is they have openings in them that are caulked. Most leaks occur at a caulking joint.
If your roof has leaked for a while, the wood under the rubber might be weak and thus, unable to hold the termination bar molding securely to the roof. No amount of caulking will hold this molding down.
New RVs & Motorhomes with slide-out rooms, these movable rooms are notorious for leaks. Most of the leaks located in slide-out rooms happen in two locations. The first is at the outside corners of the leading edge where the rubber roof folds down over the side and up the front, which creates an opening right at the outside corner.
Look at this location first for all possible slide-out room leaks as water will travel and show up nowhere near the actual leak. The other popular location is at the lower outside corner closest to the RV. To access this location, look behind the rubber wiper seal. This location can, and should, be caulked with silicone.
Take your time looking for leak locations. The slightest crack will allow water to penetrate and, if the location has been repaired once before, remove old material before applying new sealant.