In many RVs… especially older ones… edge and corner trim is simply a thin aluminum extrusion with screw holes and a vinyl insert. In typical RV construction, siding and roof sheeting edges are simply butted together and fastened to the frame, usually just with staples. A strip of RV putty is laid over the joint and the trim is screwed on.
As time goes by, the putty gets squeezed out… the black, dirty stuff oozing around corners and window trim for example. What putty remains dries, then cracks and gaps open. Water leaks in through the edges and screw holes.
The vinyl trim insert, contrary to what people think, is not there to prevent water from entering. It’s only cosmetic to hide screws.
Chances are if it is time to re-caulk, the vinyl trim insert is also bad. Remove and throw it away. You can get new trim by the foot at a reasonable price at any good RV store.
As you remove the screws check them for corrosion. If they are corroded discard them. Replace them with the same size purchased from a home improvement store or RV shop.
Carefully pry siding away just enough to peek at the framing. Look for evidence of leaks. If you have some water damage but the wood is still mostly solid, you can get a product called “Git Rot”. It’s a liquid you mix and squirt or inject into wood. It chemically converts wood cellulose into an epoxy-like material.
If you find major damage, you can either repair it yourself or have it done at an RV repair shop. But, unless you plan on selling the RV soon you really should get it repaired.
If everything is okay, clean off the old putty. 409, Simple Green and similar cleaners work well with a non-abrasive scrubbing pad.
Tip: Regular RV putty tape is a gray material in rolls of 3/4″ or 1″ wide with a crepe-paper backing. It’s inexpensive and sold in every RV store. Far better is a “whiter” butyl putty tape that is much stickier and often has a slick, plastic paper backing. Only a little more expensive, it is far more effective and doesn’t “ooze” as bad as the putty tape.
You may want to read: Dry Rot: Spot it before it gets out of hand. at RVbasics.com
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