In 2008, I got tired of having my RV gutters stop up and then run over the side when an ant got caught sideways in one. I had tried some different gutter ends with drip extensions but none addressed the real problem.
The gutters are so small that they cannot handle much water, much less the constant buildup of EPDM roof cast off material, algae and other foreign stuff that seems magnetized to lodge in them. Additionally, they are not angled at any sort of useful drainage elevation so what does get into them rarely moves on out very quickly. Some awning braces actually attach over the gutters with bolts that barely clear the top of the opening and so anything that might try to go down it, like a leaf, twig or a cockroach with his hand up, will catch on the bolt and create a junk jam, again causing overflow.
On my curb side I have a huge awning with the afore mentioned mounting problem. Between the backup in the gutter at the awning attachment bracket and the normal overflow onto the awning covering shield, a great deal of the water runs off right at the edge of the rear slide seal. Over time, a lot of water manages to seep through any seal there and also trickles down and around the bottom of the slide at that place and wicks back into the edge of the flooring causing it to deflake.
Replacing the gutters is a non-option as is climbing up there every week (or less) to flush them out. After much puzzling and cursing over this, along with replacing the floor in the slideout, I decided that the solution was a lot simpler than I was trying to make it.
I figured that if I made some sort of gutter/flashing that did not try to hold the water and trash but just kept it from running on down the sides and slides, then I could direct it wherever and If it did get some trash in it, there would be no sides to it to capture it there and make a trash jam in the flow.
I started off looking for aluminum flashing that I could form but I was unhappy with the look and the work needed to get it like I wanted. Eventually, I found some DuraFlash
at Home Depot that is made of PVC and it seems to be a great solution. Being PVC, it is easy to cut, shape, glue and is virtually indestructible if struck by branches or whatever. Since there is no "edge" to actually capture the water but rather, just direct it, any trash that may get on it just washes off the side or over the end with the running water.
By cutting a piece long enough to carry gutter overflow from above the slideout to behind the rear scare light,
I managed to stop all of the dampness in the carpet and along the slideout seams. I placed it at enough of an angle to insure that the water would really rather go down it than over the edge. The slight drip lip along the outer edge keeps any water that may run over the side from running back under it and down the side of the RV. You can still see the old stains from the original gutter runoff that goes down across the scare light. Notice no stains at the end of the flashing, though.
I shaped the end of it with a little outward flare to direct the runoff away from the side of the RV
and glued it in place with standard PVC cement. Likewise, where there was runoff from the Big awning cover I put an extended piece
there to catch that and direct it back down into this new flange. I won't apologize for the current look as this was just a prototype to see if it worked, how well it worked and to see what modifications I might need to make to it to protect other places that have gutter overflow problems.
As of now, I need to go back to just make a nice looking one to replace the prototype and then make a few more to put in a few other places that have runoff/overflow problems. Just about the only changes I will make is to provide a little longer/larger flange at the ends of the awning shield to better direct really heavy flows back down the flange. At present it takes nearly a hurricane's volume of water to run over it now and even this amount does not run down the end of the slideout..
I will also add one of these across the back of the RV above the triple rear windows to keep them from collecting so much "white" runoff from the roof back there. A nice double angled pair draining to each RV corner should do the trick.