Another option, is to thoroughly coat with a product called "Liquid Roof". It can go over the dicor. This stuff is pretty awesome. Our dealer coats every seam with this stuff on the new units. We've had it on 2 of our RV's, and it held up very well. If you follow the instructions, it works very well and does not act like the dicor will. A little pricey, but works.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.