Hi Vanleigh Owners
Going to have to do some maintenance to the roof on a 2020 39FBB and does anyone know what silicone caulk Vanleigh uses where the gutters are attached to side and over the top and side rubber slide seals, I was reading that a lot of silicones are not compatible with each other.
Thanks spud706
Vanleigh used Dicor membranes until 21 models where they switched to Alpha systems. At the plant they would use the same brand roof sealants as the membrane (as required from the membrane manufacturer).
I have a 21 and an Alpha roof and have used only Alpha sealants on my roof although my membrane warranty is void due to solar install. I have seen posts where dicor on Alpha has caused the membrane to bubble up. I saw you stated you had a 20 so likely have a dicor roof but for others if you have Alphas care instructions here:
I have a 2020 39FBB as well with a Dicor roof membrane. I use the Dicor self leveling Lap sealant 501LSW-1. I recently had to replace the roof vent fans due to a hail storm and used about 3 tubes. Got a 4 pack from Amazon for less than $40.
If sealing a vertical surface be sure to use the non self leveling sealant Dicor 551LSW-1 so it doesn’t run down the side. 
Thankyou for the information, now I know where to start. Hi Stuart sorry to hear about your hail storm must have been really bad having to replace the whole unit instead of just the clear vent cover did it do any damage to your roof membrane ?
Hey Spud,
It didn’t damage the roof membrane or the solar panels luckily, but did shatter two of the three vent fan lids and the shower skylight. That hail also did about $12K in damage to my truck too, so that made for a fun experience.
Even just replacing the vent fan lids, it still required removing the old sealant and applying new. It was a challenge just trying to find replacement lids too, but strangely found them in stock at Home Depot.
I’m also planning this year to reseal the entire roof since we’re at 4 years old now. I’ll be using the same Dicor products to accomplish that.
Really sorry to hear of all the problems that Stuart had with hail. Another question I have come across is when recaulking your roof, will you take all the old caulk off or just put new over the top of the old caulk, looking online I have found that it seems to be around a 50/50 choice
Thanks Spud. One of the hazards of living in Colorado is the hail, wind, snow and tornadoes. That hail storm also shredded the three slide toppers, but they were starting to tear away from the sides already. Replacement was pretty easy and I have upgraded the slide toppers with stronger material from Tough Top awnings.
Example of the hail damage to the slide toppers
Regarding whether to remove the existing sealant or not, I’ve heard the same 50/50 opinion. I did remove the old sealant when replacing the vent covers and skylight as that is the only way to get to the screws. I didn’t remove the existing sealant when I resealed a few spots along the front & rear caps. When I reseal the whole roof, I’ll probably just go over the existing sealant. Removing the old sealant can be quite difficult even in warmer temperatures and you run the risk of damaging the roof membrane if not careful.
Another option I’m considering for resealing is using Eternabond tape instead of the Dicor sealant. It looks like it would be a bit easier and provide a good seal along the sides, from and rear. (And probably not as messy LOL) I found this video about that option I Stopped Resealing My RV Roof & Did This Instead. He also has posted additional videos on how things have held up at the one and two year mark.
Hi Stuart, I have also been looking into Eternabond videos, I had to use some on a mishap with a low hanging tree branch, thankfully did not tear membrane just scuffed it but I decided to strengthen it up a bit by covering with Eternabond, and that has lasted over a year without any sign of failure. It might be the easiest way to go, the only thing is what happens if you have to replace say like your vents, can you get the tape back off ???
Hi Spud, the tape can be removed, but it takes some time and determination (which is a good thing IMO). In one of the followup videos from the link I posted he talks about removing the tape if needed. I think they advise using a heat gun and carefully pulling it up, there’s also some adhesive treatment that is available from Eternabond to help remove and clean up the residue.
I’ll definitely be using the tape to seal both sides of the roof and the seam for the front and rear caps. Still thinking about using the tape over the roof penetrations (vent fans, skylight, etc), but I do like that the tape would add an additional layer of protection and remove the need to reapply sealant to those items. Not sure if I want to make it more difficult to remove those vent fan covers if I have another hail event LOL.
Hey Stuart, Thanks for all the info, will definitely think more about the tape.