I believe most of Grand Design units these days have an Alpha Systems Superflex TPO roof membrane. Alpha has a warranty that extends for 12 plus years. You should read the warranty found at AlphaSystemsLLC.com You will find that you could void your warranty or be denied a claim if you use other than an a Alpha product as a component this includes sealants. On their informational sites they say in bold text “ONLY ALPHA BRAND SEALANT CAN COME IN CONTACT WITH ALPHA ROOF MEMBRANE”. The other item to make note of is that the roof must be inspected at least every quarter and the inspection must be documented.