RV Do-it-yourselfers use butyl and putty tapes to seal the underside of flanges on roof vents, windows, drip caps, etc. -- any application where a metal or plastic flange of a component is being screwed down onto a roof or sidewall on your motorhome or travel trailer.


Putty Tape


Putty tape is pretty much what it sounds like it would be, simply putty formed in a rolled "tape" configuration. It is a sticky material used on surfaces between windows and sidewalls, roof vents and roofs, and anywhere else where a seal tape moisture gasket is required to seal out the water. Any time you install trim metal, a new roof access ladder, and just about anywhere else you will penetrate the outside surface of your rig, you will need this gunk on a roll.


The disadvantage of using putty tape in an RV application is that it dries out more quickly than butyl tape. Also, the putty tape is not recommended for sealing components to an RV EPDM rubber roof. Therefore, most RV repair professionals use butyl tape as opposed to putty tape for better results long term.


Butyl Tape


Butyl Tape

Butyl rubber tape costs more (nearly twice as much) than butyl tape and is more difficult to work with, but it does not dry out as quickly. While you can use putty tape on sidewalls, you should use butyl tape exclusively on an EPDM rubber roof. This is because the putty tape is made from petroleum and will leach petroleum products onto the EPDM rubber membrane, potentially damaging it.


Butyl tape is made synthetically and is solvent-based, so it will not emit the same harmful chemicals onto your roof. Also, butyl tapes are less sensitive to a loss of effectiveness due to high heat, like you would find on a roof exposed to the sun and its UV rays.


Butyl tapes also remain more flexible when it is cold and more stable when it gets hot than natural rubber seal tape like putty tape. Butyl tapes are very durable and flex well with the movement of the coach when you are traveling down the road. This maintains an airtight bond between components and the RV.


Butyl tape has excellent adhesion as well, so much so that the tape roll comes with a paper liner so that the layers of the roll do not bond to each other.

What Are the Advantages of Butyl Tapes?

Advantages:

  • A strong initial tack— has a more aggressive hold on contact than acrylic adhesives
  • Has a high level of adhesion because it bonds to a huge variety of surfaces
  • Air impermeable
  • The high degree of waterproofness, ideal for RV uses

Disadvantages:

  • More expensive than Putty Tape
  • Does not hold up over time to direct exposure to UV light or chemicals
  • Susceptible to oxidation and may darken or discolor

Neither of the final two disadvantages is generally an issue when using butyl tape for RV applications. In most cases, the butyl tape installation is covered with another sealant on the top of the installed flange or frame.


RV Part Shop Sealing Tapes and Sealants


We carry all the types of butyl and putty tapes required by RV owners in a variety of lengths, thicknesses, and colors. We also carry Dicor lap sealant for application over installed items on your RV roof, as well as ProFlex sealant, recommended for vertical surfaces like window or door installations.