Can you seal over old RV roof sealant?

Can you seal over old RV roof sealant?

By Chris Dougherty

Chris Dougherty is a certified RV technician. Here is a letter he received from a reader while he was serving as’s technical editor.

Dear Chris,
When inspecting the roof on my Rockwood travel trailer I have noticed some areas of sealant that cause some slight concern, such as cracking. Am I able to apply new sealant over the old or does the old sealant need to be removed first. —Charlie

Dear Charlie,
Yes, you can absolutely put sealant over old IF:
•The sealant on the roof is solid, not peeling up, and is affixed to the roof. Try picking at it. If it peels up, or you see signs of dirt under the sealant, then it should be removed and replaced. If its hard to remove, leave it in place and seal over it.
•The roof and sealant are clean. Cleaning the old sealant first is essential. Clean the area with an RV roof cleaner, and follow up with a good rinse with a wet sponge, then once dry, clean the area with a rag soaked with denatured alcohol.
•A couple of other points. First, use the right type of sealant. Some TPO roofs won’t react well to common lap sealants on the market, so be sure to use the product recommended for the particular roof material you have on your roof. If you’re not sure, you can contact your RV’s manufacturer, although your owner’s packet should have the information you need.

Second, be sure to use self-leveling on the horizontal fixtures on your roof, but the edge seams should get non self-leveling sealant. Third never use silicone sealant on an RV roof or any of the fixtures. Silicone is incompatible with RV roof sealants, and if it has to be replaced, the new sealant won’t stick to it.

Editor’s note: RV roof cleaners and sealants are available at




2 thoughts on “Can you seal over old RV roof sealant?

  1. Carol Erlingheuser

    I too enjoy reading cemetery headstones. Growing up in a town founded in 1639, I saw many stones that were carved with death’s head angel-like figures.
    That final quote you included has always given me the shivers.

    1. paul Grens

      We are from the Midwest and don’t see the heads here.
      But we did see a lot in the old Boston cemeteries.
      I have a couple from a old prison cemetery in Boise Idaho;
      “Here lies Lester Moore shot dead by a guard with a 44.
      Now there is no Les no more..”

      “I told them I was sick!!”

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