Does all the old butyl tape need to come off?
Getting ready to leave on vacation tomorrow and noticed the vent in the cabover was leaking. I stuck eternabond tape over the old butyl tape as I was advised it was alright, but it didn't stick proper...
Forum Discussion
Be careful of assuming that as sticky as EternaBond (EB) is, it is not all it is cracked up to be if installed wrong. I learned the hard way as mentioned in THIS THREAD REPLY
As shown in that link, I wrongly assumed that EB would adhere to the flange of the roof dome bubble- it did not, but it sure fastened to the existing roof!!! For EB to really seal, it needs to have a mostly flat surface and I assume it will not stick to butyl tape (BT.) If there is a "mass" of BT under EB then there might be the possibility of "fold crimps" of the EB at its edges... you do not want this. But even if the edges of the EB over BT are nice and flat, there will always be some sort of putty pocket under it.
Believe me, once EB is stuck to materials of which it is compatible, it is very, very tough to remove!!!
I will not trust EB to seal against anything but the roof itself. In the link I posted above, it was an effort to do some preventative maintenance on the roof components so as not have to continuously inspect and do surface prep and seal them. To answer your question, I would recommend taking the time to scrape away any loose material, thoroughly clean and use a decent sealer. Many folks recommend a specific RV sealant. But, I have to go through the whole process of maintenance of which I was trying to reduce with these accepted products. I am now using THIS PRODUCT.
If the vent is needing most or all of the surface sealant removed then perhaps re-butyl'ing might be appropriate. I ended up doing just that for my recent repair to correct the botched job in the first link above. EternaBond it almost nearly impssible to remove without a LOT of work. I did it as well as installing a new roof item with new butyl tape and then sealing properly over the whole assembly. See the results here:
Repaired the roof, replaced the bubble dome...
In that repair thread, you can see the old bubble and crank-up vent; the after images show the proper repair job as well as new sealant over the vent. The vent seal was maintained per the procedure I described.
I do not knwo what the OP's exact situation is, but from the little description Me believes that there is some significant work in the future to correct the EternaBond band-aid.
As shown in that link, I wrongly assumed that EB would adhere to the flange of the roof dome bubble- it did not, but it sure fastened to the existing roof!!! For EB to really seal, it needs to have a mostly flat surface and I assume it will not stick to butyl tape (BT.) If there is a "mass" of BT under EB then there might be the possibility of "fold crimps" of the EB at its edges... you do not want this. But even if the edges of the EB over BT are nice and flat, there will always be some sort of putty pocket under it.
Believe me, once EB is stuck to materials of which it is compatible, it is very, very tough to remove!!!
sasq40 wrote:
What's the proper process to reseal the roof vents.
Remove most the butyl then re butyl? Remove the vents completely, or what?
I will not trust EB to seal against anything but the roof itself. In the link I posted above, it was an effort to do some preventative maintenance on the roof components so as not have to continuously inspect and do surface prep and seal them. To answer your question, I would recommend taking the time to scrape away any loose material, thoroughly clean and use a decent sealer. Many folks recommend a specific RV sealant. But, I have to go through the whole process of maintenance of which I was trying to reduce with these accepted products. I am now using THIS PRODUCT.
If the vent is needing most or all of the surface sealant removed then perhaps re-butyl'ing might be appropriate. I ended up doing just that for my recent repair to correct the botched job in the first link above. EternaBond it almost nearly impssible to remove without a LOT of work. I did it as well as installing a new roof item with new butyl tape and then sealing properly over the whole assembly. See the results here:
Repaired the roof, replaced the bubble dome...
In that repair thread, you can see the old bubble and crank-up vent; the after images show the proper repair job as well as new sealant over the vent. The vent seal was maintained per the procedure I described.
I do not knwo what the OP's exact situation is, but from the little description Me believes that there is some significant work in the future to correct the EternaBond band-aid.
