Does all the old butyl tape need to come off?

...and I hope it goes without saying: When you remove excess Butyl, be sure not to damage the roof material (rubber, TPO, EPDM, ...)

1.) Remove vent

2.) Scrap vent mating surfaces and roof surface clean with putty knife

3.) Clean matting surfaces with Acetone till no residual sealant residue is left (Check your roof material is safe to use Acetone on first!).

4.) Apply new Dicor gray Butyl tape (Make sure its NOT the clay tape, that stuff is trash).

5.) Use new screws to resecure vent to roof.

6.) Leave for about 24 hours for butyl tape to ooze out a little, then use a good putty knife to go snugly along the edge of the vent flange to remove the excess (I usually cut it free with the edge, then lift it off)

7.) Apply Dicor self-leveling caulk over edge of vent flange and screws, overlapping on to screws.

8.) Allow to cure for at least 48 hours in the sun.

9.) Clean mating surface on roof around where you caulked to prep for eternabond.

10.) Using the four inch wide eterna bond, start applying it so that the edge is up under the lip of the vent cover a little, firmly applying pressure, then over lap over the top of your dicor caulk then down onto cleaned roof surface.

11.) Use pressure roller tool to very firmly press roll every millimeter of eternabond tape.

These steps are optional.

12.) Get a quart can of PlastiKote or equivalent snow roof base/primer coat and a quart can of finish white Plastikote or equivalent snow roof.

13.) Go over all of the eternabond with multiple thin layered coats of the primer base coat, allowing each coat to dry inbetween. Once its built up enough layer to turn it all into a smooth coat, applying a few coats of the finish coating.

14.) Never worry about vent leaking ever again other than the lid failing.

I pressed the butyl down a little more yesterday and it rained in the night and throughout the day and were still dry. I plan on doing the hose test and if that holds should I still redo the top?

Also we had tge caps of on the front since I had to rebuild the wall from rot, and when I did we also just used butyl and had it squeeze out both sides. Should I also be removing the excess and dicor that too?

Butyl is meant to be squeezed between 2 surfaces so it oozes out some. Dicor is for top dressing. I believe.

Is butyl alright for a top layer on the seems? Wondering if I should remove the butyl on top and seal it with dicor leveling stuff? All trace of old stuff was removed. Then I put butyl underneath the vents, then on top to cover the seem and the screws. I went up top this morning and pressed the butyl a bit.

Plan on using a hose when we get to our final destantion on the room to try and find if it's sealed or not
.

Got to my campground tho at 11 to find a wet bed after all day of scrubbing and resealing ??

That can not be good. So where is the leak? Maybe not where you think it is?

AnEv942 has it on the money. Take the whole thing off when you can, and clean the butyl off with a scraper then MEK (methyl ethyl ketone). Basically the only way to be sure is to get it down to the barest possible and remove all glues and caulking. Once it's all back together with new butyl, a little eternabond on the seams isn't a bad bit of insurance, but it needs to stick to fiberglass, wood, or something other than caulks and glues.

Butyl tapeThe stuff I used I believe is butyl,same as that. When I removed the old stuff seemed like that was on theoutside of the vent. Got to my campground tho at 11 to find a wet bed after all day of scrubbing and resealing ??

sasq40 wrote:
Since I was in a hurry and my shop Got a case of butyl delivered for our shacks I ended up doing like the factory with butyl underneath and over top each screw

I think your confusing butyl tape with lap sealant. The way butyl works is it goes on first under the flange.....then as its screwed down the excess squeezes out and is easily removed with a plastic putty kknife. I always used a wooden tongue depressor with that I cut the end square with a pair of dikes.
Then a self leveling lap sealant is added over the the joint and scr heads.

My 32' trailer is 22 years old and has nothing but self leveling Dicor I've added in a few spots and replaced one skylite cover. No leaks and easy/simple maintenance