Removing caulk from roof
#1
Hello, forum.

I'm in the process (literally - I just climbed off the roof to post this) of replacing my vent caps. I used mineral spirits (moistened rag) to remove the old caulk/putty, but it left a "sticky" feel, so I Googled and found that you're not supposed to use it on EPDM. Other references said acetone was OK, so I wiped the area and it removed the effect of the mineral spirits.

Questions - 1) have I done any damage to the roof, 2) is there something more I can/should do to mitigate the effect of the mineral spirits/acetone and 3) in the future, what's the best solvent to remove old bonding agents?

Thanks!

Nick 
2010 EC850
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#2
This issue came up once before on the old forum.  As I recall the mineral spirits caused the roof material to swell in "bubble" like spots.  Nothing was done and the roof material returned to normal on it's own.  I'd recommend leaving it alone for a day or two and see if it returns to normal.

Maybe someone else will have better information than that.  I imagine that you're in a bit of fluster at the moment and thought I'd chip in my 2 cents.
testdog is the normal user name for admin-rich - it lets me see the forum without the clutter of admin tools.
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#3
Hi testdog. Thanks for the quick reply. There was no bubbling or other deformation - just a feeling of residue, which the acetone removed. I'll wipe it with denatured alcohol and proceed, although I would like to hear what others use in similar situations.

Also, any idea why Dicor develops balloons over the screw heads? Some of the slight mounds over the screws from the original installation have become inflated with air. 

Thanks,
Nick
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#4
(06-24-2018, 12:53 PM)nick_m Wrote: “Hello, forum.

I'm in the process (literally - I just climbed off the roof to post this) of replacing my vent caps. I used mineral spirits (moistened rag) to remove the old caulk/putty, but it left a "sticky" feel, so I Googled and found that you're not supposed to use it on EPDM. Other references said acetone was OK, so I wiped the area and it removed the effect of the mineral spirits.

Questions - 1) have I done any damage to the roof, 2) is there something more I can/should do to mitigate the effect of the mineral spirits/acetone and 3) in the future, what's the best solvent to remove old bonding agents?”

Thanks!

Nick 
2010 EC850

Hi Nick, I doubt that your 2010 EC has EPDM roofing (meaning, rubber roofing)...As far as I know EC only used TPO (thermopolyolifin) sheet roofing (vinyl like), and mineral spirits will not damage your roof, but it will damage EPMD.... I haven’t tried acetone on my TPO, so I can’t comment on it’s affect, but acetone is very strong, so should first be tested in an inconspicious area before applying...

As far as the Dicor goes, they use ‘self-leveling’ type Dicor on the roof, and over a time it does tend to bubble a bit, but it otherwise works well, so I just check it say once a year or so and occasionally apply another top coat where needed.... You should pay ‘special attention’ to the seams over the front and rear FG caps, because a leak there can be a near disaster as the (otherwise enclosed) front cap has the potential to then accumulate a fair amount of damaging water...For the same reason, the side cap seams are also just as critical...

3 tons
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#5
Thanks, 3 tons.

Not sure why I assumed it was EPDM... good to know I didn't damage it. I ended up using soapy water, rinse, and wipe with denatured alcohol. That seemed to be an even better cleaning solution than mineral spirits.

This is my first experience with the Dicor - I like the way it levels out, and I particularly like that you can use it as a "touch up" sealer.

Any thoughts on Eternabond tape? I've been thinking if using that for the front/rear cap seams, but I don't like the dark bonding substrate, which is visible along the edges. Dicor can be a bit messy, but I like the smooth, white finish. However, if Eternabond really is a single time application, I could live with the appearance.


Regards,
Nick
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#6
Well I proactively put Eternabond over both critical front and rear cap seams (in east and west direction), atop the caulk, mostly as a redundant ‘second seal’ approach...The surface should first be cleaned with alcohol else the tape can lift... Again, its best not to caulk and forget...JMHO
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#7
3 tons,

How long would you wait to put Eternabond over the Dicor? is 48 hours enough (80% cure) or would you wait 30 days (for 100% cure)? 

I started to remove the Dicor on the front cap seal before realizing that you can patch it, rather than replace it. I think I'll simply re-caulk the portion I removed and then cover it with Eternabond later this fall.
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#8
(06-25-2018, 04:58 PM)nick_m Wrote: 3 tons,

How long would you wait to put Eternabond over the Dicor? is 48 hours enough (80% cure) or would you wait 30 days (for 100% cure)? 

I started to remove the Dicor on the front cap seal before realizing that you can patch it, rather than replace it. I think I'll simply re-caulk the portion I removed and then cover it with Eternabond later this fall.

Admittedly I’m no expert in this matter, but I would think a full cure (or near so) makes sense...I believe that once the eternabond is in place, it effectively becomes the de facto primary seal, leaving the factory seal as a very robust secondary...Eternabond edges should also be periodically inspected for possible lifting...If lifting occurs, don’t hesitate to caulk the edges...JMO

3 tons
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#9
I redid my whole roof myself.  I went on-line for recommendations and followed suggestions and it worked out perfect for this 'ol gal.  I was informed  in my documentation that I did have EPDM, so I treated the roof as such.  Cleaned it with OXY, Dish Soap and a bit of TSP in bad areas and it came out shining.  I taped everything before re-sealing as my unit is a 2004 and was not maintained.  She had a soft spot above the ladder, so I took special care of this area and avoid it.  Apart from replacing the bathroom dome skylight, it's all good to go.
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