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Discussion Starter · #1 ·
Hello! I have a solid concrete dome home, so the walls eventually curve up to become the roof. The exterior has been painted with at least one coat of Conflex XL before we bought the home. It now has a lot of water filled bubbles and peeling. We'd like to remove all of it and start fresh but some of it is very tight to the concrete even though other parts nearby peel off like a sheet of rubber.
What can we use to most easily remove Conflex XL Elastomeric to start fresh from bare concrete? We have tried several strippers and sanders. We find that strippers don't permeate the paint well enough and with sanders, the paint heats up, rubberizes and becomes gummy and stuck on to the house and tools.
Also we were considering using Henry 208 and 208R on different parts of the house to waterproof problem areas, should those areas be prepped down to bare concrete?

Any experienced ideas?
Thanks!! :)
 

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Not that it helps too much, but here is the data sheet for Conflex XL: http://www.paintdocs.com/webmsds/webPDF.jsp?SITEID=STORECAT&prodno=640515425&doctype=PDS&lang=E

Sanding is obviously out due to gumming, but a more serious problem is burnishing the concrete due to sanding (removing profile). You'll have a fun time getting anything to stick then.

You may try pressure washing to remove all loose pieces, and if you have some parts that are really stuck, you may be able to spot prime around them and reapply Conflex XL as a topcoat. Hey, if they are gonna stick that good - leave 'em!

SW recommends Loxon Masonry Primer (see data sheet) - is it underneath the Conflex? If not, then you need it. Did you let the concrete rest for 30 days before painting? If not, the pH will be so high (alkali) that coatings will not stick. pH can also be high just because it wants to be, so check it and primer if too high (6-12). Finally, is there more profile in the places that stick and less where it doesn't? You may need to etch the concrete to provide the necessary profile, or prime if not already done.

Wall Paint - Beauty on a Budget
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Discussion Starter · #3 ·
Thanks for that quick reply!

We bought the house 3 years ago and it was the previous owners that painted it. The house has *a lot* of problems, there are parts where water has gotten under the top coat of concrete (stucco?) so bad that it can be picked off in chunks with fingers, not many places like that, but some. However there are a lot of places where the paint can be peeled off in sheets, or bubbled enough to pick off. These parts do seem to be on the parts of the house that are made of the on-site mixed concrete (compared to the kit included slabs) so it may have to do with their preparation. I didn't mention above but yeah, we also tried pressure washing which will get some parts off but mostly it ends up leaving a bunch of tiny peel-ups, hard to explain.

So my worry about just painting over what *seems* to be sticking on tight is that their earlier coatings may bubble and peel below whatever we paint over it. We don't know what kind of prep they did to the concrete and we only know it's the Conflex because they left the remainder bucket for touch-ups.

I posted over on the roof section too... for much of the house we're just throwing up our hands and giving up, resorting to covering a bunch of stuff up with Henry's 208 and/or 208R.
 

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This is completely a shot in the dark, but according to the Material Safety Data Sheet (MSDS), Conflex XL is very alkali (pH 9). When you power washed, did you try plain water or an acidic mixture? Maybe going 4:1 water to muriatic acid would give you an idea if acid is the key. If that doesn't work, try going alkali with TSP (trisodium phosphate) - it's sold in most hardware and paint stores.

My only concern would be that the acidic solution might corrode metal or etch the concrete. Go slowly at first, and strengthen the mixture if it works.

Wall Paint - Beauty on a Budget
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