The beauty of construction is that it is everchanging in technology. Having said that, the reason why the EIFS industry finds itself in this quandry is simple; too many companies are taking shortcuts and are not paying attention to detail.
The very makeup of a cinder block wall is simple; You have A. cinder blocks B. portland cement C. sand and of course D. water. The most important component is sand. Regardless if you use a leveler as Lalo puts it or a basecoat, the sand in the motar will prevent a proper bond. I know many contractors are still doing it like that today, but they are wrong. Some contractors have even gone as far as putting acrylic finish directly over a conventional stucco system. That is a nightmare waiting to happen. Those contractors who continue using archaic methods without even trying to think of a better way will hurt their customers by way of their check book and the industry by stigma. We as contractors should look at all our projects fundamentally and let common sense dictate.
Have you ever seen foundations with EIFS finish on them with evident delamination at the mortar joints, leaving a stair effect. Well that is because of the sand. Exterior Insulation and Finish System is just that. A system. By removing any integral component of the system we compromise the system.
What is wrong with an acrylic finish over a conventional stucco system?
I have never heard anybody blame anything on sand itself, maybe the quality or type of sand that is used but not sand in general. I hope that by sand you mean any loose dirt that may be on the surface of the cinderblock or leveler coat. Sand does not prevent a proper bond.
When I said a leveler coat I meant something like STO Leveler Coat (http://www.stocorp.com/webfiles.nsf/htmlmedia/fsd+244+sto+leveler+tb.pdf/$file/fsd+244+sto+leveler+tb.pdf).
Oil and water. Most people wouldn't paint over a sandy surface. Rub your finger in any mortar joint and you will see sand on your finger. If the mortar doesn't bound well to itself, than how can we expect a paint to bond to the mortar joint. Mortar joints and convential stucco have similar characteristics in that they are primarily made up or consist of sand. For example:
The Ratios for a covential general building stucco system are as follows:
sand : cement sand : lime : cement
That's alot of sand. Don't get me wrong, it can be done. But it has to be done professionally. Pointing for brick or block, sealing, parging, wrapping, priming and finally finishing is the way to properly apply either elastomeric or acrylic paint or finish over masonry walls. If it is done any other way, then the system will fail eventually and then everybody and the next guy will blame the EIFS finish for the delamination. It never fails.
I understand what your are saying and it is correct.
Sand has been used for more than 2000 years in stucco and I have never heard it will prevent a proper bond. Loose dirt on the surface like what your are talking about is another thing.
We usually put an extra thick scratch coat on first. Let the scratch coat dry and crack. We then apply the brown coat. We let the brown coat sit for about 4 weeks, then apply your color coat. This method isn't perfect, but it works pretty good. Adding a fiberglass mesh in the mix doesn't hurt, especially if you are going to have a smoother style texture.
Pavola: you can purchase an adhesive that you can roll on the wall. A primer coat of sorts. Then you can stucco on top of that. Don't color coat directly on top of paint, or your color coat will just flake away.
I don't have a clue about stucco so pardon my question, but can't you get the texture you want and then paint? What's the color coat? We were trying to figure out a way to smooth over the block and have the stucco look, but am I asking for problems without doing the whole process?
You can texture and then paint, but then that makes it a two part process, and you will have to repaint in the future. The color coat is a texture coat with a box of color mixed in. You just dump a box/bag of color in with your texture when you are mixing it up and you are good to go. I would recomend looking at the La Habra, or Expo websites for more info on color. Also, if you are going to apply a texture coat over a block wall then you should apply a brown coat first. That way you wont be able to see any of the block joints. Hope that helps.
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