Paint failure and LEED

Archive of Older Topics Archive - Specifications Discussions #2
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We are involved in a project that will be LEED Certified (our first LEED project). At this point in the construction, it has become apparent that there is paint failure occurring on the interior field painted steel doors and handrails. Due to the fact that water-based coatings were required in this project to meet the LEED low-VOC requirements, the paint is not curing successfully and not bonding well to the manufacturers primer. The well-known national paint manufacturers representatives response after visiting the site is, “Well, that’s what was specified,” and “Waterborne coatings will never perform as sucessfully as alkyds.” Our independent LEED Consultant’s response is something along the line of “Sorry about your problem - but absolutely no deviations from my product/manufacturer recommendations in order to achieve the LEED credit.”

My question as the specifier is this: When does common sense and logic take over in this process and allow some limited leeway to specify coatings that we know will work well and perform successfully, i.e. Alkyd paint? Or, is the solution simply to ignore trying to get the one additional credit for Low-VOC paint and go with what we know will work until the paint industry comes up with a line of products that will perform? Am I missing something?

Has anyone had a similar problem in your LEED projects, and what is the thinking on a remedy?

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LEED allows you to use an average VOC per liter for the entire project. If you search the credit interpretations you can find the formula and examples. I have used this sucessfully to when paints with higher VOC’s were required, but we still had a lot of low or no VOC paint.

I would question the paint representative response. We had failure on some roof deck and the paint rep. questioned the thickness of the paint. We had the paint apply additional coats and it solved the problem.

3

That problem has nothing to do with LEED requirements. More likely than not you’re looking at insufficient prep.

LEED doesn’t contravene ‘common sense’ either. Low VOC paint on interior doors is not going to achieve a point. It’s the project response to the criteria that is the goal.

Are you LEED accredited?

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I typically specify a water borne epoxy coating (Tnemec or some such) for doors and door frames. the material performs as well as the old alkyds did; the smell is minimal; it can be touched up in the field, and while the VOCs are not really low, they are low enough to make the numbers work.
I do agree with the prep issue, and we have found (and have been told by paint reps) that the very low VOC products simply are not performing as well as the products with more vehicle in them and require more frequent maintenance. I think it will take a while for the technology to settle out.

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“LEED allows you to use an average VOC per liter for the entire project.”

Now there’s a real interesting math problem.

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I have to agree with Doug.
Preparation is 90%.
Also look at compatability of primer with top coat. I typically specify primers by same manufacturer as top coat and specify it as a system and require the applicator to develop the procedures for prep and application with coating manufacturer.

I would look into polyurethane top coats in lieu of epoxies as they tend to have lower VOC’s than the epoxies.

As for your LEED consultant’s response - he needs to do more research on the products before he becomes so adamant about it. (See Russ’ response)

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As for the math problem it is not as hard as it seems. Most painters can provide the quantity of paint for each type and a simple excel spreadsheet can crunch the numbers.

I agree that prep is the most important part of painting. It can be way to easy to blame it on the paint type. Water based products are getting better and better all the time.

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Sorry this is so long, but it is from my most reliable coatings source-- rep of a major manufacturer;

Common sense may not be required in this situation but, rather, a little understanding of the properties of these two coating types.

First, the manufacturer’s representative quoted was correct but wrong.

Correct in that it appears that waterborne coatings were specified.
Incorrect that they may not perform as well as alkyds.

Simply put, waterborne coatings (acrylics, alkyds, epoxies, urethanes) ARE, in fact as good as their solvent borne counterparts and often “better”. But that does not mean that they are “as good as” as soon as. Here’s what I mean…

An solvent borne alkyd coating cures by solvent evaporation and oxidation. It could be dry-to-touch and “hard” in a number of hours or a day or so. A waterborne acrylic coating, in contrast, cures by “solvent” evaporation and coalescence. “Cure” of a waterborne acrylic coating is a mechanical process, if you will, versus the chemical process represented in the cure of a solvent borne alkyd. Because of that, a waterborne acrylic coating may take longer to achieve its full performance properties (adhesion being one of them) compared to a solvent borne alkyd. Check the manufacturer’s data page: it may state something like “full cure in seven days”. Or perhaps a bit longer.

Given that “slowerness” to achieve full “cure”, once it is achieved a waterborne acrylic coating may have twice the surface adhesion (tensile) of a solvent borne alkyd. Further, while the alkyd coating will chalk and fade with exterior exposure (solvent borne AND waterborne versions), the acrylics will not. And they’ll remain more flexible. And they resist flaking and peeling. And they’ll be easier to topcoat. And they “breathe”. And they’ll adhere to more substrates directly (like concrete and masonry and zinc-coated metals)… Need I go on?

When specifying and using waterborne acrylic coatings, remember that common sense should tell you that their numerous benefits come at a cost. The “cost” could be a softer film until full cure is achieved.

BTW, this is may not be true with all the other waterborne versions of existing coatings. Check with the manufacturer.

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I’m with Ralph.

Side note -
Usually when given a choice between the paint (insert inanimate object here) being at fault, or the human being at fault, it’s generally the human being who is more capable of assuming responsibility.

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Ralph,
I think your comparison the two materials is very good, and I’m familiar with these characteristics. One question: you state that until acrylics are cured “a waterborne acrylic coating may have twice the surface adhesion (tensile) of a solvent borne alkyd.” Are you refering to peel adhesion? (Which of course you couldn’t really measure until cured.) Or do mean the internal stress in the film?

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I would also question the paint representative on his ability to stand behind their products. If the paint manufacturer is not going to stand behind their products or not question the preparation, I would not use them again. I can not belive that they said “Well, that’s what was specified” if that is what their paint system indicates.

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I agree with Marvin. I generally try to involve the paint rep., especially with higher performance coatings like Carboline, ICI/Devoe, & Tnemec, in the specification of the systems during CD’s.
This has also helped when the contractor trys to submit a substitution that is of lesser quality.

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John, this is from my coating source:

"You’re correct: you shouldn’t measure adhesion until the coating is properly (fully) cured. Including alkyds.

Not exactly ‘peel’ adhesion though because, it is demonstrated by paint being removed with a lateral / diagonal force, if you will, as well as a possible perpendicular force.

The adhesion noted earlier is exemplified by ASTM D4541 testing which measures only the tensile (perpendicular) force required to remove a coating - if, that is, it can be removed.

This is also not to be confused with coating film cohesion: the ability of a coating to stick together ‘internally’ and resist splitting itself in two.

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Ralph, following up, restating your words so I can be sure I understand. During film curing phase, acrylics have twice the adhesion than alkyds. I ask because the originator of this thread had a failure with an acrylic. If acrylics generalyl out-perform alkyds in adhesion (which has been my understanding), then the finger is more clearly pointed towards preparation failure in this instance.

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It would be interesting to know whether the field paint was compatible with the shop primer. If the shop primer wasn’t selected for a waterborne finish coat, it might not be. (I see that Richard pointed this out, too.)

Not that this would solve your field problem, of course. But knowing why it happened this time could at least prevent its happening next time.

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Another interesting side note: the low-VOC coatings companies have a few different strategies to deal with new regulations in the South Coast Air Quality Management District (Los Angeles area) that kick in this July. If you’re doing work in Los Angeles, be sure to contact your rep early to find a compliant solution.

Some of the strategies in the near term include adding metal flake to change the paint from a category requiring low-VOC to a higher-VOC category, using stockpiled paint for up to 3 years, and, of course, the ever popular lawsuit to block the rule’s going into effect.

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Vivian’s point reminded me of a reasonable sounding recommendation that shop primers on hollow metal doors and frames and similar items be regarded as shipping primers only, and that a field-applied primer consistent with the finish coat be specified over shop primers on critical items. This could help get around compatibility and preparation issues.

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Phil’s got a good point. Our standard is to reprime doors and frames, and other shop primed items where we do not exercise control over the primer used. Exception: small or lower-end build-outs.