Joel Hirshberg June 22, 2017 Average reading time: almost 7 minutes
8 Solutions to the Most Common Paint Problems
Including real-life examples from our customers.
This applies to most water-based paint, stains, finishes, and coatings.
Real life example #1 about a tacky finish: Ken H. from Ohio asked I just purchased a water-based polyurethane from your company for the purpose of sealing and protecting my maple cabinetry. I performed a test on a sample piece of maple as you suggested, and it worked great.
However, when the contractor applied the same product to my unfinished cabinetry, he ran into many problems. He said the product remained tacky and would not dry properly. He also said it flaked off after the first coat and had a terrible odor. What is going on?
Answer in #3 below.
Regardless of the type or brand of product, all water-based paints, stains, and coatings have unique characteristics that require special attention before and during application in order to avoid failures. Improper application can lead to serious consequences, such as poor adhesion, bubbling or blistering, slow drying, and even strong odors.
8 Problems with Applying Water-based Paints and Coatings
Most of these points seem logical, but failures occur every day because someone simply ignored the obvious.
Read the instructions by yourself and then read with your contractor. If there’s something you don’t understand, download the complete instructions, which are usually posted on the right hand margin of our website. If you or your contractor need further assistance, feel free to contact one of our eco-advisors and allow us to help you through the installation process and find answers for your questions.
We highly recommend testing in an inconspicuous area to be sure that there’s good adhesion AND that you can tolerate the product once it is dry. For sensitive customers, we offer some Testing Guidelines that may be useful.
Good preparation will not only improve the appearance of your job, but it will also improve the adhesion and longevity. Cleaning before painting seems obvious on a hard, painted surface. Porous surfaces like wood, concrete, or stucco may look clean. These surfaces can have mold and mildew stains or invisible chemicals hidden beneath them that can wreak havoc on your paint or finish. These chemicals are not easy to identify and therefore not so easy to clean. Cleaning concrete is challenging and time consuming but needs to be done before any paint can be applied.
For example, brand new pine, spruce, fir and cedar often have gummy pitch on or below the surface that requires a light sanding and cleaning to avoid poor bonding. Concrete floors in basements or garages often have all kinds of caustic chemicals that have been spilled on them. They may be dry, but they are far from clean. Pressure-treated wood that has not been weathered for a year prior to finishing may also cause problems.
Once a water-based paint or finish is applied, an unanticipated reaction can take place with the chemicals beneath the surface that you don’t see.
Solution for the customer’s problem in real example #1 above. To everyone’s surprise, it turned out to be a cleaning problem.
After hours (actually days) of discussion about all the possible ways this could have happened, we discovered that the contractor had previously used an additive in his spray gun called Floetrol (a solvent-based leveling agent used to make latex paint spray easier and smoother). He had neglected to clean his equipment adequately before spraying. The solvents left in the hose contaminated the polyurethane. As a consequence, the poly did not bond well to the unfinished wood, and it bubbled and eventually peeled off. It also smelled bad, which was a dead giveaway that something else was interacting with the original product. Once he cleaned his paint gun, everything was okay.
The same advice applies to your brush or roller. If they have not been thoroughly cleaned, they may still contain pollutants from previous jobs that will contaminate your current one.
Real life example #2 about cleaning: A GBS customer complained that the non-toxic paint she just applied to her painted walls was failing, and she demanded a replacement. She said that she cleaned her wall very carefully before applying our non-toxic paint. The paint did not stick at all and started peeling within hours.
After some lengthy questioning, the customer recalled that she had used a tack cloth purchased from a local hardware store to clean the walls. Unbeknownst to her, the tack cloth had left a residue that interacted and interfered with the bonding of the paint to the wall. This was not an easy fix. The customer had to sand off all the paint in her living room and start over. Yes, stuff like this happens. This is why we are sharing these true stories so you can avoid the consequences.
Tack cloths are commonly made of a cotton gauze and a resinous material, often a petroleum derivative, that’s designed to help pick up dust, dirt, grime, etc., or to remove oil and wax. These cloths may contain hazardous air pollutants (HAPs) and anti-static additives, fire retardants, dyes or performance-enhancing chemicals. They are also designed to be used with oil-based products exclusively. Watch out for tack cloths!
Always use cleaners that do not contain any oils, as they will also leave a residue. We recommend our AFM Safecoat SuperClean or HydroxiPro Cleaner to clean your dirty walls, ceilings, or floors. Then, use a new lint-free cloth, such as microfiber, (check our Perfect Clean Cloth here) that is rinsed only with water. Let the surface dry thoroughly before coating.
Priming is essential to create a suitable foundation that promotes good bonding. Priming is especially helpful when you don’t know what you’re painting over, such as oil-based paints or stains. A transitional or universal primer is designed to fill voids, stop bleed-through and build a solid basis for long-lasting adhesion.
Transitional primers can be applied over oil or solvent-based coatings without the need to sand off the previous finish. This can save time, money and the environment. Metal primers are specialized and work over many metals but usually won’t work over rusted areas. Check out our primers here.
If you live in an older home and suspect there is lead in the paint, it should be tested and, if necessary, remediated. Contact local authorities for certified professionals to remove the lead. You can also do your own testing with our EPA Lead Test Kits.
Real life example #3 about applying paint on a new wooden arbor: A GBS customer said: I applied two coats of your exterior paint to my new arbor. After a few weeks, your white paint turned a dark color and left brown spots in various places.
After some discussion, it was determined that the customer never primed the wood. The cedar was bleeding through both coats of paint. Ideally all the paint should have been sanded off, but a cheaper alternative was to apply primer over the paint and then re-coat with paint again. This was still an expensive proposition that could have been avoided with proper priming.
What about priming clear sealers? Unfortunately, when it comes to clear sealers like lacquer or polyurethane, there are no non-toxic water-based primers. To prep the surface: sand, clean and dry before application. The next step is to apply a thin coat and test for adhesion and a smooth, desirable finish. If you’re unsure of how well this will bond to the previous coat, you should wait overnight and then test. If it does not bond well, you may have to consider a different product.
A dry surface means one that is free of moisture, and a normal condition means 35-65% relative humidity.
Absolutely do not apply before, during or right after a rainy day. High humidity above 65% slows the drying process considerably. If you live in an area where it is always above 65%, you can control the humidity by turning on AC, ventilation, fans or extra heat, but you have to be scientific about it. If you don’t know what the humidity level is, buy a small hygrometer (check out our Hygrometers here). Make no mistake, high humidity is one of the biggest causes of paint failure and is the easiest to avoid.
Real life example #4 about drying:A GBS customer from Texas called and said that their clear sealer (Acrylacq) was still tacky after a month. Their contractor had applied three coats according to instructions, in the middle of summer, but it would not dry.
Water-based paints and finishes have a high amount of water; they require time to evaporate. Under normal temperature and humidity, they will skin over within a few hours, i.e., feel dry to the touch. However, they will continue to dry underneath the surface for hours or even days.
If the temperature becomes hot (85° F), water-based products will dry more quickly. However, if the humidity runs high (65%), the time required to fully dry can take 2-3 times longer than normal. That means 4-12 hours between each coat! And, as you might suspect, few contractors are going to wait around that long or come back to your home every 4-12 hours to apply another coat.
If a second coat is applied prematurely, before the first coat is dried, it slows the drying of the first coat. That’s what happened in Texas in example #4 above. It turned out the contractor was in such a hurry to finish the job, that he applied each coat after only 30 minutes. The combination of improper dry time plus high humidity resulted in a third coat that remained tacky and had no chance to dry on schedule. Instead, the customer had to wait about a month for all three coats to dry completely. And they did dry.
Real life example #5 about water-based stains: A contractor in the Rocky Mountains of Colorado applied a water-based stain on a very large, new, vaulted pine ceiling. Failing to read the instructions, he figured he could apply the stain on the entire ceiling, let it set over lunch and then wipe it off an hour later. Unlike oil-based stains, water-based stains can dry in 2-3 minutes, especially in a dry climate. Unfortunately, after lunch there was nothing to wipe off as it was completely dry. The result was ugly and much darker than the test sample that was wiped off immediately. The only solution was to sand off the stain or leave it. Ouch!
The bottom line is each product is different, and each environmental condition must be considered. Assuming all paints and finishes are the same and will dry at an equal rate will surely result in an undesirable end result.
The normal room temperature of 72° F is the ideal temperature for the application of most water-based finishes. Higher temperatures cause the evaporation rate to be too high and make it difficult to maintain a wet edge. The temptation is to turn on the AC to cool things down. However, air conditioning removes humidity from the ambient air. This will most likely make things worse. If you live in a dry climate, you will need to add humidity to the air to slow down the drying time. Again, check your hygrometer to see when the humidity reaches 35-65%.
If you’re working outdoors, only paint in the early morning or very late afternoon when the sun is almost down. Direct sun will dry out the paint or stain too quickly. Cloudy days are usually better, as long as it is not about to rain. It is also a lot more fun and easier on your body.
Colder temperatures (below 45°F) make finishes difficult to spread properly. Don’t paint or stain when evening temps dip below freezing, as this could ruin your entire job.
Faster drying and thinner paint create a tendency to apply the coating more heavily to make it cover better and stay wet longer. This is a mistake. Don’t overdo it by applying too thick, as it will slow down the drying process too much and could make things tacky. Always use the brush, roller or spray tip recommended by the manufacturer and adjust your speed of application or size of work area accordingly.
The use of thin, even coats and working in a smaller area are two solutions rolled into one that’s easy. Water-based products are generally thinner than oil-based products. Therefore, they dry much faster. Consequently, you’ll need to work in smaller areas in order to maintain a wet edge. Start by painting a small area (for example, 3’ x 8’) and see how quickly the paint dries out. It should stay wet long enough to blend with the next painted area. If that is not the case, due to higher heat or extreme dryness, you should work faster or change the size of your work area. This is especially true of water-based stains, which dry super fast.
If you apply over a surface that contains oil or solvents, even if it’s very old, it may not bond properly. Plus, the water in the new product may open up the pores and cause the previous finish to temporarily start off-gassing. Sometimes, solvents are trapped in the old paint or finish for years and then become reactivated. This happens more often when the new coat is applied heavily or when a second coat is applied before the first has a chance to dry properly. Even if your new product is completely non-toxic, zero-VOC, and low odor, it can still start a new chemical reaction, cause bubbling, reduce adhesion, and off-gas of the old stuff.
How do you know what is underneath? You can always ask the former owner, tenant, or contractor. You can also check the basement or garage for old paint cans laying around. But the best way is to test your new paint or finish in an inconspicuous place.
How to troubleshoot problems? The best way is to TEST first. If the new finish does not look right, smell right, or feel right, then STOP. Don’t continue in the hope it will get better and work itself out.
Test the product in a different environment and on a different surface to see if the results change. Usually they do. Try it on a clean, raw piece of wood, metal, or glass to see how it looks, feels, and smells. If it performs better on the new surface, then you know the problem was with the original surface or room condition. However, if there’s no change, then the problem may be with the product itself. Take a photo of the batch number on the top or bottom of the can and call the manufacturer or their dealer.