Secret to Selecting a Chalk Resistant Paint

Paint chalk is nothing more than broken down resin and pigment. A film of paint is basically like a very thick double decker sandwich (resin - pigment- resin - pigment - resin - pigment.......). A freshly painted surface has resin at the surface. You can prove this easily. After the paint dries, rub your finger across it. You will not have any pigment on your finger, it will be clean. However, do this same thing to a painted surface that has weathered outside for several years. Generally, you will get a film of pigment on your finger. The industry calls this chalk. The protective resin has broken down and left the pigment exposed. Thus, the key to chalk resistant paints is to purchase one that has quality resins and a high content of these resins. Since we already know that the resins are one of the most expensive ingredients in paint, you will probably pay a higher price for a chalk resistant paint. Beware of inexpensive paints and the claims they make!

To select a chalk resistant paint, you will need some very basic math skills. Most paint manufacturers list the contents of the paint on the side of each can. The contents are generally shown as two categories: PIGMENTS & VEHICLE. They are generally expressed as a percentage of the total volume. These categories are usually broken down again. The PIGMENTS will list various compounds which make up the pigments. The VEHICLE will list the amount of resin, any additives, and amount of solvent. Your mission is actually quite simple. To begin with, look for a paint that has a high vehicle percentage. Then, look to see if the resins comprise approximately 30 -35% of the total of the VEHICLE. If both of these values are high, you will be selecting a paint that has a very high total resin content. That is the secret.

Remember, the resin in the paint holds everything together. A high quality resin will resist breakdown. Also, the higher the ratio is between resin to pigment means that the pigment particles will be surrounded by that much more resin. This will make it harder for the pigment to get to the surface, where it appears as 'chalk'.

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Chalk Resistant Paint Characteristics

Many people take paint for granted. They feel that it is a simple product which requires little understanding or training to work with. This is a misconception. Paints are highly sophisticated products. There are many, many different types all with specific formulations. Most paint manufacturers have chemists with PhD's that constantly work with the ingredients of paint in an effort to improve them. The chemistry of paint is not as simple as you or I might think. In fact, some paint formulas are highly guarded secrets.

The paints that you or I use on our houses naturally breakdown. The sun, water, chemicals found in rain water, etc. can cause paint to deteriorate. It is a natural process, as many objects exposed to the elements naturally deteriorate. Because of this, it becomes a challenge to locate, purchase and apply a paint which will not readily breakdown. In order to accomplish this, I feel it would be beneficial for you to understand what characteristics make paint long lasting and chalk resistant.

Most paints are made up of three primary ingredients. These ingredients are pigments, resins, and vehicle. Some individuals prefer to express the vehicle as a combination of two ingredients, solvents and additives.

The pigments are the ingredients which give paint its hiding ability. They also give it its color. A paint without pigment would be very similar to varnish or urethane, basically it would be clear. Pigments can also help to block the corrosive effects of liquids or vapors. They can also be formulated to minimize the effects of ultraviolet radiation (the sun's rays).

Resins for the most part are the most important ingredient of paint. These materials give the paint its ability to 'stick or adhere' to things. The resins also surround the pigments and enable them to stick together as well. Remember, for the most part, resins are formulated to be clear, so you can't really see them. That is why they can surround the pigment and give a uniform color or appearance when dry. The resins can be formulated from many different compounds. Oil based paints have alkyd resins. Latex paints have acrylic resins. Epoxy paints have epoxy resins. So, as you can see, there are different resins, all with different levels of quality. For the most part, resins are the most expensive ingredient in paint. So, if you were a paint manufacturer and you wanted to make more money, what would be the first ingredient that you would try to minimize??? Are you starting to get the picture?

The vehicle is that part of the paint which enables it to be a liquid. If paints didn't have vehicle, they would be solid chunks in the paint can. How would you apply them? Paint manufacturers figured this out a long time ago. They knew that they wouldn't sell much paint if people couldn't use them. For the most part, the vehicle in paint evaporates shortly after you apply paint. This part of the vehicle is called a solvent. The solids (pigments, resins, additives) are left behind on the object you painted. Different paints have different solvents. Oil based paints usually have mineral spirits or turpentine as their solvent. Latex paints consider water as their solvent. Some paints have alcohol as a solvent. The solvents in most oil based paints are considered to be volatile organic compounds (hydro-carbons). These compounds cause air pollution when they evaporate. In liquid form (paint thinner or mineral spirits) they can pollute soil or water. Some states limit the use of these compounds in paint. In the future, it may be almost impossible to purchase 'oil' based paints. Paint manufacturers are responding to this challenge. They are attempting to formulate latex or acrylic paints that have the same durability as oil paints.

Related Articles:  Tips, Chalk Resistant Paint, Peeling Paint

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Painting Technique - Backpriming / Sources of Water & Water Vapor

Water is a very interesting compound. It is a basic necessity for life, yet it can be one of the most destructive forces that we encounter as homeowners. Water can shorten the lifespan of many building materials and finishes. Paint is very susceptible to damage caused by water and water vapor. Water vapor can cause a paint job to fail in as little as a week. Homeowners who have had encounters with water's destructive force quickly gain respect for it.

Backpriming is a simple painting technique which is frequently eliminated during the construction process. Because backpriming of exterior wood siding and trim can only be performed before wood products are installed, homeowners and builders should give serious consideration to this very helpful step in the painting process.

Backpriming involves the process of coating all surfaces of a piece of wood with paint or any other coating which will inhibit water or water vapor from soaking into the wood. Backpriming requires the use of slightly more paint and a little additional labor. However, the money invested in this process will pay huge dividends as long as the wood is in place. The paint or other coating which is applied to the 'back' side of the wood and other hidden edges will, for the most part, last indefinitely. Backpriming will significantly extend the performance of the initial and all subsequent paint jobs.

Paint is a coating which 'sticks' to wood or other surfaces which are painted. However, water vapor pressure can easily cause paint to lose its grip on wood. Water vapor pressure develops because of evaporation. Water, which enters wood through any number of ways, naturally wants to evaporate or turn into water vapor. You see this happen virtually every day. Laundry dries, water evaporates from your driveway, soil, hair, etc.

The evaporation process, if inhibited, causes pressure to build. Eventually the pressure becomes great enough to overcome the adhesive properties of the paint film. Bingo, you have a blister or an area which peels and flakes. The water or water vapor which causes this to happen can originate from various sources. Several are as follows:

Bath & Kitchen Exhaust Fans

These fans have the ability to concentrate and discharge massive quantities of water vapor. Cooking and bathing activities generate large amounts of water vapor, especially if the water is warm or hot. The ductwork which connects the fan to the outside discharge point can be a problem area. If this ductwork is loosely fit, moist air can escape into a wall or ceiling cavity. This water vapor, in its attempt to escape into the atmosphere, quite possibly will encounter a piece of painted wood. If the wood is not backprimed, you will have a problem.

Clothes Dryer Vents

Clothes dryers also produce large amounts of water vapor. This water vapor must not be allowed to vent inside of a house or attic area. The dryer vent must be a sealed ductwork connection straight from the dryer to the outside of your house. Also, attempt to locate the dryer discharge vent in such a way that the exhaust air can get away from your house as quickly as possible. Avoid putting these vents in attics in cold climates. The smallest leak in the ductwork can cause tremendous condensation problems.

Air Conditioner Condensate

Air conditioners, through the cooling process, extract water vapor from the air. This water then drains from the air conditioning unit. Window air conditioners are the biggest problem. The water can drip onto wood siding or windowsills. This water can find its way into a crack or bare spot and then soak into the wood. Eventually large areas of paint are peeling or blistering. Try to pipe this water away from painted surfaces.

Interior Humidifiers

Houses which have humidifiers attached to their heating systems can have serious paint peeling problems. If the humidifier is set too high, the water vapor which is in the air inside of the house can find its way outside. If you have wood siding, the water vapor may condense back to a liquid on the back side of the wood. If the wood hasn't been painted, the water will soak into the wood and come out on the other side, just beneath your paint. Set the humidifier so that just enough moisture is in the air which makes you feel comfortable.

Crawl Spaces

Crawl spaces which are unvented or lack vapor barriers can be problem areas. Water constantly is evaporating from the soil beneath your living space. That water vapor wants to get into the air outside of your house. It will push the paint off your house if it gets in the way. Install a good vapor barrier (minimum 6 mil plastic) over the soil in the crawl space. Make sure that there are vents in the foundation to let moist air out before it gets to any painted wood.

Surface Water

Surface water is any water which hits the outside of your house. Some you can control and some you can't. For example, it is next to impossible to stop rain from hitting your house. However, you can control or adjust lawn sprinklers, hoses, etc. from spraying water onto your painted surfaces. If there is the slightest break in the paint film, water will find its way into the wood. If enough water gets into the wood, peeling and blistering will result.

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Backpriming Tips

Backpriming is really easy to do. It just require a little more paint and some space to stack the wood pieces while they dry. The effort which you invest will be worth it, trust me.

I have found that applying the paint with a paint roller works extremely well. I usually set up a painting table on sawhorses. The table can be made from scrap pieces of wood or pieces of plywood. It can simply be a long (16 foot) 2 x 12. You want something rigid, because the pieces of wood which you will paint are flimsy. Simply place the wood siding or trim piece on the table and roll the back side first. Just after painting this, paint all the edges. The only remaining area left to be painted should be the finished side which will show after the siding or trim is installed. Pick up the piece of wood and lay it somewhere to dry or lean it against the exterior of the house. If you use a quick drying latex primer it can often dry in as little as an hour. Consider using latex surgical gloves, as you will be getting paint on your hands.

The next step is to paint the unfinished side. Do this in the same manner as the first, however add one final step. Roller textures are fine for inside house walls. However, if you are using smooth siding and trim, brush texture looks better. I apply the paint with a roller and then glide a brush over the paint to make it look as if it was applied with a brush. It's quick and easy. Make sure you leave the brush in the paint can or roller pan when you are not using it. The primer will dry on the brush and cause problems.

Consider applying the second finish coat of paint before the wood is installed. This will eliminate ladders and scaffolding from being set twice or three times by the painters. This should save some money.

Also, don't forget to paint the ends of the wood. This is where 'end grain' is visible. These ends must be painted. This is where water can most easily enter wood!!! The carpenters who install the wood must be instructed to paint each edge in the event that they cut a piece of siding or trim. They will probably cut every piece! This effort is a must. The carpenters will grumble, but explain to them the importance of this very critical step.

Always make sure that you use the correct primer. Do not use top coat or finish coat paint as a primer!!!!! Primers are formulated to be more sticky. They will adhere better to unpainted wood, and finish coats will adhere better to primers. If you are not sure, ask the paint supplier. Ask for bulletins or manuals to read. The paint companies want you to use the right products. They don't want the paint to peel either! They want you to buy their paint in the future. Ask them for help and advice.

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