THE PURPOSE OF PAINTS AND STAINS - PART II
This is part 2 of a 2 part series of articles on paints and stains.
Problem Solved - Finally, Interior Paints Coatings for Every Job
Do you ever wonder about the difference between interior and exterior paints? I once used exterior paint on an indoor ceiling, reasoning that it would last longer. It could endure longer, but as I found out when I was required to touch up the ceiling only 2 years later, exterior paints will discolor on an interior surface. Exterior paints contain special additives made to withstand the outdoors. Interior paints have additives that help the paint dry out to a durable, uniform surface finish.
A lot of the advances in painting technology have been with latex. Actually, latex has overtaken oil-based paint in several areas: toughness and elasticity, as well as ease of application, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, including the Pristine lines made by Benjamin Moore, are created without VOCs in any way. Today's latexes are created with higher quality pigments and binders that give them more body, so they go on thicker.
Latexes enjoy quite a bit of attractiveness for interior applications, specifically for walls and ceilings. Alkyds stay the professionals' choice for trimming work because oil based paints are much easier to paint on detailed areas like molding and hardwood trim. However, that traditional school of thought is gradually changing as better latexes, including Pratt & Lambert's Accolade Interior Acrylic Semi Gloss, are introduced to the market.
Take The Headache Out of Finding Exterior Paint Coatings
Moisture is an important concern for exterior paint selection. Each day a family of four will create several gallons of vaporized water in the house.
Coupled with naturally occurring humidity, this can mean a lot of moisture moving through the surfaces and siding. Wetness is highest in the baths and kitchen. If these rooms aren't sufficiently ventilated, water will migrate through the wall space. Vapor barriers help contain wetness, but vapor always seeks to leave. The structure of a home, the kind of vapor barrier they have, ventilation, and humidity all make choosing the right paint critical.
In wetter climates you require a paint that will let moisture go through the wood, so water doesn't get trapped under the paint and cause blistering and peeling. Latexes are porous and let moisture go through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with floors that expand and contract, as wood will, especially in colder climates. Latex paints have more elasticity, allowing better adhesion.
I favor using latex on all exterior surface areas, including wood siding, stucco, and concrete. Latexes resist fading better than most oil-based paints, and they'll cover either oil-based or latex primer (most oils have to go on top of an alkyd primer).
Latexes perform a great job of covering concrete. Despite its hardness, cement is very porous, and oil-based paints don't always adhere well. For very best durability, I would recommend latex enamel.
In general, if I know of a latex product that will provide superior performance, I'll choose it over an oil-based product that needs to be cleaned with a thinner.
Latex only requires water. Thinners add yet another cost, are hard to get rid of, and usually end up spattered on my skin or clothes, no matter how careful I am.
Improve Your Interior Staining
You may spend a life time studying stains and sealers, but there is nothing mysterious about them. The bottom line in figuring out which stain to make use of is to familiarize yourself with the products available. Scan the label, along with any product information you can get, and talk to the personnel at a professional paint shop.
Outside stains come in oil based, varnish, polyurethane, and water-borne solvents. Stains have less colorant than paint and much more solvents, giving them increased wood penetration. Waterproofing is a priority with exterior stains. Most come with built-in sealants to increase sturdiness and help maintain the wood. The color in stains can be pigments, dyes, or both. A semi-transparent stain has more dye for grain penetration. A solid stain has more pigment for surface covering. Pigment is a finely ground coloring that doesn't penetrate the grain as deeply as a dye. That's why a pigmented stain is actually used along with a sealer such as urethane or varnish.
Some high quality interior stains have dyes to penetrate and pigments to draw out the richness of the grain. Others contain only pigments, that are much easier to apply, mix, and touch up. Pigmented stains are lighter in color and bring out more of the wood grain. If you're looking for darker results, a dyed stain will provide what you would like in one layer (make sure to use a conditioner on porous wood, such as pine and birch wood, to avoid splotching). Dyed stains are extremely difficult to touch up. Every coating eventually will require touching up, so make sure to consider the ease of maintenance in your use of stains. You'll get the best results by using better stains such as Minwax, Pratt & Lambert's Tonetic, Pittsburgh's Rez, or Wood-Kote.
If you wish to avoid the watery nature of stains, try a gel stain, which had the majority of the water solvent removed. Gels are simple to use. They wipe on, dry out fast, and cover evenly. Because they're colored with pigment, gel stains don't penetrate that well. They're a great choice for porous woods that are difficult to coat evenly with out a toner. Gel stains do a great job of bringing out the grain on embossed metal or composite surfaces. I don't recommend working with them for hardwoods, which need a good dye stain to emphasize the depth and beauty of the grain.
Sanding Sealers Are an Exciting Paint Product
Sanding sealers are interior primers that both penetrate and seal wood. You should use them under clear coats or on top of stains as sealers. Sanding sealers are different from a sealer like polyurethane, which is not designed to prime. They're similar to varnish, but diluted with solvents to permit better penetration for priming. The hardness of varnishes and lacquers inhibits them from soaking into the wood pores. Sanding sealer can provide a better adherence for clear coats.
Shellacs tend to be added to sanding sealers to fortify the resin and offer an instant drying agent. In addition they add an amber tone, so if you're by using a sanding sealer with shellac, make sure it will not impact the stain. Shellacs tend to yellow aver time and contain toluene, that has a very high VOC content. Shellacs are gradually giving ways to new sanding sealer formulas with lower VOCs and better performance.
Alkyd resin sanding sealers also have high VOCs, although significantly less than their shellac based cousins. Pittsburgh Paints makes a slow drying alkyd resin sanding sealer without shellac called Rez 77-1. This specific primer/sealer is good for both interiors and exteriors. Pratt & Lambert's Latex Sanding Sealer has suprisingly low VOCs, but is purely for interior wood and must not be used under a water based polyurethane.
Oil-based sanding sealers can also be used to seal outside wood, especially decking, which is continually exposed to sun and water. For color uniformity in areas like decks, you need to completely coat, or back prime, the lumber before it goes up, using the same sealer or stain. Olympic Water Guard, Messmer's UV Plus, Behr's, & most top quality deck stains are excellent water repellent sealers that also can be used for priming exterior wood.
Improved Wood and Stain Sealers for Interior Wood
Sealers, including varnishes, lacquers, urethanes, and shellacs, are put into the stain itself, applied as a top coat over a stain, or used as a clear coat on unstained wood trim. They could be used for just about any type of wood trim, including windows, entrance doors, and the casing around them. Although you can purchase stain/sealer combinations, they have a tendency to yellow, are difficult to maintain, and don't last as long as separately applied stain and sealers.
Varnishes contain natural oils such as Tung oil, an extremely hard, durable sealant that can be brushed on and dries slowly. Varnishes are easy to completely clean and maintain with soap and water followed by a wiped on varnish, which often keeps a wood surface looking ideal for years. Make sure there's no wax in your cleaner, because wax clogs wood pores. I prefer to work with Hope's Tung Oil varnish for a wipe-on maintenance coat. Lacquer is a quick drying sealer that more often than not must be sprayed, since it becomes tacky almost immediately.
Polyurethanes do almost anything shellac can do, but they're much easier to maintain. While shellacs act like paint, polyurethanes act more like a clear coating that permeates the wood instead of sitting on top of it. Polyurethanes brush on and dry out quickly, with little scent and VOCs. They have more or less replaced shellacs as a clear sealer. Another reason urethanes have become such popular sealers is the fact that they don't require sanding sealers.
The smells associated numerous paints and stains can be more than just offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs provide a very hard covering but contain high VOC levels. Water borne sealers, like the stains, match the performance of several solvent based sealers, with fewer VOCs. The VOC content of water based sealers such as Sherwin Williams Kern Aqua Lacquer average about 250 grams per liter, or 2 pounds per gallon, half the most common VOCs of oil-based lacquers. The ethers in water based sealers aren't combustible, another advantage, but they still have enough VOCs to warrant a respirator.
Although they resist yellowing, water borne sealers such as acrylic latex polyurethanes do tend to raise the grain. They'll also harden or "flash off" quickly at conditions greater than 60°F. The very best working temperature for nearly all water borne acrylic latex polyurethanes is between 50°F and 60°F, which lets them flash a little more slowly. In this case, flashing-off simply means that the solvent evaporates and leaves the resins to finish the drying out process. A contractor I knew once used water based latex polyurethane sealer that flashed off so fast he could only apply it between 5 A.M. and 9 A.M. Anything later than that was too warm.
Minwax makes very good water borne polyurethane, as do Pittsburgh, Pratt & Lambert, Benjamin Moore, among others.
Stains and Sealers for Exterior Applications
Because of their better penetration and sealing ability, most exterior stains sold today are oil-based. However, oil-based solid stains peel off as they grow older, making them more challenging to maintain. A solid stain is similar to paint: It coats more than it penetrates. A latex solid stain peels less and is also easier to maintain as it ages. However, I prefer oil-based products for semi-transparent stains. Added oil solvents let them penetrate deeper. A number of the better stains on the market include Pittsburgh Solid Color Latex Stain, Messmer's U.V Plus, Moorwood Solid Color Exterior Stain, Sherwin Williams Woodscape stains, Pittsburgh Semi-transparent Exterior Stain, Rez Deck Stain by Pittsburgh, and the Sikkens Cetol system.
Deck stains will often have more solids when compared to a typical outside stain, which make them stronger. I recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until just lately, the major problem with outdoor stains was their low UV resistance, but newer trans-oxides have finely ground metal mixed in for better protection. A high end deck stain won't need a different sealer coating, although you can add one (such as Olympic Water Guard) if you think extra protection is needed to fight wetness and sun exposure. Better deck stains retail for about $35 a gallon and cover 300 to 400 sq. ft.
Avoid using deck stains that contain silicone. Despite their attractive price, they are not a good deal. Advertisements for silicone stains and deck sealers often show beaded up water over a deck, and many people are fooled into thinking that this is the indication of a successful coating. However, silicone breaks down quickly, usually in a matter of months, producing a discolored, waxy coat that is a pain to eliminate. The deteriorated silicone also ceases repelling water.
"High build" coatings such as Sikkens and Messmers work remarkably well on outside siding, but they are too soft to be utilized on your deck. Stripping these coatings can take gallons of wood cleaner and a significant amount of work.
Water based exterior stains, such as Sherwin Williams Woodscapes, incorporate the features of oil-based and latex coatings. They run and drip less than oil based stain, and dry faster, allowing for two coatings the same day. Water based stains possess the resilience and versatility of any latex stain, giving them stamina. They're a great choice for most applications. However that cleaning up water based stains calls for work. You can find a couple of oil components in the solvent which may have to be cleaned. First use soap and water, then alcohol. Ask your dealer for specific cleaning directions for water based stains, and scan the label.
Ask Questions When In Doubt
If you still have questions about which paint or stain to use, please ask people in the know. An experienced, proficient salesperson can clear up any questions it's likely you have. Choose a paint store with staff having at least a decade of experience in the business. Inquire further what has worked best for your particular application and ask to read a spec sheet on the merchandise in question.
The answers you get will be based upon whom you ask. A paint store will try to market you one of their products, after all, that's why they're in business. Painting contractors might not be impartial, either. They need to sell their expertise. I get tons of calls from people looking for assistance with their painting problems. Most painters, including myself, don't mind giving an hour of time, but if you want comprehensive answers, consider finding a contractor for a professional evaluation. Rates vary, but I charge about $60 for a written and oral examination, depending on the traveling time included. A paid evaluation will let you know whether you should paint, stain, or re-side, as well as which coating might be best for your project. Each painting job has unique conditions that require specific answers.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
