This is part 2 of a 2 part series of articles on paints and stains.
Interior Paints Coatings for Each Job
Do you ever wonder about the difference between interior and exterior paints? I once used exterior paint on an inside ceiling, reasoning that it could last longer. It could last longer, but as I found out when I had to touch up the ceiling only 2 yrs later, exterior paints will discolor on an interior surface. Exterior paints contain special additives designed to withstand the outside. Interior paints have additives that help the paint dry to a durable, uniform finish.
Most of the advances in painting technology have been with latex. Actually, latex has overtaken oil-based paint in several areas: strength and elasticity, as well as ease of application, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, like the Pristine brand made by Benjamin Moore, are created without VOCs whatsoever. Today's latexes are made with top quality pigments and binders that give them more body, so they go on thicker.
Latexes enjoy quite a lttle bit of attractiveness for interior applications, especially for walls and ceilings. Alkyds remain the professionals' choice for trim work because oil based paints are much easier to paint on detailed areas like molding and trim. However, that traditional school of thought is gradually changing as better latexes, including Pratt & Lambert's Accolade Interior Acrylic Semi Gloss, come on the market.
High Demand Exterior Paint Coatings
Moisture can be an important concern for exterior paint selection. Each day a family of four will generate several gallons of vaporized water inside a house.
Coupled with naturally occurring humidity, this may mean a a large amount of moisture moving through the surfaces and siding. Water is highest in the baths and kitchen. If these rooms aren't sufficiently ventilated, water will migrate through the wall space. Vapor barriers help to contain wetness, but vapor always seeks to escape. The structure of a home, the kind of vapor barrier it has, ventilation, and dampness all make selecting the right paint critical.
In wetter climates you require a paint that will let moisture pass through the wood, so water doesn't get trapped under the paint and cause blistering and peeling. Latexes are porous and let moisture pass through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with surfaces that expand and contract, as wood will, especially in colder climates. Latex paints have more elasticity, allowing better adhesion.
I favor using latex on most exterior areas, including wood siding, stucco, and cement. Latexes withstand fading much better than most oil-based paints, and they will cover either oil-based or latex primer (most oils have to go over an alkyd primer).
Latexes perform a great job of covering cement. Despite its hardness, concrete is very porous, and oil-based paints don't always stay well. For ideal durability, I recommend latex enamel.
In general, if I know of a latex product that will provide superior performance, I will choose it over an oil-based product that should be cleaned with a thinner.
Latex only needs water. Thinners add yet another expense, are hard to dispose of, and usually end up spattered on my skin or clothes, regardless of how careful I am.
Improve Your Staining for Interior Work
You may spend a life studying stains and sealers, but there's nothing mysterious about them. The bottom line in figuring out which stain to use is to become acquainted 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.
Exterior stains come in oil based, varnish, polyurethane, and water-borne solvents. Stains have less colorant than paint and more solvents, providing them with greater wood penetration. Waterproofing is important with exterior stains. Most include built-in sealants to increase sturdiness and help preserve 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 is why a pigmented stain is obviously 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, combine, and touch up. Pigmented stains are lighter in color and draw out more of the wood grain. If you are looking for darker results, a dyed stain provides what you would like in one overcoat (make sure to use a conditioner on porous wood, such as pine and birch wood, to avoid splotching). Dyed stains are almost impossible to touch up. Every coating eventually will require touching up, so be sure to consider the ease of maintenance in your choice 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 want to steer clear of the watery nature of stains, get a gel stain, which had most of the water solvent removed. Gels are easy to use. They wipe on, dry out fast, and cover evenly. Since they're colored with pigment, gel stains don't penetrate that well. They're a good choice for porous woods that are troublesome 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.
No-Fuss Painting Using Sanding Sealers
Sanding sealers are interior primers that both penetrate and seal wood. You can use them under clear coats or over stains as sealers. Sanding sealers are different from a sealer like polyurethane, which is not made to prime. They're more like varnish, but diluted with solvents to allow better penetration for priming. The hardness of varnishes and lacquers stops them from soaking in to the wood pores. Sanding sealer can offer a better adherence for clear coats.
Shellacs are often added to sanding sealers to strengthen the resin and offer an instant drying agent. They also add an amber tone, so if you're utilizing a sanding sealer with shellac, make sure it won't influence the stain. Shellacs have a tendency to yellow aver time and contain toluene, that has a high VOC content. Shellacs are gradually offering ways to new sanding sealer formulas with lower VOCs and better performance.
Alkyd resin sanding sealers also have high VOCs, although less than their shellac based cousins. Pittsburgh Paints makes a slow drying alkyd resin sanding sealer without shellac known as Rez 77-1. This particular 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 shouldn't be used under a water borne polyurethane.
Oil-based sanding sealers can also be utilized to seal exterior wood, especially decking, which is constantly subjected to sun and water. For color uniformity in areas like decks, it's best to completely coat, or back prime, the lumber before it is in place, using the same sealer or stain. Olympic Water Guard, Messmer's UV Plus, Behr's, and most top quality deck stains are great water repellent sealers that also can be utilized for priming exterior wood.
Improved Wood and Stain Sealers for Interior Wood
Sealers, including varnishes, lacquers, urethanes, and shellacs, are added to the stain itself, applied as a top coat over a stain, or used as a clear coating on unstained wood trim. They could be used for any type of trim, including windows, doorways, and the casing around them. Although you can purchase stain/sealer combinations, they have a tendency to yellow, are difficult to keep up, 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 clean and maintain with soap and water followed by a wiped on varnish, which often keeps a wood surface looking great for years. Make sure there is no wax in your cleaner, because wax clogs wood pores. I favor to work with Hope's Tung Oil varnish for a wipe-on maintenance layer. Lacquer is a fast 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 quickly, with little smell and VOCs. They have more or less replaced shellacs as a clear sealer. Another reason urethanes have grown to be such popular sealers is that they don't require sanding sealers.
The smells associated numerous paints and stains can become more than just offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs provide a ultra hard coating but contain high VOC levels. Water based sealers, like the stains, match the performance of many solvent based sealers, with fewer VOCs. The VOC content of water borne sealers such as Sherwin Williams Kern Aqua Lacquer average about 250 grams per liter, or 2 pounds per gallon, half the usual VOCs of oil-based lacquers. The ethers in water borne sealers aren't combustible, another advantage, but they still have sufficient VOCs to warrant a respirator.
Although they resist yellowing, water borne sealers such as acrylic latex polyurethanes do have a tendency to raise the grain. They'll also harden or "flash off" quickly at conditions higher than 60°F. The very best working temperature for nearly all water based acrylic latex polyurethanes is between 50°F and 60°F, which lets them flash a bit more slowly. In cases like this, flashing-off simply means that the solvent evaporates and leaves the resins to finish the drying process. A contractor I know 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 get 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 much easier to maintain as it ages. However, I favor oil-based products for semi-transparent stains. Added oil solvents let them penetrate deeper. A number of the better stains on the marketplace 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 usually have more solids when compared to a typical exterior stain, which make them stronger. I recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until lately, the major problem with exterior 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 require a different sealer overcoat, although you can include one (such as Olympic Water Guard) if you think extra protection is required to battle 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 aren't a good deal. Advertisements for silicon stains and deck sealers often show beaded up water on a deck, and many people are fooled into thinking that this is actually the indication of a successful coating. However, silicone deteriorates quickly, usually in a matter of months, producing a discolored, waxy coat that is clearly 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, nonetheless they are too soft to be utilized on your deck. Removing these coatings can take gallons of wood cleaner and a significant amount of work.
Water based outside stains, such as Sherwin Williams Woodscapes, combine the advantages of oil-based and latex coatings. They run and drip significantly less than oil based stain, and dry out faster, enabling two coatings the same day. Water based stains possess the resilience and versatility of your latex stain, giving them stamina. They're a great choice for most applications. But bear in mind that clearing up water based stains takes 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 supplier for specific cleaning guidelines for water based stains, and read the label.
When In Doubt, Ask Questions
If you still have questions about which paint or stain to make use of, don't hesitate to ask people in the know. An experienced, knowledgeable salesperson can answer any questions it's likely you have. Look for a paint store with staff having at least a decade of experience in the business. Ask them what has worked best for your particular application and ask to see a spec sheet on the product in question.
The answers you get will depend on whom you ask. A paint store will attempt to sell you one their own products, after all, that is why they're in business. Painting contractors may not be impartial, either. They have to sell their knowledge. I get lots of cell phone calls from people wanting assistance with their painting problems. Most painters, including myself, don't mind giving an hour of our time, but if you need comprehensive answers, consider finding a contractor for a professional analysis. Rates vary, but I charge about $60 for a written and oral evaluation, depending on driving time involved. A paid analysis will tell you whether you should paint, stain, or re-side, as well as which finish might be best for your project. Each painting job has unique conditions that warrant specific answers.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
