Airless Sprayer vs. Brush and Roll
The technique a painter uses is as important as the products he applies to your home. There has been a lot of debate about what the superior technique is when painting an exterior. Using an airless sprayer and rollers and brushes have their advantages and disadvantages.
The roll and brush advocates will tell you that they are working the paint into the wood crevasses, grain and natural pits of the wood that are missed by a paint sprayer. When you brush and roll you do not have to deal with “over-spray” from a sprayer so you do not have to cover everything with plastic. They also accuse the painters who use sprayers of thinning or watering down their paint when they use an airless sprayers so the sprayer will work properly. They also accuse the sprayer of applying less paint.
The airless spray advocates say that spraying takes less time and will apply more paint to the areas needed without having to apply a second coat. They claim to achieve cleaner lines where two colors meet because they use tape and plastic to make sure the paint is applied only to the areas needed. They accuse the brush and roll only painters of using less paint because they are spreading the paint out over a larger surface area and not applying two coats needed for full coverage. They accuse the roll and brush advocates of using undocumented workers because of the additional labor required in brushing.
There is a lot of red state blue state fighting between the two factions. The truth is the substrate is the real variable to consider when choosing a technique to apply paint on an exterior. This construction material (siding and trim) can be either smooth or rough or something in between.
Siding Material (substrate) is the Real Consideration
There are several different types of siding: Vinyl, Aluminum, Cedar, Fiber Cement, Steel, Brick, Stucco, Stone, Log Siding, Wood and Wood composite. Wood or a wood composite siding is still the most used in North America. Even though it is loosing market share to artificial siding materials most residential neighborhoods that have been built in the last 20 years have wood composite siding.
The man-made wood siding is generally smooth to the touch while still displaying a natural wood grain. Because of the way this product is manufactured it does not have crevasses, pits or groves that would allow moisture to penetrate the material.
For any smooth surface spraying is the best option. An even smooth coat can be applied by a professional painter that does not and should not require being back-brushed. Back brushing or rolling will actually leave streaks and stempling (small bumps) where the finish should be smooth. Modern airless sprayers do not require the paint to be thinned because of the spray tip size and pressure options available. If your painter is thinning the paint he is essentially changing the chemical composition of the product and is reducing its life and effectiveness.
The way an airless paint sprayer is used is also important. The painter should be be applying the paint with even smooth strokes at a consistent steady rate overlapping each pass. A painter who flourishes the paint sprayer nozzle is applying a thin coat that will not cover adequately.
Natural Rough Surfaces
Another very popular siding is cedar. This is a natural product that enhances the beauty of many homes. However this material is typically a rough-sawn product and therefore has deep grain, groves, pits and crevasses and will split and curl when aging.
The best technique here is to use an airless sprayer to apply the paint/stain and then back brush or roll because the paint/stain needs to be worked into the product. Natural material absorbs and holds moister unevenly so just spraying an even coat over the top of cedar will result in an uneven finish. Problems like flaking and sheeting will appear when too much product is applied to natural materials. When the new stain is applied over old and does not penetrate the surface it can peal off from lack of adhesion. If the new stain/paint is worked (brushed or rolled) over the old the product can be moved to where the cedar will absorb it more evenly. If a roll and back-brush technique is used without spraying the initial coat, the painter is not applying enough product to get the coverage necessary for adequate coverage and will need to apply a second coat.
The Best Method
Beware of any painter who tells you they use only one method of applying paint. They are not considering the substrate they will be working with. In Parker and Colorado in general I have found that spraying the smooth wood composite siding works best. Rolling and brushing two coats on the natural rough trim boards is the best technique for about 90% of the homes we paint. We will spray and back-brush rough cedar siding for outstanding results. You get the best of both worlds on the siding and trim substrate. Be sure to ask your painter what technique he uses and why.
Please give us a call at 720-231-2344 or email us firstname.lastname@example.org to help you with your next painting project.