For any Interior painting job, the question of what paint sheen to use always arises. Of the four basic sheens—flat, satin/eggshell semi-gloss, and gloss—there are advantages and disadvantages to each. When you paint your house exterior, the choice is generally a little more limited, since gloss and semi-gloss paints are rarely used on house siding. But there is still the choice between flat and satin sheens, and since your home's exterior is subjected to major stresses, including rain, snow, UV rays, and physical wear, this question is even more important than for your home's interior.
Understanding Paint Sheens
In a nutshell, the various sheen levels of paint are determined by the ratio of resins and binders to pigment levels in the paint. Paints with a high level of resins/binders create a high-sheen, shiny surface, while those where the pigment levels are high create a less reflective surface. Generally speaking, glossier paints are more durable, while flatter paints are less resilient but cover better.
Although different manufacturers have different terms for describing their paints, in general, there are four different sheen levels to choose from: flat (also called matte), satin (sometimes called eggshell or low-lustre), semi-gloss and gloss (or high-gloss). The ratio of resins/binders to pigments increases with each level.
For large exterior surfaces, glossier paints are usually reserved for trim areas, such as windowsills and doors, as well as surfaces that may be washed frequently. Normally, semi-gloss paint is the best choice for trimwork, since high-gloss paints are so shiny that they highlight imperfections.
For large areas of the home covered by siding, less glossy paints are a better choice. Here, you want to avoid shiny, glossy paints with highly reflective properties that will highlight each bump and imperfection. The choice, then, is between a flat (matte) paint or a satin/eggshell paint.
Flat (Matte) Paints on Exteriors
A flat paint has a non-reflective finish that will feel slightly chalky and rough when you run your hand across it. The finish is quite velvety in appearance, and is initially very attractive, since the lack of reflectiveness hides bumps and gouges. It provides a very contemporary and modern look. However, just as it true on indoor surfaces, flat paints really cannot be washed at all. Cleaning flat-paint surfaces is like trying to wipe down a chalkboard with a dry rag—it smears but does not really come clean. You can scrub flat finish with TSP or water pressure washer, but often the best solution is to lay down another coat of paint. You can expect to repaint more often if you use flat paint.
Pros of flat paint for exterior surfaces:
No overlap marks. Whether brushed or rolled, the paint hides lap marks very well.
Modern, contemporary look when the paint is new.
Hides flaws in the siding surface.
Cons of flat paint for exterior surfaces:
Very difficult, if not impossible to scrub clean.
Surface may become chalky due to weather, requiring more frequent repainting.
Satin (Eggshell) Paints on Exteriors
Satin finishes are relatively low in reflection, which means that they also do a decent job of hiding bumps and imperfections in the siding surface. To the touch, they still have the chalky feel of flat finishes, but with a slight waxy smoothness. The same paint color will appear slightly richer in a satin sheen than it does in a flat sheen. Satin/eggshell finishes can be wiped down or even hosed with water. Because the hint of shine, satin paints have a somewhat more luxurious appearance than flat paints.
Satin paints require a bit more care during application in order to avoid lap marks. As with interior painting, it is important to keep a wet edge during application. It is important that satin paints be thoroughly mixed before application to keep the resins and pigments in uniform ratio throughout the can. Satin paints should be mixed just before every painting session.
Pros of satin paint for exterior surfaces:
Cons of satin paint for exterior surfaces:
Lap marks may be evident when painting.
Sheen can be uneven unless the paint is mixed thoroughly. Have stored paint thoroughly mixed at the store before painting. Boxing the paint (mixing several cans together) can also solve this problem.
Semi-Gloss and Gloss?
In general, reserve the higher gloss levels only for trim and doors—surfaces that get a lot of wear and may need to be frequently scrubbed. The glossier paints are more durable, so they will hold up well on these trim surfaces that take the brunt of the weather. They also may be a logical choice where an exterior will need to be washed frequently, such as in a climate where wind-blown dust is a problem, or in a home where active kids may soil the siding. But the reflective shininess will also spotlight every bump and imperfection, so for most people, they are not a good choice for large areas of siding.
Gloss and semi-gloss paints do, however, produce a richer color, so they are sometimes chosen when an owner wants to make a loud design statement.
All things considered, satin finish is preferable for the exterior of a home. It satisfies basic maintenance points while providing a pleasant appearance that appeals to the widest range of homeowners.
The choice, however, is based on your own situation. Factors to consider:
Will you be painting the house yourself? If so, and if you are less than confident of your skills, then a flat paint may be easier to apply without leaving lap marks. For a skilled DIYer, either flat or satin paint is suitable. If you are hiring a pro, you don't have to worry at all. Professional painters are proficient at laying down all kinds of paint. If they make an error, they are accountable and can be expected to fix the issue.
Do you have children? Bikes get laid against houses, snowballs thrown, and mud splattered. Just as you would choose a wipeable finish for the interior, so too with your exterior. A home that will get this kind of wear should be painted with satin, or perhaps even a semi-gloss paint.
Is your exterior riddled with texture-related blemishes? If so, then flat paint will help hide them.