Function
Exterior stain protects wood to varying degrees, and can also help it keep its natural color, despite different weather conditions. Both oil and latex exterior stains may darken wood, tint its color or make it appear evenly weathered.
Latex Stain Types
Latex stains come in either semitransparent or opaque (solid) varieties, according to the U.S. Forest Service. Semitransparent latex stain has less pigment than opaque latex stain, but both coat the wood with some color. Opaque latex stains are thicker than semitransparent latex stains, according to the U.S. Forest Service.
Oil Stain Types
Oil-based exterior stains also come in semitransparent (penetrating) and opaque varieties. Opaque oil-based stains coat wood with a layer of stain and pigment, according to the U.S. Forest Service. Penetrating (semitransparent) oil stains, however, soak into the wood and do not leave a coating over the surface of the wood.
Latex Stain Benefits
Latex stains coat the surface of wood, providing some protection from the elements. Opaque latex stains provide a thick coat over the surface of the wood and a decent amount of protection, while semitransparent latex stains tend to flake with weathering. Latex stains are relatively flexible, which allow them to contract and expand with varying weather conditions to prevent cracking, according to the U.S. Forest Service. Both stains provide the benefit of allowing painters a wide range of colors to tint the wood.
Oil Stain Benefits
Penetrating oil stains benefit wood by soaking into it and changing its color. Since the stain soaks into the wood rather than coating it, it does not chip or flake off like other types of stain can. According to the University of Minnesota, penetrating oil stains allow a natural look, while protecting the wood, increasing its life and preventing it from becoming silvery with weathering. They can alter the color of the wood slightly or a lot, but they allow the natural wood-grain and texture to show through. This type of stain is also easy to reapply if it fades anywhere.
Opaque oil-based stains protect wood with a strong surface layer of stain, while allowing painters to add a large amount of color to the wood.
Oil Stain Drawbacks
Opaque oil-based stains are less flexible than latex stains, so their protective layer can crack more easily, according to the U.S. Forest Service. Wood needs several coats of opaque oil-based stains to build up a thick enough layer for strong weather protection. They also coat the wood and cover up lots of the natural wood grain.
Semitransparent oil-based stains can only go on top of unfinished and unstained wood, except for on top of other semitransparent oil stains, according to the U.S. Forest Service.
Latex Stain Drawbacks
Latex stains coat wood in a protective layer, which covers up lots of the natural wood grain, according to the U.S. Forest Service. Semitransparent latex stains also chip relatively easily, which makes them an unimpressive choice for wood that goes through a lot of wear and tear, such as wooden walkways.
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