29 Nov Exterior Log Home Surface Care
Understanding exterior log finish products will serve to help you understand when and what type of exterior care a log home may require.
Oil based stains were once common, inexpensive, and easy to apply but oil wicks into the wood over time and needed to be reapplied every 3-5 years. Oil has fallen out of favor more recently due to EPA regulations limiting VOC content, and currently the trend is toward acrylic finishes designed to both meet VOC regulations and provide surface protection without frequent product re-application.
Acrylic finishes use water as a carrier agent to deliver the acrylic stain to the wood. These finishes meet VOC rules and function like “Gore-Tex” to repel water. Acrylics are typically applied in three layers: two stain coats followed by an acrylic topcoat. Advanced acrylics feature metallic (trans-oxide) pigment comprised of microscopic sized particles of titanium or transparent iron oxide provide superior UV and sun protection.
Film forming finishes include paints, varnishes, and some oil-based finishes. They are among the least popular finishes because typically they are not hydroscopic (they do not “breathe”). Logs acclimate to the moisture content of their environment constantly and if moisture can not pass easily through the finish it will “push” on the finish causing it to flake or peel.
Removing a failed finish is necessary before applying a new one. Failure to do so is like spray painting over rust: the improper substrate will not hold the new finish long term. Most oil-based products can be removed using a chemical stripper intended to emulsify the old finish for removal by water. This is much different than using a pressure washer as you would a sandblaster and destroying the wood, as it is done with specialized equipment and at low pressure. Finishes that don’t respond to chemical stripping can be media blasted (a process similar to sandblasting, except that sand is not used for safety reasons). The most common media material presently being used is recycled crushed glass (which resembles fine sand in texture and size).
Properly prepared surfaces finished with the newest log home finish coatings can eliminate much of the tedious refinishing many people associate with log home living.