Sand or Cob Blasting vs. Power Washing
June 3, 2010
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Greetings!
We hope you are enjoying the beginning of summer. Many of you were at your cabins this past weekend and you may have noticed some signs of issues with your logs. As promised, each month this summer we will choose a topic about log home maintenance to highlight.
About 25% of the work that we do is "finish removal" or blasting. Power washing is also a very popular method of doing this type of work on log homes. This month's featured topic: Why power washing is not a good choice for removing finish from log homes.
Sand or cob blasting has a number of advantages over power washing.
The process of removing a finish from the logs is, simply put, a matter
of throwing something at the building at a certain velocity (or
pressure) that is sufficient enough to take off the finish while causing
as little trauma as possible to the logs. Blasting is a dry process. When dry, the surface of the finished logs is
somewhat brittle. When the dry logs are hit with the sand or cob media,
the brittle finish is quickly and efficiently removed leaving the logs
relatively smooth. Power washing is a wet process,
which relies on water as the media to remove the finish instead of sand
or cob. As water is applied to wood, it expands and more importantly,
it softens the fibers of the wood. These soft fibers are then exposed to
1800 to 3000 psi of water. This process can cause the fibers to break
length-wise and can result in what is referred to as the "fuzz effect".
This basically looks like the log home or cabin has grown 1/2" long
hairs.
Introducing more moisture to the wood is exactly the opposite of what
log homes need because water is the enemy of a log building. See Why Do Logs Rot
for more information.
Another disadvantage of power washing is that the
high-pressure water used in the process makes its way into parts of the
log building that have never seen moisture before. This can cause a
number of additional problems including:
- The feces from rodents (bats, mice or rats) gets washed
out onto the surface of the logs and can cause staining - The insulation between the logs can get wet and cause
mold and mildew to form - The subsequent quick-drying of the outer log surface
can cause additional checking (cracking) to occur in the logs, which can
lead to further problems such as rot.
 While it is
almost impossible to keep a log home from leaking inside to some degree
when power washing or blasting, the
problem with power washing is again, the use of water. Not only are you
wetting the logs but this water can make its way into the home and
stain or ruin interior finishes, floors and home furnishings. Check
out the photo to the right. Here you can see that water leaked inside
the building and caused major staining of the interior logs. The sand and cob blasting material may
come through the walls to some degree, but the dust is dry. Sometimes if
the dust is significant, we will drape the interior walls with plastic
in order to allow the dust to fall to the floor as it comes
inside. This minimizes the dust coming into the home and makes it
easier to clean up with a vacuum or a broom. Check out our video on sandblasting.
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 A Frequently Asked Question
Q: I see rot at the bottoms of my log posts. What can be done to prevent or fix this problem?
A: It is very important to provide adequate airflow under and around your log columns or posts. Cedar logs are the most rot resistant wood to use where the logs are directly out in the weather. We use a combination of tactics to prevent decay in these exposed and vulnerable posts. First, we use a stand off base to get airflow around the base of the post. We use borates on particularly rot-susceptible areas of the posts to further insure against decay. Read More...
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Contact Us
Call our toll-free number 877-378-4403
or email us at info@restorelogs.com.
We look forward to hearing from you!
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