Wood Post Decay

Wood Post Decay

In warmer climates, many homes have large front porches for people to sit and relax.  This is certainly true throughout the South.   The “winter” is short, and the summer seems to last forever.  So, the front porch is a nice place to relax, visit with family and neighbors, and enjoy the view of a freshly cut lawn.

The front porch is similar to a front cover of a book.  For many, they make their decision to proceed to the inside based on what they see on the outside.  This is why real estate agents often suggest that homeowners that are attempting to sell their house spend some time to improve the curb appeal of their home.  For most homes this may involve a new coat of paint and some landscape improvements.

However, the curb appeal of some homes is decreased due to advanced wood decay.  I was recently walking with my son and dog in my neighborhood and noticed a house for sale that had advanced wood decay on each post that was supporting the front porch. 

The posts were 6×6 and the porch was brick.  The posts had been improperly installed due to the absence of a base plate.  I have similar posts at my house between the carport and the back porch.  A few years ago, I noticed early decay at the base of some of my posts so I used a pneumatic car jack to slightly elevate them and insert base plates.

Another problem is the slope of the porch is incorrect.  The bricks were laid to allow water to pool at the base of each post.  Algae is growing in these areas.  The porch should be sloped so water drains away from the house and does not collect anywhere on the porch. 

I also noticed that the soffit is too small.  The overhang should be at least 2 ft and this appeared to be closer to 1 ft.  Water from the roof needs to be directed away

from the house.  The soil under the overhang is also not sloped away from the porch.

My neighborhood is almost always hot and humid.  So, the posts are getting wet during rain events and then the base cannot dry out until the ponds evaporate.  The moisture content at the base will easily exceed 30% for long durations which allows decay fungi to operate.  The decay fungi become dormant as the post dries but then become active again as the rain returns.

I would replace the posts with preservative-treated posts and use base plates.  If the decay was incipient, early stages, I would suggest inserting boron rods near the base of the posts and elevating the posts using base plates (see picture above).  As the rod slowly dissolves, the moisture in the wood carries the boric acid through the wood fibers by a diffusion gradient to saturate and protect any wet areas. Some rods contain also copper which is an excellent fungicide.  The copper will bond to the boron and diffuse together in the wood.

Meet the Author

Dr. Todd Shupe is the President of Wood Science Consulting, LLC. He is a well-recognized expert on wood forensics, wood preservation, wood decay and degradation, and wood species identification. He has a broad background in new product development, quality management, and marketing and sales in both the public and private sectors. For more information please visit DrToddShupe.com.

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