Stone column Box

I have inspected several houses where a plywood box was built around the base of the columns and covered with adhered stone. The bottoms of these columns were at or below ground level causing water damage to the plywood and creating an environment for termites. The bottom IMO should be at least 4" above the ground. Be sure to check the bottoms, if possible.


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Great info to use, Randy!

How do you verify it’s plywood and not CMU? what if the plywood is pressure treated?

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Dig down and see if there is a footing for CMU. I haven’t seen plywood treated for ground contact.

Thanks Randy!

Ground contact plywood:

I have used this stuff bottom first 2 feet from sill plates around exterior walls of my house. I had a lot of termite/rot damage from previous homeowner.

If you read the fine print in their warranty they exclude the use as I have shown in the photo.

Here is a sample of their verbiage for exclusions:

• With the exclusion of fence pickets, applications which are within six inches of the ground (final grade after landscaping) and supported on permeable building materials such as treated wood or concrete;
• Applications which are constructed so as not to allow air to circulate underneath the construction and between decking boards;
• Applications where there is a reasonable expectation that soil, vegetation, leaf litter, or other debris may build up and remain in contact with the product.


If you look closely, those exclusions are listed under “above ground warranty exclusions” which applies to “above ground” PT lumber only. The ground contact (GC) PT is a different animal, as you know :slight_smile: The whole purpose of GC PT is to be installed in areas of ground contact (soil) or conditions which could simulate ground contact. I would be careful if and how I call it out if it is indeed a GC PT plywood, even though it won’t last as long as CMU.

Here ya go Randy:

Come on guys. Anything not visible/accessible becomes a limitation.
What about column footing? Brick/stone masonry wood clearance?

Observation: Columns. Inadequate wood/brick/stone masonry clearance. Location: Front entrance overhang. *Note: No adverse conditions observed the day of the inspection; if there where none.
Columns consist of 2 sections. A: Lower masonry section. B: Upper column. Board lumber. Unknown species.
Lower column. Materials. Flag stone. Suspect-plywood. Column Too close to grade. No flagstone plywood clearance.
Upper column. Board lumber. Unknown wood species.
Base/footing. CMU. No capillary break.
Recommendations. A licensed general contractor:
1: Insure proper bottom clearance of the lower masonry column to prevent moisture wicking and termite pathway. 2: Provide a capillary break under the upper column footing. 3: Insure all materials are caulked and sealed to impede moisture intrusion.
Limitations. Soil. Materials behind masonry. Covered Column Features.