Q: Last year, I built a brick planter against the front wall of my home. Now that I’m selling the property, the termite inspector says there should be an air space between the planter and the building to prevent moisture damage in the wall. This seems unnecessary because I installed sheet metal behind the planter for the very purpose of preventing moisture problems. I explained this to the inspector, but he says the air space is still required. Can you please settle this matter? What are the requirements for building an attached planter?
A: When you installed sheet metal flashing behind your planter, you were only partially in compliance with applicable codes. Planters that are installed against a wood frame building must have flashing, but requirements also include a 2-inch air space between the planter and the building. Sheet metal must be used in conjunction with, not in lieu of, this air space. Without the flashing, a 6-inch separation from the building would be required.
The use of flashing, without an air space, presents two potential problems:
• Sheet metal flashing between the planter and the house is a temporary barrier only. Continued moisture exposure to the sheet metal leads to eventual rust damage. Thereafter, moisture from the planter would have a direct path to the wood-frame wall;
• Even when the sheet metal is intact, it can only prevent moisture penetration from the planter itself. The upper edge of the flashing remains exposed to water intrusion from direct rainfall or irrigation. Any water that drains between the flashing and the wall surface can promote fungus damage and mold.