Home / What insurers look for / The bottom 6 inches of the walls and flashing
Do I need flashing or noncombustible material on the bottom 6 inches of my walls?
Insurers ask for noncombustible material on the bottom 6 inches of every exterior wall. IBHS Essential requires it. It does not have to be flashing. It is not in the state draft.
The state Zone 0 rule is not law yet. Insurers and IBHS already use their own lists.
What to check
Walk every outside wall. Look at the lowest 6 inches above the ground.
Look again above any deck or patio that touches the wall.
Note wood siding, trim or corners in that band.
Check deck posts and stair bases too.
Ask your insurer what it accepts before you spend money.
What each list says
The lists do not always agree. Here is what each one says about this.
- IBHS Essential
At least 6 inches of noncombustible material applied vertically at the base of all exterior walls. It is measured from the ground up to the nearest horizontal surface, such as a deck or patio. Combustible deck posts need the same covering (sections 2.1.4 and 2.1.5).
- State discount list
Noncombustible material 6 inches at the bottom of walls.
- FAIR Plan
6 inches at the bottom of all exterior walls made of noncombustible material.
- San Diego
A voluntary step: a minimum 6-inch metal flashing, applied vertically on the exterior of the wall where a deck meets it.
- State draft
The August 2026 draft, as we read it, sets no standard for this.
- For the base of posts, supporting walls and stairs under a deck, IBHS names fiber cement, metal flashing, masonry veneer and stucco.
Sources
- IBHS Wildfire Prepared Home Technical Standard (2025 edition)
- Safer from Wildfires regulation: frequently asked questions, California Department of Insurance, September 2026
- Discounts for dwelling fire and commercial policies, California FAIR Plan, November 15, 2025
- Zone 0 guidelines for existing structures, City of San Diego, April 2026