There is extensive wildfire research that statistically analyzes the different factors correlated with ignition or survival of a structure in a wildfire.
This diagram below illustrates the results of a 2021 analysis of the Paradise (Camp) Fire of correlating the ignition of a structure with different factors around it: a high number means that a structure is less likely to survive.
For instance, in order, in this analysis, the factors most likely to be correlated with ignition of a structure are:
- non-class-A wood shake roof
- lack of defensive space (0-5ft CA regulations, 5-30 ft CA regulations)
- unscreened vents
- single-pane windows
- wood decks or porches
- combustible fences
But this analysis focuses on a single small set of factors. When considering multiple such analyses, the following factors bring particular survival value as well as excellent cost effectiveness:
- screening vents with at most 1/8" metal screens (or smaller)
- screening gutters with at most 1/8" metal screens (or smaller)
- enclosing low decks or stairs with at most 1/8" metal screens (or smaller)
- enclosing the lower side of eaves with noncombustible materials
- establishing a vertical noncombustible zone of 6 inches between the ground and the siding, or with posts supporting decks, stairs or porches
- weatherstripping the bottom and sides of garage doors
BFD’s page on home hardening provides excellent data and suggestions. Have a look!