Rapid growth means young housing stock, but humidity doesn't care
Because Westfield's population roughly tripled between the 2000 and 2010 census counts, most of its housing stock is young by Carmel-area standards — but central Indiana's humid summers affect a 2005-built subdivision home around Grand Park Sports Campus just as much as an older farmhouse near the 1834 Quaker settlement core, especially where builder-grade attic or crawlspace ventilation was undersized for the home's size.
Older Westfield homes and a longer moisture history
The relatively small stock of homes built before Westfield's 2000s growth boom, closer to the town's 1848 incorporation-era core, have had more decades of exposure to seasonal humidity and any past water intrusion, so a mold assessment there often needs to look further back than the home's most recent renovation.