What CostFiled is
CostFiled publishes home-renovation cost ranges computed from public building-permit records, instead of contractor-submitted surveys or self-reported estimates. The goal is a number you can trace back to a real filing, not a marketing average.
Methodology
For US cities, every published range is computed directly from declared valuations on municipal building-permit filings, published through each city's own open-data portal. The pipeline keeps only residential filings with a declared cost between $1,000 and $2,000,000 (to exclude nominal placeholder values and commercial-scale outliers), and only publishes a city/project combination once at least 30 qualifying filings exist. We report the 25th percentile, median and 75th percentile — never a single-point "average" — because declared costs vary legitimately with size, specification and site conditions.
Declared values are what applicants file with the permitting authority, not final contractor invoices, so treat every range as planning guidance and a sanity-check against the quotes you receive — not a quote itself.
UK planning and building-control records rarely include cost valuations, so UK pages currently show indicative market ranges assembled from industry benchmarks rather than filings. These are clearly labelled as indicative wherever they appear, and are kept out of search results until a real UK permit-data pipeline is built.
Who runs this
CostFiled is an independent, single-operator publication. It is not affiliated with any city government, permitting authority, or contractor.
Contact
Questions, corrections, or a city/project you'd like to see covered: support@aishortsystem.com.