California Remodel Cost vs. Value › Projects
Caissonix report · 2026 · 13 California cities
Does a Seismic Retrofit Add Value in California?
A study of 217 older California houses (Porter, Alhumaidi and Reed, Natural Hazards Review, 2022) found retrofitted pre-1940 homes sold for about 17% more in 2020, while the effect for 1940–1959 homes was about 1% and weak. The sample is small, so we show it as context only.
Our estimator does not price this project yet, so the cost side is blank for now.
Not an appraisal, a broker price opinion or a prediction of a sale price. Costs are budget estimates, not a bid, appraisal, or insurance claim valuation. Pilot.
The project we priced
Seismic retrofit (bolt and brace). Bolt the house to its foundation and brace cripple walls on an older raised-foundation home. Not priced by our engine yet.
Same scope in every city. Your own home, size and finish choices will differ.
Resale value: what we can verify
217 pre-1960 California houses (29 retrofitted): 17% higher price for retrofitted pre-1940 homes in 2020; about 1% and weak for 1940-1959 homes. Small sample.
Source: Porter, Alhumaidi and Reed, "Seismic Retrofit Added 17% to the Resale Value of Older California Houses", Natural Hazards Review (2022). https://doi.org/10.1061/(ASCE)NH.1527-6996.0000579
Shown as outside research context, with credit. It is not a Caissonix figure and is not applied to any city.
Value figures for this project are coming. Here is how we will get them, without borrowing anyone else's survey numbers:
- Public sales and permit records: compare homes that sold after a permitted project with similar homes that did not, county by county.
- A 2027 Caissonix survey of California real estate agents and appraisers, by region.
Until then, this page shows cost only. How we measure value.
Questions
Does a Seismic Retrofit Add Value in California?
A study of 217 older California houses (Porter, Alhumaidi and Reed, Natural Hazards Review, 2022) found retrofitted pre-1940 homes sold for about 17% more in 2020, while the effect for 1940–1959 homes was about 1% and weak. The sample is small, so we show it as context only.
Is this an appraisal?
No. It is an informational report: budget cost estimates plus the resale value evidence we can verify from public records and published studies. It is not an appraisal, a broker price opinion or a prediction of what your home will sell for. For a valuation, ask a licensed appraiser or a local real estate professional.
Caissonix California Remodel Cost vs. Value, 2026 pilot edition. Cost figures computed 2026-10-31 from engine 0.10.0, price book 2026-10-31.1. Not an appraisal, a broker price opinion or a prediction of a sale price. Costs are budget estimates, not a bid, appraisal, or insurance claim valuation. Get licensed contractor bids before you decide.