Insulation in Eureka, Missouri

Insulation and air sealing in Eureka

Eureka runs to about 11 square miles and roughly 11,646 people. It sits about 25 miles southwest of downtown St. Louis. That is roughly 4,805 housing units. The community dates back to 1954. We cover ZIP code 63025.

Our job history shows nothing in Eureka so far. Plenty of sites will show you a number here anyway.

The housing stock in Eureka

The typical home in Eureka dates to around the late-1990s. Houses of this vintage usually got batts or blown fiber at whatever the standard of the day was, which is well short of what is recommended now. Most are one top-up away from being right.

The city also annexed the 549-home Windswept Farms subdivision in 2019, adding a newer construction cohort.

That includes Windswept Farms. Housing age and construction shift across Eureka, sometimes by decades within a few streets, which is why we look in the attic before quoting rather than after.

Eureka was hit by major Meramec River flooding in December 2015 (100+ boat rescues) and April 2017 (roughly 48 inches of water damage to a church, damage to Eureka High School's gym floor); researchers linked the losses partly to outdated FEMA flood-frequency estimates for the area.

Eureka homes in the Census numbers

The Census Bureau estimates 4,805 homes in Eureka. 143 of them (3%) went up before 1940 — 27th of 44 places on this site for pre-1940 housing. The 1990s were the busiest decade, adding 1,009 of today's homes (21%); 22% predate 1980 and 47% were built in 2000 or later. For St. Louis County as a whole the pre-1940 share is 10%, so Eureka sits below it.

Of 4,690 occupied homes, 62% heat with utility gas and 35% with electricity; another 2% burn propane or other tank gas. Electric heat here is more common than across the county (23%), and ranks 21st of 44 on this site. That is why the assessment asks how the house is heated: the fuel and the name on the utility bill decide which program, if any, can pay toward the work.

79% of occupied homes are owner-occupied and 82% of all homes are single-family detached houses. On a housing mix like this, the likely starting points are air sealing on newer houses that already have depth and an energy assessment before deciding what to fix first.

4,805 homes, Census ACS 2020–2024 (B25034, B25040, B25003); 4,690 occupied.

Sealing comes first in Eureka

1,474 of Eureka's 4,805 homes (31%) were built in the 1980s and 1990s. The gaps in houses of that age are the parts nobody sealed: batts stuffed into the rim joist, bare spots over cathedral and tray ceilings, soffit vents buried with no baffles, can lights punched through the ceiling plane. A top-up plus a day of sealing usually covers it.

What the energy code requires in Eureka

Eureka enforces the 2018 IRC Chapter 11 (Energy Efficiency). Division 2, Adoption of Codes, of the Eureka city code adopts the International Building Code 2018 Edition for commercial and industrial buildings, the International Residential Code 2018 Edition for one- and two-family dwellings, and the International Swimming Pool and Spa Code 2018 Edition, all by Ordinance No. 2476 dated 2-19-2019. It also adopts the St. Louis County existing building, mechanical, plumbing, electrical and explosives codes. No International Energy Conservation Code appears in the list, and the ordinance shows no deletion or amendment of Chapter 11, Energy Efficiency, of the 2018 IRC, so the residential energy requirements are the ones in that chapter. The city's Building Department page states the adopted codes are the 2018 IBC as amended, 2018 IRC as amended and 2018 International Swimming Pool and Spa Code as amended.

For new work, the attic number under that edition is R-49, with walls at R-20, or R-13 plus R-5 continuous. Set that against the Department of Energy, which recommends R60 for an uninsulated attic in this climate zone and R49 for one that already has a few inches.

Chapter 11 of the 2018 IRC carries the same envelope requirements as Table R402.1.2 of the 2018 IECC. For climate zone 4 except marine that is ceiling R-49 and wood frame wall R-20 or R-13+5, per the PNNL Building America Solution Center IECC and IRC insulation table and NAIMA's 2018 IECC climate zone 4 summary.

Do you need a permit to insulate here?

There is no published answer for Eureka. Neither the permit-required list nor the exemption list mentions insulation or air sealing at all. The Building Department page says permits are needed for new construction, remodeling or enlargement, and gives new homes, decks, swimming pools, interior finishes, fences and water heater installations as examples. Insulation, air sealing and weatherization are not named. The city fee schedule in the code has no line for insulation, weatherization or energy work; building permit fees are $50 for construction valued from $500 to $25,000 plus $3.00 per additional thousand, and mechanical permits are $50. That silence is not permission and it is not a prohibition. We settle it with a phone call before the crew is scheduled.

The city publishes no insulation contractor registration or licensing requirement. Its code notes that mechanical work requires a license from the St. Louis County Board of Mechanical Examiners.

Permits and inspections in Eureka

The published number is 636-938-5233. The department page is here.

Permitting is on us, not on you.

Rebates an Eureka homeowner can actually use

Most Eureka addresses are Ameren Missouri electric customers, and Ameren Missouri pays toward insulation through Pay As You Save: $0.20 per square foot on the attic and $0.06 per square foot on air sealing in the 2026 program year, with the rest of the cost recovered through the electric bill. The conditions: an attic going from R-20 or below to at least R-38, air sealing that cuts measured leakage by 20 percent, and twelve months in the home. CommunitySavers can include attic insulation at no charge for income-eligible households. Income-qualified households can apply to Community Action Agency of St. Louis County (CAASTLC) (314-863-0015) for free weatherization instead. The St. Louis County page and the rebate guide carry the full rules.

Nearby

Eureka borders Wildwood and Pacific. These are the ones we also cover, each with its own energy code and permit rule:

Elsewhere in St. Louis County we also cover:

How Eureka compares with its neighbors

Missouri sets none of this at state level. Across the 7 places in this table there are 3 different adopted editions (2015 IECC, 2018 IRC ch. 11 and 2024 IECC), and 2 of the 7 publish a permit rule for insulation.

All 21 St. Louis County jurisdictions side by side →

Common questions about insulation in Eureka

Code and permit facts checked September 10, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: ecode360.com (2, 3) · eureka.mo.us (2) · data.mo.gov · basc.pnnl.gov · insulationinstitute.org · en.wikipedia.org · bestplaces.net · ameren.com (2, 3, 4) · energystar.gov · data.census.gov. These change; confirm with the building department at 636-938-5233 or your electric utility first.