Attic insulation, air sealing, crawl spaces and walls for homes in University City — starting with a free assessment that measures the R-value you actually have. University City enforces the 2018 IECC, which sets R-49 for a new attic.
University City runs to about 5.9 square miles and roughly 35,065 people. It sits about 6 miles west of downtown St. Louis. Around 17,841 housing units sit inside those boundaries. The community dates back to 1906.
No completed job in University City is logged in our records yet, and this page will say so until one is.
The typical home in University City dates to around the late-1940s. Houses built before the war generally went up with nothing in the walls at all and whatever went into the attic afterwards. Anything up there was added later, usually in a hurry.
The city's population peaked at 51,249 in 1960 and declined afterward. Its southern half retains streetcar-suburb-era architecture from the early 20th century along Delmar Boulevard, while post-WWII development dominates the northern sections.
That includes Delmar Loop. Housing age and construction shift across University City, sometimes by decades within a few streets, which is why we look in the attic before quoting rather than after.
Incorporated in 1906 by Edward Gardner Lewis. The Delmar Loop–Parkview Gardens Historic District (NRHP-listed 1984) covers 84 acres and 289 contributing buildings, construction of which began in 1911 in Bungalow/Craftsman, Tudor Revival, and Georgian Revival styles.
The Census Bureau estimates 17,841 homes in University City. 6,797 of them (38%) went up before 1940 — the 3rd-highest share of pre-1940 housing among the 44 places on this site. More of today's homes date from before 1940 than from any single decade since, and 85% predate 1980. For St. Louis County as a whole the pre-1940 share is 10%, so University City sits above it.
Of 15,782 occupied homes, 78% heat with utility gas and 19% with electricity; another 2% burn propane or other tank gas. Electric heat here is less common than across the county (23%), and ranks 40th of 44 on this site. Which utility program can contribute depends on the heating fuel and on who sends the bill, so that is the first thing an assessment pins down.
56% of occupied homes are owner-occupied and 61% of all homes are single-family detached houses. On a housing mix like this, the likely starting points are wall insulation for walls built empty and a vermiculite check before anything is disturbed.
| Built | Homes | Share | |
|---|---|---|---|
| Before 1940 | 6,797 | 38% | |
| 1940s | 2,259 | 13% | |
| 1950s | 3,794 | 21% | |
| 1960s | 1,335 | 7% | |
| 1970s | 962 | 5% | |
| 1980s | 798 | 4% | |
| 1990s | 844 | 5% | |
| 2000s | 405 | 2% | |
| 2010s | 539 | 3% | |
| 2020 or later | 108 | 1% |
17,841 homes, Census ACS 2020–2024 (B25034, B25040, B25003); 15,782 occupied.
9,056 of University City's 17,841 homes (51%) went up before 1950. In houses that old the air leaves before any insulation can slow it: balloon-framed bays open from the sill to the attic, open chases behind knee walls, plaster-and-lath ceilings leaking at every fixture. Those get blocked and sealed first. Two checks come before any quote on a house this old: loose gray-brown flakes in the attic, and cloth-covered wiring on ceramic knobs.
University City enforces the 2018 IECC. University City's Energy Conservation Code article adopts the International Energy Conservation Code, 2018 Edition. The article traces to Ordinance No. 6937, Section 1, of October 28, 2013 and was amended to the 2018 edition by Ordinance No. 7139 of January 25, 2021. The amendments are administrative: they set the code's title and enforcing agency (C101), align third-party inspection procedures with the local building code (C105), address stop work order violations (C108) and route appeals through the local Building Code (C109). The city's residential code article adopts the International Residential Code, 2018 Edition, by Ordinance No. 6933, Section 1, of October 28, 2013 as amended by Ordinance No. 7139.
That edition sets R-49 for the attic in new work, and R-20, or R-13 cavity plus R-5 continuous for walls. The Department of Energy's recommendation for this climate zone runs higher: R60 for an attic with nothing in it, R49 where a few inches are already down.
2018 IECC Table R402.1.2, climate zone 4 (except marine), as reproduced in the U.S. Department of Energy / PNNL Building America Solution Center comparison of 2009-2021 IECC and IRC minimum insulation requirements.
Nothing University City publishes settles this. Its permit lists name the work types it cares about, and insulation is not among them in either direction. Nothing on the pages that did load names insulation, air sealing or weatherization as requiring or not requiring a permit. So we ask the department directly before the first day on site, and whatever comes back, pulling it is our job rather than yours.
University City issues electrical permits only to electrical contractors licensed by St. Louis County, and tells residents they can verify a contractor's license by calling the Community Development Department. Nothing published states that an insulation contractor must be licensed or registered, with either the city or the county.
We could not find a published number for the building department, so this page does not print one. The department page is here.
Permitting is on us, not on you.
Most University City 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. It counts only when the attic is at R-20 or below beforehand and R-38 or more afterward, when air sealing cuts measured leakage by 20 percent, and when the household has lived there for the past year; for income-eligible households, CommunitySavers can include attic insulation at no charge. Income-qualified households can apply to Community Action Agency of St. Louis County (CAASTLC) (314-863-0015) for free weatherization instead. For every condition attached, see the St. Louis County page or the rebate guide.
Every layer of an insulated attic, explained
University City borders St. Louis City, Olivette, Ladue and Northmoor. These are the ones we also cover, each with its own energy code and permit rule:
Elsewhere in St. Louis County we also cover:
Missouri sets none of this at state level. Across the 7 places in this table there are 4 different adopted editions (2015 IECC, 2018 IECC, 2021 IECC and 2024 IECC), and 1 of the 7 publishes a permit rule for insulation.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| University City | 2018 IECC | R-49 | Not published | — |
| St. Louis City | 2018 IECC | R-49 | Not published | 314-622-3313 |
| Affton | 2015 IECC | R-49 | Not for an attic top-up | 314-615-5184 |
| Ballwin | Not published | — | Not published | 636-227-2129 |
| Brentwood | 2024 IECC | R-49 | Not published | 314-963-8602 |
| Chesterfield | Not published | — | Not published | 636-537-4000 |
| Clayton | 2021 IECC | R-60 | Not published | 314-290-8463 |
All 21 St. Louis County jurisdictions side by side →
University City enforces the 2018 IECC, which sets R-49 for an attic in new work. Whether it reaches a retrofit of an existing house is not published.
Not on paper: University City names neither a permit nor an exemption for insulation, so one call to the department settles it first.
For most Ameren Missouri customers, Pay As You Save: $0.20 per square foot on an attic starting at R-20 or lower and $0.06 per square foot on air sealing in 2026, the rest repaid on the bill. The federal 25C credit ended for work placed in service after December 31, 2025.
The typical home in University City dates to around the late-1940s; the Census Bureau's 2020-2024 median year built is 1949. Of its 17,841 homes, 38% went up before 1940 and 6% in 2000 or later. That is a median across the whole place, so your own house may be older or newer.
Code and permit facts checked September 10, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: ecode360.com (2, 3, 4) · ucitymo.org (2, 3) · basc.pnnl.gov · en.wikipedia.org (2) · city-data.com · ameren.com (2, 3, 4) · energystar.gov · data.census.gov. These change; confirm with the building department or your electric utility first.
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