Insulating a house in Granite City runs on one state energy code, not a local one — here is the R-value it sets, what the city does and does not ask a permit for, the Ameren Illinois discount your address qualifies for, and how old the housing here really is.
Granite City runs to about 21 square miles and roughly 27,549 people. It sits about 6 miles north of downtown St. Louis. That is roughly 13,130 housing units, and the attic above almost all of them is the cheapest thing in the house left to fix. The community dates back to 1896. We cover ZIP code 62040.
Our job history shows nothing in Granite City so far. Plenty of sites will show you a number here anyway.
The typical home in Granite City dates to around the early-1960s. Postwar building here often meant three or four inches of fibreglass and no attempt at air sealing. If nobody has touched it since, that is what is still up there.
Housing includes an early-1900s steel-industry-era layer in neighborhoods like Wilson Park ("turn-of-the-20th-century" homes) and Lincoln Place (first populated around 1906 by immigrant steelworkers, once called "Hungary Hollow"), plus later 20th-century construction.
We work across Granite City rather than one corner of it — Downtown, East Granite, West Granite, North Granite, Nameoki Strip, Bellemore, Wilson Park, Lincoln Place and Granite Park included. Construction and vintage change between them, sometimes by thirty years and a whole different framing method, which decides whether a wall can be dense-packed at all.
A "massive flood" in 1903 covered all of West Granite while the rest of the city stayed relatively dry; the city was protected from the 1993 Great Flood by its levee system.
The postwar housing in Granite City is the metro's biggest and most consistent insulation opportunity. The pattern is remarkably repeatable: three or four inches of fibreglass laid between the ceiling joists, nothing over the top plates, an uninsulated attic hatch, and a bathroom fan venting into the attic instead of through the roof. Ranches and split-levels of this era also give away heat at the garage ceiling and the cantilevered floor over a porch. None of that is a defect — it was normal practice, built to a standard that did not yet exist. It just means the house is running at a fraction of what is recommended for this climate zone now, and the fix is usually a day's work rather than a renovation.
Granite City enforces the Illinois Energy Conservation Code (2024 IECC with Illinois amendments), by state law. The city's building inspection page says Granite City adopted the International Building Code by ordinance in 2005. The Illinois Energy Conservation Code governs residential energy work by statute.
Under that edition the required attic value for new work here is R-49, and walls R-20 + R-5 continuous, or R-13 + R-10 continuous. For comparison, the Department of Energy recommends R60 for an uninsulated attic in this climate zone and R49 where there are already a few inches up there.
Table R402.1.3 of the 2024 IECC as amended for Illinois, climate zone 4. Madison County is in climate zone 4 per the NAIMA IECC compliance guide for Illinois homes.
There is no published answer for Granite City. Neither the permit-required list nor the exemption list mentions insulation or air sealing at all. That is the normal state of affairs across this metro — only a handful of the 45 jurisdictions on this site say anything about it at all. Insulation does not appear in the city's list of permits and applications. The city's page refers generally to permits for home improvement projects but does not name insulation as a permit type. That silence is not permission and it is not a prohibition. We settle it with a phone call before the crew is scheduled.
The published number is 618-452-6218. The department page is here.
Permitting is on us, not on you.
Granite City is on the Illinois side, and the Illinois programme is the more generous of the two by a wide margin. Ameren Illinois publishes flat per-unit discounts applied by the contractor rather than mailed to you as a cheque. On Ameren Illinois' 2026 discount table: $1.10 per square foot for attic insulation and the same for wall insulation, $2.00 per linear foot for rim joist, $3.00 per linear foot for crawl space wall, and $0.70 per cubic foot per minute (CFM) of air leakage reduced for air sealing.
Two conditions decide whether any of that reaches you. Air sealing has to be pre-approved before the work starts — do it first and ask afterwards and the money is gone. And only a registered Ameren Illinois Program Ally can apply the discount at all: a contractor who is not on that list cannot get it for you, whatever they say on the doorstep. Ask which they are before you sign.
Compare that with the Missouri side of the metro, where the same attic gets an on-bill programme paying $0.20 per square foot instead, and only if the attic started at R-20 or below. Same weather, same houses, different utility regulator.
If the household income qualifies, the work can be free rather than discounted. Madison County is served by Madison County Community Development under the Illinois low-income weatherization program — 618-692-8940, details here.
One more, by its absence: the federal 25C credit, which covered 30% of insulation and air sealing up to $1,200 a year, ended for anything placed in service after 31 December 2025. Work finished on or before that date is still claimed on that year's return; nothing done in 2026 is. It should not be in your 2026 price, whoever tells you otherwise — the rebate guide has the detail.
Granite City sits in all eight counties are iecc 2021 climate zone 4 on the same map the Department of Energy uses to write its recommendations, which is why the figure it recommends for an attic here is R60 rather than something borrowed from a national advert. Heating and cooling both matter at this latitude. The energy code and rebate guide sets out the numbers behind it.
Elsewhere in Madison County we also cover:
Illinois sets the residential energy code from Springfield, so these figures agree across the county — what changes here is the permit desk, not the R-value.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| Alton | Illinois state code | R-49 | Not published | 618-463-3500 |
| Collinsville | Illinois state code | R-49 | Not published | 618-346-5200 |
| Edwardsville | Illinois state code | R-49 | Not published | 618-692-7535 |
| Glen Carbon | Illinois state code | R-49 | Not published | 618-288-2615 |
Free assessment, measured at the hatch, with the photographs and the number in writing.
The code edition Granite City enforces sets R-49 for new work. The Department of Energy separately recommends R60 for an uninsulated attic in this climate zone, and R49 where a few inches are already there.
Granite City has not published a rule for it. In practice that means one call to the building department before the job starts, which is on us rather than on you.
Ameren Illinois publishes $1.10 per square foot for attic insulation and $0.70 per cubic foot per minute (CFM) of air leakage reduced for air sealing on its 2026 discount table, applied by the contractor rather than paid to you directly. Two conditions decide whether it reaches you: air sealing has to be pre-approved before the work starts, and only a registered Ameren Illinois Program Ally can apply the discount at all. The federal 25C credit ended for work placed in service after 31 December 2025.
The typical home in Granite City dates to around the early-1960s. Postwar building here often meant three or four inches of fibreglass and no attempt at air sealing. If nobody has touched it since, that is what is still up there. That figure is an ACS-derived median republished by housing-data services, not a survey of individual houses.
Not yet. We have no completed job logged in Granite City, and we would rather say so than put a number on this page that is not real.
Illinois does not license insulation contractors as a trade, though it does run the residential energy code from Springfield rather than leaving it to each city. Municipal registration varies — some Metro East cities require a business licence, others require none at all. What matters more in practice is whether the contractor is a registered Ameren Illinois Program Ally, because only an Ally can apply the rebate.
Energy code, permit and department details for Granite City come from the jurisdiction's own published pages and codified ordinances. Rebate figures come from the utility's own published incentive tables and carry the programme year they were verified in. Housing-age figures are ACS-derived medians republished by housing-data services, so treat them as approximate. Sources: granitecity.illinois.gov · granitecity.illinois.gov · granitecity.illinois.gov · library.municode.com · en.wikipedia.org · en.wikipedia.org · ameren.com · ameren.com · ameren.com · ameren.com · energy.gov. Adopted code editions, department phone numbers and utility rebate amounts all change — confirm with the jurisdiction or the utility before relying on anything here.