What R-Value Insulation Do I Need in Kansas City? Climate Zone 4A Requirements by Adopted Code Edition

What R value insulation do I need in Kansas City? The honest answer is that no single number exists. The required R-value depends on the energy code edition your city or county adopted and on the kind of building, so read your edition first and the number second. The values below are printed only next to their edition and climate zone. Anything outside that frame, including the newest edition, would be a number that does not apply to most offices around Spring Hill.

This page is a reference table, not a ruling on your building. Which office issues your permit is on permits and adopted codes by office. PolyJacks sprays closed-cell foam only, inside buildings within about 35 miles of Spring Hill, KS.

Illustrative

Which edition applies to you

An edition is the year of the model International Energy Conservation Code (IECC) that a place enforces. Each city or county picks an edition and may amend it, so two neighbors can follow codes years apart. The permit-by-office table lists the adopted edition per office, each row read from a primary page on 2026-10-25 or marked unknown. Here is what that table implies for insulation, without adding any office that was not read.

Kansas City, Missouri and the other Missouri and Kansas offices not listed have no row because no page for them was opened. You should verify Kansas City, MO's adopted IECC edition directly from its own page, as search results vary.

Climate zone: Kansas City is 4A

The climate zone sets which row of every table below applies. A 2009 compliance guide for Kansas lists these counties under zone 4: Anderson, Douglas, Franklin, Johnson, Leavenworth, Linn, Miami and Wyandotte, along with most of the state (Insulation Institute, IECC Compliance Guide for Homes in Kansas, 2009 IECC). The matching Missouri guide lists Bates, Cass, Clay, Jackson and Platte under zone 4 (Insulation Institute, IECC Compliance Guide for Homes in Missouri). A Department of Energy laboratory report on Kansas City, MO describes Jackson County as zone 4A (PNNL-20263, 2011).

Those lists come from the 2009 edition's map. A summary of the 2021 changes from one state's code office says various towns changed climate zone in the 2021 edition, none in that state (Delaware DNREC, 2021 IECC changes). So confirm your county on the map that goes with your office's edition, ideally from an ICC or DOE source.

Moisture control is a separate question from R-value and is on why a metal building sweats.

What R value insulation do I need in Kansas City: residential zone 4 values

For homes and for residential-type buildings under the code, the U.S. Department of Energy's Building America Solution Center compares the prescriptive R-value tables for the 2009 to 2021 editions (BASC, 2009-2021 IECC and IRC Minimum Insulation Requirements). For climate zone 4 except Marine, which is the Kansas City row:

Two things the table says in passing. First, the 2012 to 2018 values are the same, so a county on the 2018 edition and one on 2012 share these numbers. Second, the 2021 values are a step up. A code-office summary describes the 2018 to 2021 change for this zone as ceiling R-49 to R-60 and wood-frame wall R-20 or R-13 + R-5 to R-30 or the continuous-insulation options (Delaware DNREC). That state's zone 4 is the same model-code row as ours; the table values are the model code and apply to any office that adopted the edition without amending it.

Where R-30 shows up

R-30 appears often in searches for "R30 ceiling insulation." In the zone 4 row above it is not the attic requirement for any edition shown. R-30 does appear in the code in a narrower place: a county compliance form for the 2018 IECC lists R-30 for roof rafter insulation, not to exceed 500 sq ft, as an alternative to the full ceiling value (Greeley, CO, 2018 IECC compliance form). That form is for zone 5 and a different jurisdiction, so read it only as a pointer to the section that holds the rule. Check the 2018 IECC text for the specific section number and area limit applicable to zone 4 rafter cavities. The 2018 and 2021 summaries also describe a reduction for attics where uncompressed insulation extends fully over the exterior wall top plate, from R-49 to R-38 in the 2018 edition and from R-60 to R-49 in 2021 (Delaware DNREC).

When your office amended the table: Lawrence

Lawrence adopts the 2018 IECC through Ordinance 9632 and reprints Table R402.1.2 with its own markup (City of Lawrence, Ordinance 9632-9632.pdf)). In the version we read, the zone 4 except Marine row shows ceiling R-49 and a wood-frame wall entry edited by hand: the model code's 20 is struck and 19 is underlined, so the wall reads 19, or 13 + 2. The model code's value for this row is R-20 or R-13 + R-5 (table above). Lawrence's row also lists a fenestration U-factor of 0.35 and an SHGC of 0.40, against 0.32 in the model table. The point is not Lawrence's wall number. The point is that an ordinance can change a number, and the office's own table, not the model code, governs. Ask your office for its table in writing.

Steel framing and residential-type buildings

The 2009 Kansas and Missouri guides above cover wood-frame and mass walls only. For steel-framed buildings they send the reader to the code's own metal-frame section (402.2.5 in the 2009 edition) for ceiling, wall and floor values, and the same guides say they do not reflect state amendments. For a shop with living space, a barndominium or a steel-framed home, ask the building official whether the residential or commercial chapter applies. That ruling changes the table you use.

Metal buildings and other commercial values

A steel shop used for business, a warehouse or a machine shed is normally read under the commercial energy chapter, not the residential table. The commercial rows differ in kind: they cover roofs, above-grade walls, floors and slabs, are given as R-values or as U-factors for a whole assembly, and have separate rows for metal buildings.

The one Kansas City figure set we opened is a Department of Energy laboratory comparison for Kansas City, MO, climate zone 4, between the 2006 and 2009 commercial editions (PNNL-20263, Table 1). It lists assembly U-factors, and a smaller U means more resistance:

The last column is our arithmetic and rounds; it is whole-assembly resistance, which is why it differs from the rated R on a product. The report also says the 2009 edition revised metal building insulation to be more stringent and to require continuous insulation sheathing on metal building walls, and that its zone 4 requirements represent Jackson County, MO. These are the 2009 values. The 2012, 2015, 2018 and 2021 commercial values for metal buildings were not opened here.

For a sense of what a later table can look like, one state's published energy-code chapter lists, in the R-value form, "R-19 + R-11LS" for a metal building roof and "R-13 + R-13ci" for a metal building wall (Rhode Island 510-RICR-00-00-8.6, Table C402.1.3). The page we read does not say which IECC edition that table follows or which zone those entries are for, so those two entries are an example of the notation, not a Kansas City requirement. The notation means a blanket plus a liner system, which is the arrangement described on metal building insulation options compared.

Unconditioned buildings: when the envelope rules may not apply

A U.S. Department of Energy training deck on the 2018 IECC commercial envelope, hosted by the University of Illinois, summarizes section C402.1.1: buildings or portions of buildings separated from the rest by a code-compliant envelope are exempt from the envelope provisions when they are low-energy buildings, or when they contain no conditioned space (Illinois Smart Energy Design Assistance Center, 2018 IECC Commercial Envelope). The low-energy test in that summary is a peak design energy rate for space conditioning under 3.4 Btu per hour per square foot. Equipment buildings have a separate set of conditions.

Read that in three careful steps.

1. It is a summary of one edition's commercial chapter. Your office may have adopted another edition or amended it.
2. "No conditioned space" depends on how the building is used and heated. A shop with a unit heater is a different case from cold storage. A PNNL report on the 2009 edition adds that the IECC has no separate envelope requirements for semiheated spaces, so nonresidential requirements are used for them (PNNL-20263). Whether a given building counts as heated is for the building official to say.
3. An energy-code exemption is not a fire-code exemption. What must cover foam in a building is a separate chapter, on thermal barrier and ignition barrier, and the Kansas farm-building zoning exemption does not decide energy-code questions either; see the Kansas ag exemption.

If the building has no permit trigger and no code R-value applies, the R-value you choose is your own decision. How thick to spray for the condensation check is on how thick closed-cell foam should be, and how R per inch is stated and aged is on closed-cell spray foam R-value.

Turning a code R into inches, and where this goes next

Divide the code R by the R per inch on the specific product's data sheet and round up to a sprayable thickness; the data sheet, not a generic figure, is the source, and the office's reviewer should say how foam counts for your assembly.

FAQ

What R-value insulation do I need in Kansas City?

It depends on the energy code your office adopted and on the building type, so read your row's edition first. For a new home in zone 4 the model-code attic value is R-38 in the 2009 edition, R-49 in 2012 to 2018 and R-60 in 2021, but your office's table governs.

What climate zone is Kansas City?

Climate zone 4A for the area, per the DOE laboratory report and county lists above, and the eight Kansas and five Missouri counties we read are listed under zone 4 in the 2009 guides. Confirm your county on the map for your office's edition.

Is R-30 enough for a ceiling in Kansas City?

Not under the zone 4 tables above for any edition shown, which start at R-38. R-30 appears in the code only in narrower cases such as limited rafter areas; ask the building official before relying on it.

Does a metal building need the same R-value as a house?

Not the same table. A commercial or metal building is read under the commercial chapter, which has its own rows, and a building with no conditioned space may be outside the envelope provisions. Which chapter applies is the building official's call.

Book a free on-site measurement

The code question and the building question meet at the measurement. On the visit we record wall and roof areas, the structure, how the space is used and heated, and anything the office will ask about, so the foam thickness you price is tied to a real number. You get a written estimate after the visit. The visit is free; how it works is on the free estimate visit.

Book a free on-site measurement

Pick "Spray foam insulation" on the booking form. We work within about 35 miles of Spring Hill, KS.

Spray foam insulation is a new PolyJacks service line run by its own crew and rig.

Who wrote this: PolyJacks spray foam team. Table checked: 2026-10-25; rows expire 2027-10-25. How it was made: drafted with AI assistance from the sources below, then checked against each source.

Sources

• Building America Solution Center (U.S. DOE), 2009-2021 IECC and IRC Minimum Insulation Requirements for New Homes: basc.pnnl.gov
• Delaware DNREC, Delaware Energy Code Update, Residential (2021 IECC), Performance Systems Development summary of 2018 to 2021 changes: documents.dnrec.delaware.gov
• Insulation Institute, IECC Compliance Guide for Homes in Kansas (2009 IECC): insulationinstitute.org
• Insulation Institute, IECC Compliance Guide for Homes in Missouri (2009 IECC): insulationinstitute.org
• Pacific Northwest National Laboratory, PNNL-20263, Comparison of 2006 IECC and 2009 IECC Commercial Energy Code Requirements for Kansas City, MO (March 2011): pnnl.gov
• City of Lawrence, KS, Ordinance 9632 (2018 IECC, amended Table R402.1.2): assets.lawrenceks.gov
• Greeley, CO, 2018 IECC Residential Energy Code Compliance Form (hosted by Weld County): weld.gov
• Rhode Island 510-RICR-00-00-8.6, Chapter 4 [CE], Table C402.1.3, via Cornell LII: law.cornell.edu
• University of Illinois Smart Energy Design Assistance Center, 2018 IECC Commercial Envelope and IBC (DOE Building Energy Codes Program training slides): smartenergy.illinois.edu
• Johnson, Douglas, Spring Hill, Olathe and Cass County edition entries are carried from the permit-by-office page (insulation-permits-codes-by-city-and-county), where each was read from the office's own page on 2026-10-25.