How to Find Local Code Amendments

Why this matters

The code you can read for free online is the model code, and the model code is almost never exactly the code at the address you are working on. States amend it when they adopt it, cities and counties amend it again, and the model code leaves some values blank on purpose for the jurisdiction to fill in. A footing dug to the depth printed in a neighboring city's ordinance, a shed built without a permit because the model code's exemption was larger than the local one, a sprinkler requirement quoted that the state deleted years ago: each is the same mistake, reading the model book as if it were the law.

These steps find the code that actually applies to one address. How adoption cycles work in general, and how to stay current on changes, belong to other cards. See related: Building Code Cycles + State Adoption, and Staying Current on Code Changes Without a Full-Time Job of It.

The steps

1. Pin the jurisdiction from the parcel, not the mailing address

Look the address up on the county's property or GIS map and read which jurisdiction the parcel sits in: a city, a township, a village, or unincorporated county. Mailing addresses follow post office routes, not city limits, so a house with a city name on its envelope is often in the county.

What breaks if you skip it: every later step researches the wrong ordinance, and nothing in the research tells you so. The values look plausible because they came from a real code, just not this one.

2. Find the state layer and how much room it leaves

States differ widely in how they adopt building codes, and the difference decides where amendments can live:

• Some adopt a statewide code that applies everywhere and restrict local changes. New Jersey's Uniform Construction Code is an example.
• Some adopt a model code as a baseline and let cities amend it. Texas adopted the IRC as the residential code for its cities and allows local amendments, while unincorporated areas of Texas counties often have no residential building code at all.
• Some publish their own integrated version rather than adopting the model book by reference. California's residential code is part of its state building standards, printed as its own document with state changes built in.

The trade codes may follow a different path from the building code. A state electrical board may adopt the NEC on its own schedule, and a state may use the Uniform Plumbing Code rather than the International Plumbing Code. Look up each code your work touches, not just the building code.

What breaks if you skip it: you find a city amendment and miss that the state already changed the same section, or you look for a city ordinance in a state where cities cannot amend.

3. Get the adopting document itself

Find the actual text that adopts the code: the state's administrative code or building code council rules, and the city or county's codified ordinances, usually in a chapter titled something like buildings and building regulations. Read three things from it before reading any amendment:

• Which edition of each code is adopted.
• The effective date, and any grace period during which permits may still be issued under the prior edition.
• Which appendices, if any, are adopted. An appendix is not law unless named.

What breaks if you skip it: you research amendments to the 2021 edition when the permit will be issued under the 2018 one. See related: The Edition on the Permit, Not the Newest Edition.

4. Read the amendment list against the sections you will work in

Amendments are written as instructions: a section deleted, a section amended to read differently, a new section added. Read them for the sections your job touches, and read them for the values the model code leaves to the jurisdiction. In the IRC, the climatic and geographic design criteria table in R301.2 (numbered R301.2(1) in some editions) is printed blank in the model code: ground snow load, wind speed, frost line depth, termite and decay exposure, winter design temperature, ice barrier requirement and flood hazard data are filled in by the adopting jurisdiction. The permit-exemption list is also a frequent local amendment.

Here is the shape of what you are looking for. This is a mock; the values are illustrative:

COUNTY BUILDING CODE ORDINANCE (illustrative)

Sec. 6-2  Adoption. The 2021 IRC, as amended by
          the state, is adopted, effective Jan 1,
          with the changes in Sec. 6-3.
Sec. 6-3  Amendments.
  (a) Table R301.2 is completed as follows:
        Ground snow load ......... 30 psf
        Frost line depth ......... 36 in
        Ice barrier required ..... yes
  (b) R105.2, item 1, is amended to exempt one
      detached accessory structure not over
      120 sq ft. (Model text reads 200 sq ft.)
  (c) Section R313 is deleted.

Line (c) mirrors a real pattern: many states removed the IRC's requirement for automatic sprinklers in new one- and two-family dwellings when they adopted it.

What breaks if you skip it: you build to the model code's permit exemption or its sprinkler requirement, and both are wrong for this address in opposite directions.

5. Do not trust the model code page you found online

The free read-only model codes published online show the model text, sometimes of a different edition than your jurisdiction adopted, and without the amendments. They are excellent for reading the structure of a section and useless for confirming what is required at an address. If your state publishes an integrated version, that is the document to read; if not, read the model text and the amendment list side by side.

What breaks if you skip it: the most common version of the mistake this card exists to prevent.

6. Call the building department with the section number

Once you have read the documents, call the building department and ask about the specific sections, by number, for the specific address. Ask two questions the ordinance cannot answer: whether there are written local policies or interpretations on that section, and whether an adoption of a newer edition is pending. Departments routinely have written policies that never reach the ordinance. See related: How to Ask the Building Department a Code Question.

What breaks if you skip it: you are correct about the ordinance and still wrong about how the department applies it.

7. Write it down where the next job will find it

Record the jurisdiction, the editions, the adopting document and its effective date, the amended sections relevant to your trade, the filled-in design values, and the name of the person you talked to with the date. Put a re-check date on it tied to the next adoption cycle. See related: How to Document a Code Interpretation You Were Given.

What breaks if you skip it: the research is repeated on every job in that jurisdiction, or worse, not repeated after the next adoption.

Worked example: a deck on the wrong side of the city line

A handyman shop is quoting a 12 by 16 ft attached deck with six footings. The customer's address carries the city's name. The shop has built decks in that city for years and knows its ordinance sets frost line depth at 42 in (illustrative).

Step 1. The county GIS map shows the parcel in unincorporated county, about a quarter mile outside the city limits. The city ordinance does not apply.

Step 2. The state adopts the IRC statewide as a minimum and lets counties adopt it with amendments. The county has.

Step 3. The county ordinance adopts the 2021 IRC as amended by the state, effective January 1 of last year. No appendices relevant to decks.

Step 4. The county's completed design criteria table, read in the ordinance, sets frost line depth at 36 in (illustrative) and requires an ice barrier, which matters for the roof job the customer also mentioned. The county's permit exemption for accessory structures is 120 sq ft, so the shed the customer wants later needs a permit at 144 sq ft (12 by 12), where under the model text's 200 sq ft exemption it would not.

Step 5. The online model code shows the frost depth cell blank, as expected. It would have given no number at all, which is safer than giving the wrong one.

Step 6. The county building department confirms the 36 in figure, says it has a written policy accepting a prescriptive deck guide it publishes, and notes no adoption of a newer edition is scheduled this year.

What it changed. The shop's habit would have dug six footings to 42 in, 6 in deeper than the county requires. That is the safe direction, and it costs dig time on every footing. Reverse the situation, with the shop used to the county's 36 in and building inside the city at 42 in, and the footings come up 6 in short, fail the footing inspection, and get re-dug before concrete. The research took about 30 minutes; one failed footing inspection costs a return trip and a schedule slip.

How to verify you got this right

• You can name the jurisdiction for the parcel and say how you established it.
• For each code your work touches, you know the adopted edition, its effective date and whether the state or the locality amended it.
• The design values and permit exemptions in your quote came from the adopting document or the building department, not from the model text or habit.
• Your record shows who confirmed it, when, and when to re-check.

References

• International Residential Code, 2021 edition, R105.2 (work exempt from permit), R301.2 (climatic and geographic design criteria) and R313, as adopted and amended by your state and locality
• Your state's building code adoption statute or regulation, and your city or county's codified ordinances
• See related: Building Codes Hierarchy Reference; Reading Which Code Book Governs This Job; How to Ask the Building Department a Code Question