How to Request Approval for an Alternative Method

Why this matters

The prescriptive code describes one way to do most things, and it says plainly that it does not forbid the others. Every adopted I-code carries a provision letting the building official approve a material, design or method the code does not prescribe, if it meets the code's intent and is at least equivalent to what is prescribed. Shops that know how to use it get approval for the faster fastener, the product that solves an awkward existing condition, the method that saves a day. Shops that do not either never ask, or install first and ask later, which turns a reasonable request into a demand that the official accept work already hidden behind finishes.

This card walks the request through one real-shaped job, step by step. What an evaluation report proves, and how to read one line by line, are covered elsewhere. See related: Evaluation Reports and What They Prove, and How to Read an Evaluation Report Before You Use a Product.

The provision, briefly

In the 2021 IRC, as adopted, this is R104.11, alternative materials, design and methods of construction and equipment. The 2024 edition reorganized the administrative chapter and moved it, so in that edition look for the same title rather than the number. Its substance, paraphrased:

• The code does not prevent a material or method it does not specifically prescribe, provided the building official approves it.
• The official approves where the alternative complies with the intent of the code and is at least the equivalent of what is prescribed in quality, strength, effectiveness, fire resistance, durability and safety.
• Where the official does not approve, the reasons must be stated in writing (the IRC's wording; check your adopted text).
• The official may require tests, by an approved agency and to recognized standards, at no cost to the jurisdiction.

Those six attributes are the checklist your request answers. A request that argues only one of them, usually that the alternative is "just as strong", leaves the official five reasons to say no.

The job used throughout

A deck shop is adding a 12 by 14 ft deck to a 1980s house, attached with a ledger to the house's band joist. The prescriptive ledger provisions in the 2021 IRC (R507.9, as adopted) call for half-inch lag screws or bolts at spacings from a table. The crew wants to use a structural screw marketed as an alternative to those lags: no pilot holes, faster to drive, and backed by a third-party evaluation report.

The steps

1. State the prescriptive requirement and the intent it serves

Write down exactly what the code prescribes for this condition, by section, and in one sentence why it is there. For the ledger: the fasteners carry the deck's vertical load and resist the deck pulling away from the house, and ledger failure is a leading cause of deck collapse.

Why this step comes first: equivalence is measured against the prescribed method, so you cannot argue equivalence without naming it. Skip it and the request reads as "we would rather not", which is how a request gets denied.

On the job: the shop's one-line statement reads, "R507.9 prescribes half-inch lag screws or bolts at the tabulated spacing to transfer vertical and lateral loads from ledger to band joist; we propose a structural screw that the attached evaluation report qualifies for the same connection."

2. Ask how this department handles alternatives

Departments differ. Some accept any product with a current evaluation report covering the use, at plan review, with no separate request. Some want a written request for anything non-prescriptive. Some route structural alternatives to an engineer's design every time. A two-minute call tells you which. See related: How to Ask the Building Department a Code Question.

Skip it and you either write a formal request nobody needed, or skip a request somebody did.

On the job: this department wants a written request for any ledger fastener other than lags or bolts, submitted with the permit application, with the evaluation report attached.

3. Assemble the evidence, strongest first

Evidence for an alternative comes in tiers. In rough order of how much weight an official gives them:

1. A current evaluation report from an accredited evaluation service, covering this use, under the code edition the permit is issued against.
2. Test reports from an approved testing agency to a recognized test standard.
3. A design sealed by a licensed engineer for this specific installation.
4. Manufacturer literature alone, which states what the maker claims and has no independent check behind it.

Why the order matters: an official approving on manufacturer literature alone is taking responsibility for a claim nobody independent has checked. Bring the strongest tier available. Where only the fourth tier exists, expect the official to ask for the third.

On the job: the screw has a current evaluation report. The shop checks three things on its cover page before relying on it: it lists the 2021 IRC among the codes it was evaluated against, its renewal date is after the planned install, and its scope names deck ledger attachment.

4. Match the job to every condition of use, and say how you will prove each one

An evaluation report approves a product under stated conditions, not in general. List each condition and, beside it, how this job meets it and how anyone can check that in the field.

Skip it and the approval covers a product, not your installation, and the first unmet condition the inspector finds voids it.

On the job, the report's conditions (illustrative) and the shop's answers:

The first row is the one that could have stopped the job. If the band joist's grade stamp is not visible, the shop either opens a small area of ceiling to find it or falls back to the prescriptive lags; it does not guess the species. And the ledger flashing the IRC requires is unaffected by the fastener choice: the alternative replaces the fasteners, not the rest of the ledger provisions.

5. Submit before the work, in writing

Put the request on one page: the prescriptive section, the proposed alternative, the six-attribute equivalence argument in a sentence each, the conditions table, and the attached evidence. Submit it with the permit application or as soon as the alternative is chosen.

Why before: an official deciding before installation can say yes, no, or yes with conditions. An official deciding after can only accept work they cannot see or order it removed, and many will not approve under that pressure on principle.

On the job: the request goes in with the permit application, so plan review handles both together.

6. Get the decision in writing and attach it to the permit

An approval should be written, name the product and the report, and state any added conditions. If it arrives verbally, write it down yourself with the name and date and send it back to the official to confirm. If the request is denied, the code requires written reasons; read them as a list of what a second request has to answer. See related: How to Document a Code Interpretation You Were Given.

Skip it and the inspector who arrives at the ledger inspection has no idea the plans examiner agreed to anything.

On the job: approval comes back with one added condition, a photo of the grade stamp in the permit file before the ledger is installed.

7. Build to the conditions and leave the evidence for the inspector

Keep the evaluation report, the approval and the product packaging on site. Install exactly to the report's spacing and edge distances, and do not substitute a different screw length or coating on the day because the supply house was out. See related: How to Keep Installation Instructions for the Inspector.

Skip it and you have an approval for a product that is not the one in the wall.

On the job: at the ledger inspection the inspector compares the screw heads' marking to the report's identification section, measures the spacing against the plan and signs off.

If the official says no

A denial with written reasons is not the end. The common reasons are that the evidence does not cover the edition, the report's conditions do not match the job, or the official is not satisfied on one of the six attributes. Answer the stated reason with better evidence, often an engineer's letter, or build the prescriptive way. Where you believe a denial misreads the code itself, the adopted code's board of appeals is the formal route (R112 in the 2021 IRC); it is slow and worth it only for decisions that will repeat across many jobs. This is not legal advice; an appeal that turns on contract or liability questions goes to your own attorney.

How to verify you got this right

• The request names the prescriptive section and answers all six equivalence attributes, not only strength.
• The evidence covers the code edition on the permit and is current on the install date.
• Every condition of use is matched to the job with a field-checkable proof, and any condition you could not prove sent you back to the prescriptive method.
• The approval is written, names the product and report, and lives in the permit file and on site.
• What got installed matches the approval exactly, down to length and coating.

References

• International Residential Code, 2021 edition, R104.11, R112 and R507.9, as adopted by your jurisdiction
• The evaluation service's published report and its conditions of use for the specific product
• See related: Evaluation Reports and What They Prove; Field Evaluation When a Product Has No Listing; The Inspector Relationship: Pass the First Time