A Charlotte multifamily developer called us last week with a blunt question: if they pushed their 48-unit project into permit review by the end of June, could they build the whole thing under the old code and avoid the cost bump everyone's talking about? Short answer: yes, if they move fast. Long answer: the savings are real—potentially $160,000 to $400,000 on a project that size—but the July deadline is a hard cutoff, and once the new code takes effect, every permit application filed after that date will trigger updated energy calculations, beefier wall assemblies, and a longer, more expensive review cycle.
The 2024 North Carolina State Building Code was supposed to go into effect in mid-2025. House Bill 47 delayed it, and the Building Code Council now expects adoption no earlier than July 2026. That delay just created a narrow window where developers and custom-home builders can lock in the current 2018 code, which is less stringent and significantly cheaper to comply with, simply by submitting permit applications before the switchover date.
Industry estimates peg the cost increase from the 2024 code at 2 to 5 percent of total residential construction costs. On a $400,000 custom home, that's $8,000 to $20,000 in added insulation, HVAC efficiency upgrades, and structural requirements. Scale that to a 20-unit infill multifamily building, and you're looking at $160,000 to $400,000 in delta between a June permit and an August permit—same building, same site, just a different rulebook.
What changed (and what didn't)
North Carolina adopts the International Code Council's I-Codes on a rolling cycle, typically lagging national publication by two to three years to allow time for state amendments and industry comment. The 2024 NC code incorporates updates from the 2021 International Residential Code and International Building Code, with state-specific tweaks around energy performance, structural wind loads, and accessibility.
The big-ticket changes driving cost are in energy efficiency. The 2024 code raises insulation R-values in walls and attics, tightens air-sealing requirements, and mandates higher-efficiency HVAC equipment in climate zones that cover most of the state. For a typical 2,400-square-foot house in Raleigh or Durham, that means:
- Wall insulation jumps from R-13 or R-15 to R-20 or continuous exterior insulation.
- Attic insulation moves from R-38 to R-49 in some applications.
- HVAC systems need higher SEER ratings, and duct-leakage testing becomes mandatory in more scenarios.
- Windows and doors face stricter U-factor limits, which often means upgrading to low-E glass or vinyl frames with thermal breaks.
None of those changes are optional, and none of them are cheap. The insulation delta alone can add $3,000 to $6,000 to a single-family frame package. HVAC upgrades run another $2,000 to $5,000 depending on system size and whether the existing design already spec'd high-efficiency equipment. Window and door swaps can push another $3,000 to $8,000 depending on quantity and frame material. Add it up, and the 2–5% range tracks with what we're seeing in bid comparisons between 2018-code projects and 2024-code prototypes.
Structural and fire-safety updates are less expensive but add review time. The 2024 code incorporates revised wind-load maps and updated seismic detailing, which means structural engineers need to rerun calcs even if the building footprint and height stay the same. Fire-rated assemblies in multifamily projects face tighter smoke-seal requirements, and egress paths have new geometry rules that can affect corridor widths and door swings. None of that doubles your budget, but it does lengthen the review cycle as plan examiners check new tables and cross-reference amended sections.
The grandfather rule: permits submitted before July lock in 2018 code
Here's the critical piece: under North Carolina law, a building permit application locks in the code edition that was in effect on the date of submission. If you submit a complete permit application in June 2026 and the 2024 code takes effect in July 2026, your project builds under the 2018 code—period. The AHJ can't require you to upgrade mid-review, and you don't have to resubmit drawings to meet the new energy tables or insulation schedules.
That rule applies to both residential and commercial projects, and it covers everything from single-family custom homes to large multifamily and mixed-use developments. The only caveat is that the application has to be complete—if you submit a partial set or a preliminary plan check and the AHJ kicks it back for corrections, the clock keeps running, and if the resubmittal lands after the code effective date, you may be forced to upgrade. Most North Carolina building departments define "complete" as a full set of sealed architectural and structural drawings, energy calcs, site plan, and any required third-party approvals (fire marshal, stormwater, health department), so this isn't a game you can play with a rough sketch and a cover letter.
We've already seen one Fayetteville GC submit a multifamily permit in early May specifically to beat the deadline, even though the foundation work wasn't scheduled to start until August. The permit sat in review for six weeks, came back with minor plumbing comments, and the resubmittal cleared in early July—after the code effective date—but because the original submission was complete and timestamped in May, the project is locked into 2018 code and the developer just saved an estimated $180,000 in insulation and HVAC upgrades on a 32-unit building.
Why July is the hard cutoff (and why you can't wait)
The Building Code Council hasn't published the exact effective date yet, but "no earlier than July 2026" means the window is closing fast. If the effective date lands on July 1, any permit submitted June 30 or earlier is safe. If the effective date lands on July 15, you have a couple extra weeks. But there's no way to know the final date until the Council votes, and by the time that vote happens, you'll have maybe a week or two to get permits into the queue.
That timing crunch is real. A complete multifamily permit package in Charlotte or Raleigh takes two to four weeks to assemble if you're starting from scratch—architectural drawings, MEP coordination, structural calcs, energy modeling, site civil. If you're waiting for the Council to announce the date and then scrambling to file, you'll miss the window. The safe play is to assume July 1 and work backward: if you want to lock in 2018 code, your permit needs to be ready to submit by mid-June at the latest, which means plan sets should be in final review by late May.
And "ready to submit" doesn't mean "mostly done." North Carolina AHJs have been tightening completeness standards over the past two years, and incomplete submissions get rejected outright rather than entered into review. If your structural drawings are missing a shear-wall schedule or your energy calcs don't include the mandatory REScheck report, the application gets handed back at the counter and you're re-filing a week later—possibly after the deadline.
We're advising clients to run a pre-submission completeness check with the local building department now, even if they're not filing until June. Most jurisdictions will do an informal desk review and tell you what's missing, and that feedback loop buys you time to fix errors before the clock runs out. In Durham, we had a custom-home client get flagged for a missing grading plan during a pre-check in April; they added the plan, resubmitted in May, and cleared review in early June—well ahead of the deadline. Without that pre-check, they would have missed the window and faced a $12,000 cost increase when the 2024 code hit.
The math on a 20-unit multifamily project
Let's walk the numbers on a hypothetical but realistic scenario: a 20-unit multifamily building in Greensboro, three stories, wood-frame over podium, $8 million total construction cost. Under the 2018 code, the building uses R-15 wall batts, R-38 attic insulation, and 14 SEER HVAC. Energy compliance is straightforward, and the wall assembly is a standard 2×6 frame with exterior sheathing and vinyl siding.
Under the 2024 code, the same building needs:
- R-20 walls, which means either thicker batts (2×8 framing, more lumber cost) or continuous exterior insulation (rigid foam, more labor).
- R-49 attic insulation, which is an extra 11 inches of blown fiberglass or cellulose.
- 15 or 16 SEER HVAC, depending on unit size, which bumps equipment cost by $1,500 to $2,500 per unit.
- Low-E windows with U-factor ≤0.30, which adds roughly $150 to $300 per window compared to standard double-pane.
Total delta per unit: $8,000 to $20,000. Across 20 units, that's $160,000 to $400,000. The developer who files in June pays the lower number; the developer who files in August pays the higher number. Same site, same unit mix, same finish level—just different insulation and glass.
And that's before you factor in longer review times. North Carolina building departments are already stretched thin, and the 2024 code introduces new tables, amended sections, and revised calculation methods that plan examiners will be learning in real time. The first wave of 2024-code permits is going to sit in review longer than 2018-code permits, because examiners will be cross-referencing updated standards and conferring with senior staff on interpretation questions. If your financing has a hard construction-start date or your site-work contractor is holding a summer schedule, that extra two to four weeks of review delay can cascade into real costs.
What if you're still in design?
If your project is still in schematic design or early design development, you probably can't hit the June deadline—and that's okay. Trying to rush a half-baked permit set into review just to lock in the old code is a good way to get rejected for incompleteness or accumulate so many review comments that you end up resubmitting after the deadline anyway.
The better move is to design and budget for the 2024 code from the start. Have your architect and engineer spec the higher R-values, the better windows, the tighter ductwork now, and price it into your pro forma so there are no surprises when you file in August or September. The cost increase is real, but it's also predictable—2 to 5 percent is a range you can model, and if you're working with a lender or equity partner, you can show them the code-change delta and adjust the budget accordingly.
What you don't want is to assume 2018 code pricing, start construction in October, and then discover mid-build that your insulation package is $40,000 short because the permit ended up under the new code. That's the scenario that kills contingency and turns a profitable project into a breakeven or worse.
Our read: file now if you can, plan for the new code if you can't
The July deadline is a genuine cost-saving opportunity for projects that are ready to permit. If your drawings are 80% complete and you have a clear path to a June submission, push hard to get there—the savings are worth the sprint. But don't sacrifice quality or completeness just to beat the clock; an incomplete submission that gets rejected and resubmitted after the deadline is worse than just designing for the 2024 code from the beginning.
For ADU and single-family clients, the same logic applies. A $400,000 custom home that files in June saves $8,000 to $20,000 compared to an August filing. If the plans are ready, that's an easy call. If the plans need another month of work, budget the extra cost and move forward on the right timeline.
We're tracking Building Code Council meeting schedules and will update clients as soon as the final effective date is published. If you're sitting on a North Carolina project and want to talk through permit timing, get in touch—we're running completeness checks and fast-tracking permit packages for multifamily and custom-home clients in Charlotte, Raleigh, Durham, and Greensboro, and we're happy to walk through whether a June filing makes sense for your specific scope.