As prophesied (we had a blog post about it), the Great Changing has come to pass (on schedule): on July 1, the Philadelphia 2021 building codes took effect!

As we explained previously, the switch technically happened back on January 1, and we were in a grace period from then until July 1. In effect, that just meant things continued as normal under the existing building codes for the first half of 2026. Now, finally, the new rules have been passed into law and will be enforced for all construction projects in Philadelphia.

The new building codes are the 2021 editions of the regulations created by the International Code Council (not actually an international organization), as amended by Pennsylvania. Collectively, the 2021 ICC and the PA amendments are the “Uniform Construction Code” (UCC) for the Commonwealth. Philadelphia, as it always does, added even more local amendments to the UCC to govern work in the city. The results are generally referred to as the “2021 codes.”

The direction for new projects is simple: design buildings, additions, and renovations in accordance with the 2021 codes.

For existing projects, things might be trickier: what happens if you got approval for one permit under the old codes but haven’t applied for the others? What happens if you have to amend permits approved before July 1? What if you already have your building and excavation permits but haven’t pulled trade permits?

Let’s go through these cases, starting with amendments and trades.

Quick Reference: Philadelphia 2021 Building Codes by Permit Type

Permit Amendments and Trade Permits

If you apply for a permit amendment, you can still use the old 2018 codes, so long as two criteria are met:

• The original permit was designed under the old (2018) codes
• The original permit must have been issued; you can’t amend a permit if you haven’t already paid for it and received the actual PDF permit document, even if the permit status is listed as “ready for issue”

This amendment rule does not apply to trade permits, meaning HVAC, electrical, plumbing, or fire suppression permits (there’s some murkiness around fire suppression, but to keep things simple, we’ll treat it like the other trade scopes). If you want trade permits reviewed under the 2018 codes, you’d better have already applied for them before the July 1 cutoff. If you didn’t, you need to submit the trade permits under the 2021 codes. And that leads to the next important code transition rule:

No Mixing Code Editions

L&I won’t allow permit applicants to mix codes. If you have a building permit in hand but haven’t applied for your trade permits, you’ll need to apply for those (HVAC, electrical, plumbing, or sprinkler) under the new 2021 codes. You could, in theory, start construction under the building permit, but you wouldn’t be able to do any trade work under the 2018 codes. If the 2021 standards for the trades conflict with any part of the original design, you’ll have to amend the building permit to accommodate the trade permit requirements. You can’t just incorporate some 2018 code rules into, say, the electrical design to avoid amending the original building permit.

Similarly, all permits for Planned Unit Developments (PUDs) or similar multi-phase projects designed under the 2018 codes must have been filed before July 2026: even if the overall development plan, the “Master Plan,” as L&I calls it, feeling dramatic, was approved before July 2026, it will be considered invalid unless all the related permits were also filed before July 2026. Same deal for preliminary approvals: any preliminary authorization granted under the 2018 codes is now invalid unless you already applied for the related permits before July 1.

An example: if you’re working on a PUD of 10 houses designed to satisfy the 2018 building codes, you would have needed to submit applications for the master permit for overall development and building permits for all 10 houses before July 1. If you didn’t get all of those permit applications into review before the start of July, you now need to redesign the entire PUD according to Philly’s new building codes: all the remaining applications must be submitted under the 2021 codes.

Now, in that hypothetical PUD, let’s say you did get all the building permits under the 2018 codes. You still need to apply for trade permits, again: HVAC, plumbing, electric, sprinkler, under the 2021 codes.

We’ve had clients ask us, “Would the City of Philadelphia really force projects partially permitted under the old codes to get 2021 code authorization?” And that’s how we know those clients haven’t worked in Philly for very long.

(In case that joke didn’t land: yes, the City would 100% for sure hold up a project for that reason.)

What’s Actually in the New Building Codes

Now that you know all that, you might wonder: how do the new codes differ from the ones we’ve used for the last few years?

This question is way beyond the scope of a single post, but here’s a very limited overview of some big changes:

• An entirely new building type is introduced: mass timber! This allows for really tall, like, 15+ stories tall, buildings framed by composite wood products instead of steel or concrete
• PA has created a new certification system for shipping containers used in modular, residential construction
• Change of occupancy rules, which can mandate, among other types of work, new sprinklers, can now be triggered by any change “in the purpose of” or “in the level of activity within” an existing building
• Sprinklers are required more often in general. Perhaps most notably, they’re now required for lower levels of alteration to existing buildings and for parking garages over a certain size
• Puzzle rooms, yep, escape rooms and the like, are now defined and regulated by the building code
• Energy conservation compliance rules for building envelopes are a lot different than they were, to the point that the standard way of demonstrating compliance in the past, a ResCheck or ComCheck, is probably not the best or most cost-effective method to use anymore
• Related to the note above: air leakage testing is now required for all apartment or condo units in a commercial building

Frequently Asked Questions about the Philadelphia 2021 Building Codes

When did Philadelphia’s 2021 building codes take effect? The 2021 codes technically took effect January 1, 2026, with a grace period through July 1, 2026, during which projects could still be reviewed under the 2018 codes. As of July 1, 2026, all new applications must comply with the 2021 codes.

Can I still amend a permit under the 2018 building codes? Yes, if the original permit was designed under the 2018 codes and was actually issued (not just approved or listed “ready for issue”), amendments to it can still use the 2018 codes.

Do trade permits get the same 2018-code exception as amendments? No. Trade permits (HVAC, electrical, plumbing, sprinkler) only qualify for 2018 codes if they were already applied for before July 1, 2026. Miss that deadline, and they must be submitted under the 2021 codes, even if the related building permit was approved under 2018 codes.

What happens if I have a building permit but haven’t applied for trade permits yet? You can start construction under the 2018-code building permit, but any trade work must be permitted under the 2021 codes. If the 2021 trade standards conflict with your original building design, you’ll need to amend the building permit. Philadelphia’s L&I doesn’t allow mixing code editions within a single project.

Does a Planned Unit Development (PUD) get more time to file under the 2018 codes? No. All permits tied to a PUD’s Master Plan, including individual building permits, had to be filed before July 1, 2026, for the Master Plan to remain valid under the 2018 codes. Anything filed after that date must comply with the 2021 codes, regardless of when the Master Plan was originally approved.

We’ll post some more on this blog about specific changes in the months ahead.

In the meantime, you can always drop us a line with any questions. We’d love to hear from you!