How to Get a Permit for Work Already Done (Retroactive / As-Built Permits)
Built or bought something without a permit? Here's the honest, step-by-step path to an after-the-fact permit, from as-built drawings to final inspection.
I've spent a long time as a firefighter here in Kansas City, and I started PermitDeck because I kept running into homeowners who got blindsided by permit problems they never saw coming. If you found this page, I'm guessing you already built the deck, finished the basement, added the bathroom, or bought a house with work that was never permitted, and now you're trying to make it right. Before anything else, take a breath. This is a fixable problem, and choosing to deal with it instead of hoping nobody notices is exactly the right call.
The permit you're looking for goes by a few names: an after-the-fact permit, a retroactive permit, or an as-built permit. Different building departments use different words, but they all mean the same thing, which is a permit for work that's already finished. I'm going to walk you through how it actually works, what tends to surprise people, and how to get through it without losing your mind. I'll be straight with you about the parts that aren't fun, because you deserve to know what you're walking into.
Quick Answer: To permit work that's already done, document the existing work, prepare as-built drawings showing what was actually built, and apply for an after-the-fact permit with your local building department. The work gets reviewed against today's code, you'll likely pay an added investigation fee, and an inspector may need to open up walls or ceilings to verify concealed work before you get final sign-off.
What an "after-the-fact" permit really is
An after-the-fact permit is the same building permit you would have pulled before the work started, just applied for after the fact. The building department isn't trying to punish you for existing. Their job is to confirm the work is safe and meets code, and a permit is simply how they document that they checked.
The big difference from a normal permit is timing, and timing changes a few things. Because the work is already built and often closed up behind drywall, the department has to figure out what's back there and whether it was done right. That's where as-built drawings, investigation fees, and destructive testing come in. I'll cover each of those below.
If you want the full picture on the risks of leaving unpermitted work alone, I wrote a companion guide on what happens if you build without a permit that pairs well with this one.
The step-by-step process
Here's the path almost every retroactive permit follows. Your local department may add a wrinkle, but the bones are the same everywhere.
Let me unpack the ones that surprise people.
Why it's judged by today's code, not the old code
When you permit work after the fact, the building department reviews it against the code that's in effect right now, not the code that was in effect when the work was originally done.
This trips up a lot of folks, especially with older houses. Something that was perfectly acceptable when it was installed decades ago may not meet the current standard. Electrical requirements in particular have changed a lot over the years, driven by real safety lessons. So an older installation might need to be updated to satisfy today's rules before it can pass. It isn't the inspector being difficult. The code is the code, and the version that matters is the current one.
The practical takeaway: budget for the possibility that you'll need to bring some things up to current standards, not just document what's already there.
The investigation fee, and why it varies
Almost every jurisdiction charges an extra fee when you permit work after the fact, often called an investigation fee or a penalty fee, on top of the normal permit cost.
I'm going to be honest with you here, because there's a lot of bad information online. You'll see confident claims that it's "2 to 3 times the permit fee" or a flat "$500 to $2,000." Don't trust those numbers. They're generalizations copied from blog to blog, and they don't reflect what your specific city or county actually charges. The real answer is that it varies, sometimes a little and sometimes a lot, depending on where you live.
The right move is to look up your local building department's fee schedule, or just call them and ask. Most departments will tell you plainly what the after-the-fact fee is. If you're not sure which office handles your address, my guide on how to look up building permits shows you how to find them and check what's already on record for your property.
Destructive testing: why they open up the walls
Here's the part of my job that makes this section personal. As a firefighter, the calls that scare me most are the ones where something failed inside a wall where nobody could see it. A wiring connection that was never done right. Framing that wasn't strong enough. A plumbing leak quietly rotting the structure. Concealed work is exactly what inspectors worry about, because once the drywall goes up, nobody can tell whether it was done safely just by looking at the finished surface.
That's why an inspector may require destructive testing, which means opening up walls, ceilings, or other finished surfaces to expose the wiring, framing, or plumbing so it can actually be verified. I know that's frustrating to hear when you just finished the space. But there's no way to confirm that concealed work is safe without seeing it, and "we'll take your word for it" isn't how safety works.
This is the point where I usually tell people to bring in help. If your project involves concealed electrical, structural, or plumbing work, it's worth hiring a licensed contractor to find a licensed pro to open up the work and get it inspected rather than guessing at it yourself. A good one knows what the inspector will be looking for and can make the corrections in the same visit. If your situation is an unpermitted deck instead, the same logic applies with a qualified deck builder.
What getting legal actually protects
I want to leave you with why this is worth the hassle, because it's more than a bureaucratic box to check.
The goal here was never to punish you. It's to make the work safe and legal, and to give you the paperwork that proves it.
Frequently Asked Questions
Is it better to just leave unpermitted work alone?
Usually not. Unpermitted work tends to surface at the worst possible time, like during a sale, a refinance, or an insurance claim. Dealing with it on your own schedule is far less stressful than being forced to handle it during a closing. It also means the work finally gets checked by someone qualified for safety.What does "as-built" mean?
As-built drawings show what was actually constructed, as opposed to a proposed design drawn before the work starts. Since your project already exists, the building department needs an accurate picture of the real thing, including dimensions and any electrical, plumbing, or structural details, so they can review what's genuinely there.Will I really have to tear open my finished walls?
Sometimes, yes. If the work is concealed behind drywall, an inspector may require destructive testing to expose wiring, framing, or plumbing and verify it's safe. It doesn't always happen, and the amount varies by project, but you should be prepared for the possibility, especially with electrical or structural work.How much is the penalty for an after-the-fact permit?
It varies by jurisdiction, and I won't quote you a figure I can't stand behind. Most departments add an investigation or penalty fee on top of the normal permit cost, but the amount differs from one city or county to the next. Check your local building department's fee schedule, or call and ask them directly.Can I do the as-built drawings and application myself?
For a simple project, sometimes yes. For anything structural or involving concealed systems, a licensed professional usually needs to prepare the drawings and may be required to make corrections. When in doubt, call your building department and ask what they'll accept before you invest time in drawings.Does a retroactive permit mean my work will definitely pass?
Not automatically. The permit is the process, not a guarantee. Your work is reviewed against current code and inspected, and you may need to make corrections before final sign-off. The upside is that once you pass, the work is genuinely legal and documented, which is what protects your resale, your insurance, and your peace of mind.Doing this the right way protects your home, your family, and the next people who live there. It's not the fun part of owning a place, but it's the responsible one, and you're already doing it. Take it one step at a time.
Stay safe out there. Brian