The unpermitted work nobody thought to file for
Long Island housing stock has been extended, finished and converted for generations, and permits were not always the habit. A good share of the square footage people live in today was added quietly over a few weekends.
That is why this comes up so often at the closing table. The house you have been living in and the house on file at the town are two different houses, and the gap between them is what unpermitted work actually means.
How we help Mastic owners with unpermitted work
Buying the house is the part everyone understands. It is rarely the whole of what somebody in this position needs.
We have been buying houses on Long Island for 15+ years and we have legalized plenty of unpermitted work in that time, so we know the expeditors, the architects who draw the as-built sets, and the attorneys worth calling when a file is genuinely stuck. We make those introductions whether or not the Mastic house ends up being ours. Describe what was built and roughly when, and we will tell you what permits are likely involved.
What this looks like in Mastic specifically
Mastic is roughly 15,404 people in Suffolk County, ZIP 11950, and the housing stock is mostly ranch, cape cod, bungalow. Around Montauk Highway and Mastic Road, most of it is old enough that the mechanicals are on their second or third life. We have bought enough here to know which streets take water, which blocks still have oil tanks in the ground, and what the William Floyd Union Free School District does to a resale price.
Prices are up 16.5% year over year as of 2026-05, which sounds like unambiguous good news and mostly is. What it hides is that a rising median is driven by renovated stock. A house that needs work does not ride that wave - it gets compared to the finished one down the street and marked down against it. At a $540,000 median, Mastic is a market where buyers expect to do some work. That helps a seller with a dated house and hurts one with a genuinely broken one, because the pool that will take on a project is not the same pool that will take on a gut. The median house here goes under contract in about 27 days, which is quick for Long Island. It is also a figure that only applies to property in showable condition.
Why the buyer's lender cares about unpermitted work
Two separate parties care, which is what makes this harder than people expect. The lender wants the value it is lending against to be real and legal. The title company wants the buyer to take the property without open items attached to it.
An open permit or a missing sign-off can show up as an exception on a title report, and work done off the books has a way of producing both at once. Satisfying one of them is manageable. Satisfying both on a contract timeline is where sellers come unstuck.
Legalizing unpermitted work after the fact
Getting work approved after the fact is possible sometimes and impossible other times, and which one you are in turns on details nobody can judge from the outside. Setbacks, lot coverage, ceiling heights, egress, how current code differs from the code in force when it was built.
Your town's building department decides what can be permitted now, and an expeditor will know how that department tends to handle it. What we can tell you is that the process runs slower than a sale does, which is the practical problem.
What the two paths cost in Mastic
These are the two routes open to you with a house with unpermitted work, priced against what Mastic houses actually sell for.
Work it against Mastic's own numbers. The median sale here is $540,000. A 5% commission on that is $27,000, and seller closing costs of about 2% add roughly $10,800. Those are costs we can cover on our side. That is $37,800 gone before anyone counts the repairs it took to get the house listable.
There are two waits in a listed sale and people usually only count the first. In Mastic the median house takes about 27 days to go from listed to a signed contract. Then it waits again, typically 45 to 60 days, while the buyer's lender orders an appraisal and underwrites the loan. Call it 72 to 87 days from sign to keys, assuming nothing goes wrong.
The part worth understanding is what a signed contract actually guarantees, which is less than most sellers assume. A retail buyer with a mortgage contingency can walk away right up to the end. If they do not qualify, if the appraisal comes in under the price, if they change their mind and let the financing lapse. A share of deals die exactly there, after months of waiting, and the house goes back on the market with time on it. We are not borrowing anything, so there is no lender to satisfy, no appraisal to come in low and no contingency to exercise.
| Listing with an agent | Selling to us | |
|---|---|---|
| Sale price | $540,000 (Mastic median) | Our written offer |
| Commission | −$27,000 | None |
| Seller closing costs | −$10,800 | We can cover them |
| Repairs before listing | Out of pocket | None |
| Cleanout | Yours | Ours |
| Showings | Until it sells | One visit |
| Listed to signed contract | 27 days (Mastic median, once listable) | 24 hours to a written offer |
| Contract to closing | 45 to 60 days (waiting on the buyer's lender) | A date you choose |
| Total wait | 72 to 87 days if nothing falls through | Yours to set |
| Can the buyer walk? | Yes (mortgage contingency runs to the end) | No financing to fall through |
| Before repairs and carrying | $502,200 | The number we put in writing |
The agent column uses a 5% commission and about 2% of seller closing costs, which are typical rather than fixed. It leaves out repairs and holding costs because no two houses are alike there. Where a house is in good condition, listing with a capable agent can beat our number, and we will be upfront if that is the case.
Which route nets more when the work was never permitted
Sometimes legalizing first is genuinely the better move, and we will tell you when we think so. A deck that needs a permit and an inspection is a different proposition than a garage conversion the zoning may never allow.
The calculation turns on what has to be spent before anything is recovered. Permit costs, drawings, the corrective work an inspector asks for, and the months the house carries while all of it happens. A cash sale frequently wins on the net rather than on the headline number.
How we arrive at a number on a house with unpermitted work
On a house with unpermitted work we start from the end: what it sells for once the work is done. From that we take away the cost of the work and a margin for the chance that we have misjudged either one. That is the whole method. Nothing is hidden in it.
- What it is worth repaired. Not the Mastic median of $540,000 on its own, but what houses like yours on your street actually closed at recently.
- What the work costs. Roof, boiler, electric, the kitchen and bath. In Mastic the stock is largely ranch and cape cod, and on houses that age the mechanicals are usually the expensive part rather than the cosmetics.
- How long we will hold it. The median Mastic house goes under contract in about 27 days once it is showable, then waits 45 to 60 days more on the buyer's lender. Ours has to get to showable first, and we carry taxes and insurance across the whole of it.
- What we are wrong about. Walls and floors hide things until they come up. We price for that uncertainty, and it accounts for much of the distance between a cash offer and a retail price.
How we can pay this and still make it work
Most cash buyers skip this part. We do not. We run millions of dollars of construction a year, so we buy materials at contractor prices and keep our crews busy all year. The same renovation costs us roughly half of what you would be quoted as a homeowner.
That difference is how we make money. It is also why renovating before you sell seldom comes out ahead: you would pay retail for the roof and the boiler and then hope a buyer pays you back for them. Most of the time they do not. Our margin comes from building for less, not from buying from you for less.
If our number does not work for you, tell us. We would much rather hear it than push. We will go through your situation and give you a straight view of your options, including the ones that leave us out. A lot of people do better listing with an agent, and if you are one of them we will tell you now rather than have you find out later.
No permit has to be pulled before you sell
The next step is short. Tell us what was built and roughly when, send whatever the town has sent you, we come out once, and you get a written number within a day.
No permits, no drawings, no cleanout, and no sign on the lawn in Mastic. If what we see suggests the work could be legalized easily enough that you would net more that way, we will tell you so and give you the name of the expeditor we would use.
Common questions
Will unpermitted work stop a buyer getting a mortgage on a Mastic house?
Frequently, yes, and it is the reason unpermitted work matters far more at sale than it ever did while you lived there. The loan is secured against the house as the town's records describe it, and an unpermitted addition is not in those records. Some Mastic buyers get past it with a cooperative lender and a long timeline. Many do not. Selling for cash removes the question entirely.
Do I have to pull permits before selling my Mastic house?
Not to sell to us. We buy with the work unpermitted and take the file on afterward. Whether you need them for any other purpose is worth putting to an attorney.
The previous owner did the unpermitted work. Does that change anything?
It is extremely common and it does not affect our offer. What you are personally exposed to is an attorney question, but unpermitted work done by a previous owner is not a reason we walk away.
Will the town find the unpermitted work when I sell my Mastic house?
A buyer's attorney will usually order a municipal search, which is where open permits and missing sign-offs surface. Selling to us does not require that search to come back clean.
There is already a violation for the unpermitted work. Can you still buy?
Yes, and it is a common starting point for these conversations. Tell us what the notice says and we will price it once rather than being vague now and revising on you later.
How much does unpermitted work take off the price of a Mastic house?
It depends what it would take to legalize it and what the risk is that the town says no. A finished basement is usually a smaller adjustment than an addition sitting in a setback. We would rather price it accurately once than revise later.