If your building has an extra bedroom that was never permitted, a basement apartment that was finished without inspection, or a garage that became a studio, here is the short version: for lending purposes, that space does not exist. It is excluded from the appraised value and excluded from the revenue the underwriter uses to size your loan. The rent you collect on it is real. It just does not count.
That single exclusion is where most surprises in a small-balance commercial file come from. An owner who has collected on eight units for six years applies against eight units of income, and the file comes back sized against six. Value falls, the loan-to-value ratio you assumed is wrong, and the coverage ratio that looked comfortable no longer clears. Nothing about the building changed. What changed is that a certified appraiser and a credit underwriter looked at it through a legal lens rather than an operational one.
This page explains what that lens does, why it cascades, and what your options are.
The rule, stated plainly
The Fiirm program guidelines address unpermitted space directly, and the language is short.
Read that twice, because it contains two separate consequences and borrowers usually only hear the first one.
The first consequence is arithmetic. The unpermitted units come out of the income statement and out of the value conclusion. That reduces both the numerator of your coverage ratio and the denominator of your loan-to-value ratio, which is a bad combination.
The second consequence is a gate. Removed or permitted. Those are the two paths the guideline names. It does not describe a path where the illegal portion stays in place, uncounted, while the loan closes around it. If the unpermitted portion remains as-is, the transaction does not move forward on that basis.
Who decides, and when you find out
An appraisal report is required on all property types, and every report is reviewed by a state certified general appraiser on the lender side before underwriting relies on it. The review analyst checks the report for quality and for compliance with USPAP and FIRREA, and where the analyst reaches a different conclusion on value, the analyst's opinion sets the internal value used for the file, though never higher than the appraised value.
Practically, this means unpermitted space usually surfaces at the appraisal, not at application. The appraiser measures the building, pulls the municipal records, and reconciles the two. A basement apartment with a kitchen and a separate entrance that appears nowhere in the permit history is exactly the kind of discrepancy that gets written up.
That timing is the problem. By the time it appears you have paid for a report, you are weeks into the process, and your proceeds assumption is already baked into whatever you planned to do with the money.
Legal, legal non-conforming, and illegal are three different things
Borrowers collapse these into two categories, conforming and not, and that is where the confusion starts. The guidelines treat them as three, and only one of them is fatal.
| Status | What it means | Program treatment |
|---|---|---|
| Legal conforming | The use and the improvements comply with the current zoning ordinance | Acceptable |
| Legal non-conforming | The use predates the current ordinance and was lawful when built, so it is permitted to continue even though it would not be allowed today | Acceptable |
| Illegal or unpermitted | The space or use was created without the required permits or approvals, or violates the ordinance with no protected status | Not acceptable; excluded from value and revenue |
Legal non-conforming is the category that saves buildings. A six-unit apartment building on a lot that today would allow only four units is not an illegal building if it was built lawfully under the ordinance in force at the time and has continued in that use. It is grandfathered. The appraiser states the classification and the compliance status, and the file proceeds with all six units counted.
Unpermitted is different in kind, not in degree. A converted garage has no protected status because it was never lawful in the first place. There is no prior ordinance under which it was permitted. It is undocumented square footage generating undocumented income.
Two adjacent rules catch owners who assume rezoning is the fix. Properties zoned residential or agricultural are not eligible for this program at all, and the program will not lend on a property subject to a zoning change. A pending rezoning is not a solution to an eligibility problem; it is a second one. Separately, a commercial use sitting inside a residential zoning district under a special use permit is eligible only to a maximum loan-to-value of 50%.
The cascade, illustrated
This is the part that is hard to see from inside the building. The following is an illustration built on invented figures to show the mechanics. It is not a quote, not a guideline number, and your appraiser's conclusions will differ.
Take an eight-unit apartment building. Six units are permitted. Two were created later, a finished basement apartment and a converted garage, both rented, both never permitted.
The owner's operating statement and the underwritten operating statement now diverge.
| Line | Owner's view (8 units) | As underwritten (6 units) |
|---|---|---|
| Gross rent, 8 units at $1,500 | $144,000 | $108,000 |
| Less vacancy and credit loss at 5% | $136,800 | $102,600 |
| Less operating expenses | $47,880 | $47,880 |
| Net operating income | $88,920 | $54,720 |
| Indicated value at a 7% capitalization rate | $1,270,000 | $782,000 |
Look at the expense line, because that is the part nobody expects. The guideline language removes the unpermitted units from revenue and from value. It does not describe a matching reduction in operating expenses, and as a practical matter most of those expenses do not shrink anyway. The real estate taxes are assessed on the whole parcel. The insurance covers the whole structure. The roof, the boiler, the water bill, and the management fee do not fall by a quarter because two units stopped counting.
So the exclusion is not proportional. Removing 25% of the units removed 38% of the net operating income in this illustration, and value fell by roughly the same proportion. If an appraiser did scale a portion of the variable expenses down, the gap narrows but does not close; on these same figures a proportional expense allocation would still land value near $953,000, more than $300,000 below the owner's number.
Now run that reduced value through the two constraints that size a small-balance commercial loan.
Loan-to-value. The ratio is calculated on the lower of the internal value from appraisal review, the adjusted sales price net of material credits, or the appraised value. An investor cash-out or refinance is capped at 75%. Against the owner's $1,270,000 assumption, a $900,000 request looks like a comfortable 71%. Against the $782,000 underwritten value, the same request is roughly 115%, and the ceiling is about $586,000.
Debt service coverage. For investment properties, the underwritten DSCR is underwritten net operating income divided by annual debt service. Investor Complete and Investor Lite require 1.15x. Owner-occupied files are measured on a global basis at 1.20x, which pulls in personal and business obligations as well. In this illustration, a $586,000 loan against $54,720 of net operating income produces coverage of about 1.01x, which does not clear. Sizing back to 1.15x lands the loan near $515,000.
Coverage binds before value does, which is typical. The same building with all eight units permitted would support roughly $838,000 on the same assumptions. The two unpermitted units, in this illustration, cost more than $320,000 of proceeds, and none of that is a penalty. It is just the arithmetic of underwriting a smaller building than the one the owner thinks he owns.
When the unit count itself breaks eligibility
The cascade above assumed the building stayed eligible. Sometimes it does not, and this is the failure mode owners never see coming.
Multi-family under this program means five or more residential units, and the eligible property type definition adds a specific condition: all units must have full and legal kitchens. The mixed-use definition carries the same requirement for the residential component.
Follow that through on a six-unit building where two units are unpermitted. Counted units drop to four. Four residential units is not multi-family under this program; one-to-four unit properties fall under separate guidelines entirely. The building did not shrink and no tenant moved out, but the asset has moved out of the program on a definitional basis rather than a credit one.
Mixed-use owners have a parallel exposure. The tier classification depends on which component generates more than 50% of gross rental income, calculated by dividing the monthly rent of the residential or commercial units by the total monthly rent of the property. Strip unpermitted residential income out of that calculation and the ratio can flip, moving the property from Tier I to Tier II with everything that follows from the tier.
Where unpermitted work stops being an exclusion and becomes a decline
Not every permit problem is a quiet subtraction. Several conditions make a property unacceptable collateral outright rather than merely worth less.
The distinction between an unpermitted unit and a material illegal use is a judgment made on the facts of your property, informed by the appraisal and the review. A finished basement with a kitchenette is one conversation. A structure whose primary improvement is itself unlawful is another. The guidelines do not publish a line between them, and this page will not invent one.
Condition matters here too. Where an appraiser reports the property in Fair condition, an additional real estate review is triggered to determine whether the property is acceptable. Repair items should carry the appraiser's estimated cost to cure, and deferred maintenance that is a life or safety issue may itself be a reason to decline, with evidence of repair required before closing. Unpermitted work and deferred maintenance often travel together.
One more flag: a property containing multiple designs and uses may be treated as a special purpose property, and special purpose properties are ineligible. An owner who has informally carved a building into mismatched uses can create that problem without intending to.
What an owner can actually do
There are two honest paths, and one thing that is not a path.
Legalise the space. Permitting existing work after the fact is a municipal process. It generally involves your building department, drawings, inspections of work already concealed behind finished walls, and compliance with the code in force now rather than when the work was done. Whether it is possible at your property, what it costs, and how long it takes are questions for your municipality and your attorney. The guidelines are silent on all three and this page will not guess. What they do say is that once the portion is permitted, the obstacle in the rule box above is resolved.
Remove the unpermitted portion. The guideline names removal as the alternative to permitting. That means physically restoring the space to a lawful configuration and losing the income. It is the right answer more often than owners expect, particularly where legalisation is impossible because of parking, egress, ceiling height, or density limits.
What is not a path: financing the cure with loan proceeds. Reserves and holdbacks exist in this program for reasonable repairs that improve the property and for principal and interest reserves, with a holdback period that may not exceed 180 days. But repairs and renovations involving structural work, new construction, or retrofit of the subject property are ineligible for that treatment. Bringing an unpermitted basement apartment to code is usually structural or retrofit work. Plan on curing the condition with your own funds before closing, not out of the loan.
Planning around it, before you apply
If you know or suspect you have unpermitted space, the work is front-loaded.
- Pull your permit history from the municipality and reconcile it against your rent roll, unit by unit. The gap between those two documents is your exposure, and you can measure it yourself in an afternoon.
- Rebuild your operating statement on the permitted units only, holding operating expenses at the full-building level. That is the statement that will be underwritten.
- Re-run your loan request against that statement at the applicable coverage requirement, 1.15x for investor files under Investor Complete and Investor Lite, 1.20x global for owner-occupied. Compare the answer to what you need.
- Check the unit count against the five-unit multi-family floor, and check that each counted unit has a full and legal kitchen.
- Take the permitting question itself to your building department and a local land use attorney before you take it to a lender. Whether your basement apartment can be legalised is not a credit question.
Do this and one of two things happens. Either the deal works on legal units, in which case the unpermitted space becomes irrelevant to the financing, or it does not, in which case you learned it at the cost of a phone call rather than an appraisal fee and a month.
What this page does not do
This page explains how unpermitted and illegal units are treated in valuation and underwriting under The Fiirm's SBC program guidelines. It does not do the following.
It does not tell you whether your specific space can be permitted. Permitting, code enforcement, variance procedure, and grandfathered status are municipal and legal matters that vary by jurisdiction and by property. Those questions belong to your building department and your attorney, not to a lender.
It does not estimate the cost or timeline of legalising anything. The guidelines are silent on both, and any figure here would be invented.
It does not price a loan or quote proceeds. The dollar figures in the illustration are invented to demonstrate mechanics; the capitalization rate, rents, expense ratio, interest rate, and amortization are assumptions, not offers. Real value comes from an appraisal ordered through an approved appraisal management company, and real proceeds come from an underwritten file.
It does not classify your property. Whether an unpermitted portion is a discrete exclusion, a material illegal use, or a major code violation is determined on the facts of the file after appraisal review.
It does not address one-to-four unit residential properties, which fall under separate guidelines, and it does not address programs other than SBC.
If you want to know what your building supports on its permitted units, that is a conversation worth having before you order anything.
Guideline SBC 08/03/2026 · Reviewed August 31, 2026
Published August 31, 2026 · Updated August 31, 2026
How to use this guide
This article is educational guidance, not an offer or commitment to lend. Rules, property facts, credit, leverage, documentation, and full underwriting still control any actual scenario.