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A Raleigh buyer considering an owner-occupied duplex with a permitted backyard cottage may be able to finance the property under Fannie Mae's expanded rules. But the buyer can't assume the cottage's rent will help them qualify for the mortgage.
That distinction matters after two developments in November 2026.
On November 2, a new appraisal reporting format called Uniform Appraisal Dataset 3.6, or UAD 3.6, became mandatory for new appraisal reports submitted through the portal shared by Fannie Mae and Freddie Mac, subject to approved lender exceptions.
Fannie Mae had already expanded financing eligibility for certain properties with accessory dwelling units, or ADUs, beginning March 31 for qualifying loans using UAD 3.6. Then, on November 4, it extended that eligibility to certain condo properties.
For Raleigh buyers, the changes create more possibilities for financing homes with backyard cottages, converted garages and other independent living spaces.
But three decisions still matter: whether the city recognizes the additional dwelling, whether the lender can finance the property and whether any rent can count toward the buyer's income.
Here are five findings that can affect a purchase.
1. November's Appraisal Mandate Follows March's Expanded ADU Eligibility
The November 2 deadline concerns appraisal reports, not when a buyer applies for a mortgage.
Under the new UAD 3.6 standard, appraisers use a redesigned report to document property characteristics, including accessory dwelling units and relevant rental information.
Fannie Mae's appraisal portal guidance identifies the initial submission date as the trigger. The appraisal's effective date and the mortgage application date don't determine whether the new submission requirement applies.
Approved lender exceptions remain possible. Freddie Mac's implementation guidance also addresses the transition because both mortgage enterprises use the shared portal.
Fannie Mae made its broader ADU property eligibility available March 31, 2026 for qualifying loans using UAD 3.6.
Its current UAD 3.6 Selling Guide supplement allows a qualifying non-manufactured, one-unit principal residence outside a condo project to have as many as three ADUs.
An owner-occupied two-unit property may have up to two ADUs. An owner-occupied three-unit property may have one.
The combined limit is four residential units.
Consider a hypothetical Raleigh property with a duplex and one detached cottage.
The buyer intends to live in one side of the duplex and rent the other. The cottage provides a third independent dwelling on the same lot.
Fannie Mae's expanded policy can accommodate that arrangement as a two-unit principal residence with one ADU, provided the property meets the remaining eligibility requirements.
That doesn't mean every property with four living spaces qualifies. A four-unit primary dwelling cannot use this ADU pathway, and the expanded policy excludes second homes, investment properties and other specified property classes. Factory-built and manufactured housing have separate qualifications.
Fannie Mae's allowance also doesn't give a Raleigh owner permission to build additional cottages.
2. A Raleigh Permit and a Fannie Mae-Eligible ADU Aren't the Same Thing
A listing might describe a backyard cottage, garage apartment, guest house or in-law suite.
Those descriptions don't establish whether the space was legally approved as a separate dwelling or whether a lender will recognize it as an ADU.
Raleigh's ADU building guidance distinguishes detached units from spaces converted inside existing structures.
A garage converted to residential use follows the city's separate ADU change-of-use process.
A home may have a nicely finished garage with a kitchenette and bathroom, but its appearance doesn't establish its approved use. A buyer needs the permit history and evidence that the required inspections and approvals were completed.
Fannie Mae applies its own definition.
An ADU must be on the same parcel as the primary dwelling and have independent living, sleeping, cooking and bathroom facilities, along with separate ingress or egress.
A space accessible only through the main dwelling, or open to it without privacy, doesn't meet that definition. A second kitchen alone isn't enough.
Two Raleigh houses advertised with garage apartments could therefore receive different treatment.
One may have a completed, permitted conversion with the necessary independent facilities and access. The other may have unfinished approvals or a layout that the lender cannot classify as an ADU.
The appraisal must reflect the actual property, not simply repeat the listing description.
HomesRaleigh's guide to how listings and appraisals measure square footage explains another related distinction: additional living space isn't necessarily included in the main home's finished square footage.
Raleigh has its own limits on how many ADUs a parcel can contain
Raleigh's permit guidance describes one detached ADU on a qualifying duplex parcel, bringing the property to three residential units.
The city also provides a separate pathway for two ADUs on qualifying parcels in designated Frequent Transit Areas, with additional zoning and building-code conditions.
Fannie Mae's national financing limits don't replace those local requirements.
Buyers should check the applicable Raleigh zoning requirements for the specific lot.
They also need to establish whether the home is actually within Raleigh city limits. A Raleigh mailing address alone doesn't settle which local government's development rules apply.
A lender may be able to finance a property that fits Fannie Mae's expanded ADU limits, but the city must still recognize the existing dwelling or proposed use under its own rules.
3. The Cottage's Rent May Not Count Toward Mortgage Qualification
Return to the hypothetical Raleigh duplex.
The buyer plans to occupy one side, rent the other and eventually collect rent from the backyard cottage.
That's potentially two rental payments helping support the property. For mortgage qualification, however, the lender has to evaluate the income sources separately.
Fannie Mae's UAD 3.6 Selling Guide supplement has a specific ADU rental-income provision for one existing ADU with a one-unit primary residence.
For qualifying purchase or limited cash-out refinance transactions, a lender may be able to count income from that ADU, subject to documentation and underwriting requirements.
The amount of ADU income used cannot exceed 30% of total qualifying income.
Suppose a buyer instead wants a single-family primary residence with one existing backyard cottage.
Qualifying rent from that cottage might help the buyer obtain the mortgage if the property and income meet Fannie Mae's requirements.
But the lender must establish an acceptable rental amount. The applicable rental-information section of the UAD 3.6 appraisal report is part of that documentation, along with a fully executed lease if one is transferring with the property. Fannie Mae also requires documentation involving the borrower's current housing payment.
A rent estimate in the listing isn't automatically the income the lender will accept.
The duplex and cottage involve different income rules
Fannie Mae's expanded property rules may allow the two-unit residence with a detached ADU. But the specific ADU-income provision for a one-unit primary residence doesn't automatically extend to that cottage.
Rent from the duplex's other primary unit may qualify under Fannie Mae's separate rental-income rules for two- to four-unit principal residences.
The lender must determine how each unit is classified, which income provisions apply and how much income underwriting will accept.
Consider the difference for a buyer whose budget depends on collecting rent from both units.
If underwriting can use rent from the second duplex unit but not the cottage, the amount the buyer can qualify to borrow may be lower than expected.
Fannie Mae's separate short-term rental-income pathway doesn't allow ADU income, either. Projected short-term cottage rentals don't provide another route under that provision.
If rental income is necessary for the purchase to work, ask the lender which program applies, how it will classify the dwelling units and what rental income it can document and accept before setting a purchase-price ceiling.
4. Fannie Mae's November 4 Update Adds Certain Condo Properties
Two days after the appraisal-submission mandate began, Fannie Mae made another change.
Its November 4 Selling Guide Announcement SEL-2026-10 extended UAD 3.6 ADU property eligibility to certain condominium units.
Lenders could apply the update immediately.
The change allows one qualifying ADU with a one-unit principal residence in an eligible condominium project.
But a condo advertised with separate guest quarters doesn't automatically qualify.
The condominium's governing documents must expressly permit the ADU. It must be on the same parcel as the primary condo unit and cannot be separately owned, sold, transferred or financed.
The same mortgage must secure both.
The condo project itself must also meet Fannie Mae's applicable eligibility requirements.
If the additional space is legally a separate condominium unit, the arrangement isn't necessarily the same as one primary condo unit containing an eligible ADU.
The lender has to review both the unit arrangement and the project's governing documents.
The November 4 update expands which condo properties may qualify for financing. It doesn't establish that rental income from those ADUs will count toward the buyer's mortgage qualification.
5. Check the Property Records Before Counting on the Cottage
The first step for a buyer considering a Raleigh home with an existing ADU is to establish what the property legally contains.
Ask the seller for the approved plans, permits and records showing completed inspections or occupancy approvals.
Raleigh's Development Records page directs buyers to the Permit and Development Portal, where permit, inspection and occupancy information may be available.
Not every project's documents will be downloadable. Availability varies by date and project type, making the seller's records especially useful.
Compare the paperwork with what the listing advertises. A cottage described as a separate apartment should have a documented use that supports that description.
Then ask the lender to resolve three questions before relying on the extra space in the purchase budget:
- How will the property be classified? Is it a one-unit primary residence with an ADU, a two-unit property with an ADU or another arrangement?
- Does that arrangement qualify for the intended mortgage? The answer depends on the lender's program, the property and the applicable Fannie Mae requirements, not just Raleigh's permit approval.
- How much rental income can actually be used? The lender should identify which unit's rent qualifies, the required evidence and the amount underwriting will accept.
The appraisal also has to support the property's value. If it comes in below the agreed purchase price, HomesRaleigh's guide to low appraisals in North Carolina explains the options buyers may need to consider.
Before making an offer that depends on cottage income, have the lender review the proposed property arrangement and explain which rent it can use to qualify you. The answer could change how much you can afford to offer.
Browse Raleigh homes for sale and use listing descriptions to spot cottages or converted garages worth a closer look.
Conceptual illustration of a backyard cottage beside a brick home.
