In Birmingham's R2 single-family district, 394 of the 3,043 parcels studied fall below the district's 6,000-square-foot minimum lot area. That figure comes from the city's own zoning consultant. Across the four single-family districts, about 785 parcels sit on less land than their zoning calls for. Most owners only run into that fact when they plan an addition, a rebuild or a sale to someone who wants to do one.
On October 1, 2026, the consultant reached a clear conclusion in the Preliminary Recommendations Report. In many cases the mismatch belongs to the code, and the code should move closer to the houses that are already standing. The report says lot area standards "can become outdated and present barriers to investment," and it describes the analysis as a way to "reduce unnecessary barriers to reinvestment." For a buyer comparing older homes, or an executor pricing one, the size of the lot is fixed. What could change is how the rules treat that land, and those rules are under review now.
Where the friction shows up: the addition, not the closing
Under Birmingham's current ordinance, an older house that doesn't meet today's standards isn't in trouble just for existing. Section 126-6.02, Continuance of Nonconformity sets the terms:
- A nonconforming building that existed when the ordinance was enacted or amended "may be continued if maintained in good condition."
- It may be extended or enlarged if the extension or enlargement "does not itself violate any provision of the Zoning Ordinance."
- If the work would violate a provision, the owner applies to the Board of Zoning Appeals for a variance under Section 8.01(F).
- The building "shall not be rebuilt or repaired after damage exceeding 75% of the true market value of the building immediately prior to damage."
The variance step is where the friction lands for the next owner. Section 8.01(F) asks the Board of Zoning Appeals to make findings that include unnecessary hardship, consistency with the ordinance's purpose and the public welfare, and substantial justice. When a buyer's plan for a house depends on a family room addition or a second-story expansion, that standard decides whether the plan goes ahead.
The consultant's report treats variances as a recurring cost of reinvesting in Birmingham. One preliminary recommendation would let city staff approve minor changes to standards such as building height and setbacks "to provide greater flexibility, address common variance requests, and minimize barriers to reinvestment." Another would drop the required distance between buildings and rely on setbacks and lot coverage, which the report says "would reduce the need for variance requests while maintaining appropriate spacing between structures." These are still proposals, but they show where the city sees the most common friction.
The mismatch, district by district
Birmingham's four single-family districts currently require minimum lots of 20,000, 9,000, 6,000 and 4,500 square feet. The consultant counted how many parcels in each district fall short. Then it tested smaller minimums until the share of nonconforming parcels dropped to about 10 percent.
| District | Current minimum lot | Parcels analyzed | Below current minimum | Alternate tested | Below the alternate |
|---|---|---|---|---|---|
| R1A | 20,000 sq ft | 136 | 44, or 32% | 9,000 sq ft, one of several tested | 15, or 11% |
| R1 | 9,000 sq ft | 2,305 | 243, or 11% | 8,500 sq ft | 146, or 6% |
| R2 | 6,000 sq ft | 3,043 | 394, or 17% | 5,500 sq ft | 129, or 6% |
| R3 | 4,500 sq ft | 1,743 | 104, or 5% | None; current standard found appropriate | Not tested |
R1A stands out. Almost a third of its parcels are smaller than the district's half-acre standard. The consultant tested alternate minimums for R1A ranging from 18,000 square feet down to 8,000 square feet. R2 has the most nonconforming parcels by count, and a 500-square-foot reduction would cut that group by about two thirds. A small change on paper would reclassify a lot of land.
The report adds that the analysis includes about 20 institutional parcels, such as schools and places of worship, and that they don't significantly affect the findings.
The same math also counts which lots could become two
Lowering a minimum lot size has a second effect. The report defines a lot split opportunity as a lot at least twice the minimum lot area, so a smaller minimum makes more lots large enough to divide. The consultant ran that count too.
- R1A: 41 split opportunities under today's 20,000-square-foot standard, 97 if the minimum were 9,000 square feet.
- R1: 222 today, 292 at 8,500 square feet.
- R2: 129 today, 238 at 5,500 square feet.
- R3: 42 today; no alternate was tested.
So a single change in the table works in two directions. It brings undersized lots into conformance, and it lets more large lots, in theory, become two. Those counts are planning estimates, and they don't establish whether any particular lot can be divided. Under the current code, Section 126-4.27 restricts dividing combined contiguous residential lots under single ownership and sends lot divisions to Chapter 102 of the Birmingham City Code.
What the draft points toward, and what the city heard
Lot area is one part of a broader rewrite. For the single-family districts, the report recommends updating the R1A, R1, R2 and R3 bulk and dimensional standards "to reflect the different neighborhoods and their existing development patterns." It also says R1, R1A and R2 generally align with the master plan. Updates there would focus on infill standards so new development "is compatible in scale and design with surrounding neighborhoods."
The report summarizes what the city heard during outreach. Participants ranked similar building heights and spacing between buildings on neighboring lots above other compatibility standards, such as architectural details and garage placement. They also raised outdoor lighting standards and tree replacement when new construction removes trees. On housing types, the report says community feedback favored keeping single-family character in established neighborhoods, with some support for duplexes and cottage courts only in transition areas.
For accessory dwelling units, the draft would consider expanding detached ADU allowances. Those ADUs would have to be compatible with the main house, and the property owner would have to live in either the main house or the ADU.
Rebuilding is happening alongside all of this. Birmingham's 2025 permit register lists new-house permits from January through March pulled by Ideal Custom Builders, HRH Construction, Alimoff Building & Development, and Orchard Development & Construction. The 2026 register adds January permits for Godo Homes and Keystone Homes. A separate track could affect older homes as well. The March 2026 City Manager report says the Historic District Commission is studying a potential demolition delay ordinance as part of its Historic Preservation Master Plan, to be considered by the City Commission.
The rewrite moves slowly, and so does the county market right now
The Planning Board held its first review of the report on October 14. Downtown Publications reported that Houseal Lavigne senior project manager Carrie Papelbon presented the analysis of how smaller minimums could reduce the number of nonconforming properties. The board took no formal action. In the same Downtown Publications account, board chair Scott Clein said, "This board, in front of the public with public comment, will vet every single one of these points if they're left in the report, and will vet every single change that is proposed in this ordinance at the appropriate time over the course of the next many, many months."
The city's Zoning Ordinance Update page listed a joint Planning Board and City Commission meeting for October 26 and a regular study session on December 9. The city expects the project to be completed in August 2027. The recommendations are still a draft, so the current district standards and Section 6.02 are the rules on the books.
The wider market gives buyers a bit more room to ask these questions before they write an offer. Realcomp's September 2026 report shows Oakland County inventory at 4,084 in September 2026, up from 3,256 in September 2025. Closed sales slipped from 1,410 to 1,349, and the median sale price rose from $375,000 to $383,500. Those figures combine residential and condo sales countywide; they aren't Birmingham-specific. More inventory and fewer sales leave more time for zoning questions before an offer is due.
Why this matters for an estate or a long-held home
Executors, trustees and longtime owners often hold the houses this analysis is about. These are older homes on lots that were platted before today's minimums, sometimes next to a second parcel the family also owns. The questions that shape a buyer's interest are concrete. Is the house nonconforming? Would the addition a buyer has in mind need a variance? Does Section 4.27 apply to adjoining lots under one owner? Answers depend on the parcel, and the city's Planning Department offers appointments on Mondays and Wednesdays to discuss the zoning update.
Having those answers before a home goes on the market belongs in preparing a seller's listing, and it carries extra weight in a trust or probate sale, where the fiduciary needs a clear record behind the asking price. For a broader look at the city, see our Birmingham neighborhood page.
A few questions that come up
Is a Birmingham house on an undersized lot something to avoid?
The ordinance doesn't treat it that way. Section 6.02 lets a nonconforming building continue if it is maintained in good condition. The limits apply to enlargements that would break the code and to rebuilding after damage over 75 percent of the building's value.
Has Birmingham lowered its minimum lot sizes?
No. As of the October 14 review, the reduced minimums were tested alternatives in a preliminary report, and the Planning Board took no formal action.
Does the rewrite address ADUs in single-family neighborhoods?
The draft recommends considering expanded detached ADU allowances, with compatibility standards and a requirement that the owner live on the property.
This post is general information, not legal advice. Anyone weighing an addition, a lot division or a sale should confirm how the ordinance applies to their parcel with the city and a qualified attorney.
If you're responsible for an older Birmingham home and want to know where its lot stands before you set a price or a timeline, Abby Kushner can help you collect the parcel details, coordinate with your attorney or trustee, and plan the sale step by step. Schedule a Confidential Consultation.
