Do You Need a Permit to Replace a Roof in Maryland? It Depends on the County

Maryland never wrote a statewide answer to “do I need a permit to replace my roof.” The state adopts the Maryland Building Performance Standards, based on the IRC and IBC, but the statute that puts them into effect hands the job to the local level: “except as otherwise provided in this subsection, the county in which a building or structure is located shall implement and enforce the Standards for that building or structure,” and “each local jurisdiction shall determine the manner in which the minimum implementation and enforcement activities… are carried out.” The subsection’s own exceptions let a municipal corporation enforce the Standards in its own borders instead of the county, so the office in charge is the county, or in some places the municipality. Either way, Maryland has no statewide permit exemption list: the state adopts the model codes, but the local jurisdiction implements and enforces them and may add its own amendments, which prevail. There is no state roofing exemption to look up, because the legislature never wrote one. The county, or the municipality where one runs its own department, did.

That leaves the real answer sitting in four different local rulebooks, and the 4 Maryland jurisdictions we have verified a Roof Replacement Permit row for do not agree with each other. 3 of them make the permit conditional on what the job touches. 1, Montgomery County, most likely needs no permit for a straightforward re-roof under the county’s own home-improvement list, though even that list carves out historic properties. None of the four treats an ordinary re-roof as permit-required no matter what, and each one carves out its own exception for a special property class, named below.

Baltimore County: the 50 percent sheathing test

Baltimore County’s roofing and siding permit page states the rule plainly: a permit is required “to undertake residential or commercial roof repairs if 50 percent or more of the sheathing or deck is being replaced,” citing Part 112.1.3 of the county’s Building Code, Bill 49-24. A permit is also required for replacement of any structural component, and for all roof repairs, regardless of scope, on a property in a proposed or designated Baltimore County Historic District or on the county’s Landmarks List. The same page grants one exemption worth knowing before you assume the worst: a permit is not required to put two layers of shingles on a roof.

Its own apply button reads “Apply for a Residential Alteration Permit.” Our row reads that routing against the county’s Building Permit Fee Schedule (effective 07/01/26), which carries no roofing line item at all: if construction plans are required, alterations run $105.00 under 600 sf without structural changes, and $160.00 either with structural changes under 600 sf or at 600 sf and over, plus a $75.00 residential permit application fee. Call Permits, Approvals and Inspections at 410-887-3900, the number listed on the county’s own roofing page, before you sign a contract if you are not sure how much sheathing the job will touch.

Howard County: 64 square feet of sheathing

Howard County’s building code, amended by Council Bill 24-2025 (the bill’s own effective-date clause sets it “61 days after its enactment”; our row dates that to September 7, 2025), exempts, on an existing single-family dwelling, “replacement of roof coverings with no other structural repairs” from a building permit, with an exception: up to 64 square feet of roof sheathing can be replaced as part of that exempt work. Go past 64 square feet of sheathing, or perform any other structural repair, and the job needs a building permit. The bill states the limit on that exemption in the same breath it grants it: exemptions under that subsection “do not apply to structures located in the floodplain.”

Howard’s fee schedule carries no roofing line item at all. For anything that crosses the sheathing line, the Department of Inspections, Licenses and Permits can be reached at 410-313-2455, option 4, the number the county’s permits page lists for “General Permits Related Information,” also printed on the fee schedule’s own letterhead.

Montgomery County: covering only, with a historic-property carve-out

Montgomery County’s home-improvement list, published for Building Safety Month 2026, names “Roof (covering only)” among the work you “most likely will not need a permit” for, alongside “Driveway on Property,” patios and window screens. That same list’s “Permits Required” side separately names “Exterior Work on Historic Property” among the work you “will likely need a permit” for, so a roof job on a historic property is a different question from the covering-only entry above, and the page itself warns that its list “does not include municipality and homeowner association rules and regulations.” Nothing past the covering material is on the no-permit list. Our row for the county, verified 2026-06-18, notes that structural modifications to the roof or changes involving fire resistance requirements would still need a permit, which the county’s own list implies by naming only the covering as exempt. If your job is anything other than swapping shingles or another covering material for new ones, call MC 311 at 240-777-0311, which the DPS page gives for exactly this question, or visit the DPS lobby at 2425 Reedie Drive.

Prince George’s County: shingles versus sheathing, no number attached

Prince George’s County draws its line at the same layer Howard does, sheathing, but states it as a flat either-or rather than a square-foot allowance. The county’s own permit reference table, as captured 2026-06-09 (the live page returns a 403 in this environment), lists “Replace roof shingles (no structural repair involved)” as needing no permit and no plans, and “Replace roof sheathing” as needing a Building Permit with plans. There is no numeric threshold published here; the trigger is which layer of the roof you are working on, not how much of it. Our row for the county adds that the underlying exemption “does not apply to property classified as a historic site or inside the Chesapeake Bay Critical Area Overlay Zones.”

The county’s fee schedule, captured 2026-02-11 and effective March 2, 2025, routes “Roofing - Shingles & Plywood - Residential” to “Alteration/Repair without U&O - Exterior”: “Total Fee = Administrative Fee $66 + Building Permit Fee ($220 or 1% of Construction Cost, whichever is greater). Plus Technology Fee 10%.” DPIE’s main number is 301-636-2000.

The pattern underneath the four answers

Every one of these rules gates on the same idea from a different angle. Baltimore County and Howard both measure sheathing, one as a share of the roof and one as a flat square-foot number. Montgomery County and Prince George’s both draw the line at the material, covering versus structure, with no number attached at all. None of the four decides whether you need a permit by what the job costs or how old the roof is; Prince George’s does bring cost back in once a permit is required, pricing the building permit at 1% of Construction Cost where that exceeds the $220 floor.

That also means a true sentence in one Maryland county is not portable to the next one over. Montgomery County’s homeowners most likely need no permit for a straightforward re-roof; Baltimore County’s are reading a 50 percent sheathing test, under the same state code.

Before the old roof comes off

Find out how much sheathing or deck the job will actually replace before you sign anything. It is the fact that decides the answer in Baltimore County and Howard County, and a contractor cannot always tell you that number until the old roofing is off. Ask directly whether your property carries a special designation: a historic district or Landmarks List listing in Baltimore County, a floodplain location in Howard County, or, per our row, a historic site or Chesapeake Bay Critical Area location in Prince George’s, because each of those three carves that case out of its general exemption regardless of size. In Montgomery County, ask whether the job counts as “Exterior Work on Historic Property” on the county’s own list, since that alone will likely mean a permit no matter what the covering-only exemption would otherwise suggest. And where your county’s rule turns on “structural repair” rather than a number, as Montgomery County’s and Prince George’s do, ask the office to define that against your specific job rather than assuming a shingle-for-shingle swap clears it automatically.

The national roof replacement overview covers how these same trigger types, a dollar value, a percentage of the roof, or square footage, play out across the 137 jurisdictions we cover, including the places that require nothing at all. Each Maryland county’s own page carries its portal, its current fee schedule, and the phone number above: Baltimore County, Howard County, Montgomery County, and Prince George’s County.

Do You Need a Permit to Replace a Roof in Maryland? It Depends on the County: figures as of 28 Sep 2026, 137 jurisdictions. Now 148.