Montgomery County, Ohio - Building Regulations Division

Montgomery County, Ohio. The County states its own reach as "the citizens and users of buildings in many of the jurisdictions in Montgomery County, including all of the townships and several of the cities and villages." That is deliberately not a list, and this record does not turn it into one: all townships are covered, but which cities and villages are covered is not published here, so confirm the specific address with the Division before bidding.

county

Dayton, OH

Residential Code of Ohio, Ohio Administrative Code Chapter 4101:8, effective July 1, 2019. Ohio adopts its residential code as a statewide administrative rule rather than leaving the edition to each jurisdiction: the Ohio Board of Building Standards promulgates it under Ohio Revised Code section 3781.10 and it governs one, two and three family dwellings throughout the state. Roof assemblies are Chapter 4101:8-9-01, and its section numbers carry no "R" prefix, so the reroofing rule is section 908 and the asphalt shingle rules are section 905. Ohio law does permit a local authority to add to the state code where the addition does not conflict: Ohio Revised Code section 3781.01(B) provides that the state residential building code "does not prevent a local governing authority from adopting additional regulations governing residential structures that do not conflict with the state residential building code," subject to a Board of Building Standards conflict review. The Division publishes no roofing amendment of its own among its building pages, so the state rules below are what governs a reroof in the areas it covers.

Not required — Ohio does not prescribe a drip edge, which is a real departure from the model code the rest of the state code follows. The International Residential Code sets a drip edge requirement at R905.2.8.5 with dimensions, an overlap and a fastening schedule. Ohio replaced that text entirely, and the whole of Residential Code of Ohio section 905.2.8.5 now reads: "Drip edge. Refer to Sections 903.1 and 905.1." Neither of those sections carries drip edge language of its own; what they do is make the manufacturer's instructions binding. Section 903.1 requires roof assemblies to "be designed and installed in accordance with this code and the approved manufacturer's instructions," and section 905.1 that "Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer's installation instructions." So the state code imposes no drip edge of its own, while the shingle manufacturer's published installation instructions do carry code force, and most asphalt shingle instructions require one. Omitting a drip edge against those instructions remains a violation in Ohio, by way of 903.1 and 905.1 rather than by way of a drip edge section. About drip edge

Required — Required, and required across the whole state rather than in a mapped zone. Residential Code of Ohio section 905.1.2 conditions the ice barrier on a local history of ice damming "as designated in Table 301.2(1)", and Ohio's own Table 301.2(1) makes that designation statewide: the ICE BARRIER UNDERLAYMENT REQUIRED column reads "Yes", and note h to the table states that "all jurisdictions in Ohio have a history of local damage from the effects of ice damming." There is therefore no per-city determination to look up. The barrier "shall consist of not fewer than two layers of underlayment cemented together, or a self-adhering polymer-modified bitumen sheet shall be used in place of normal underlayment and extend from the lowest edges of all roof surfaces to a point not less than 24 inches (610 mm) inside the exterior wall line of the building," measured along the slope from where the projected outside face of the wall meets the deck. On roofs of 8:12 or steeper it "shall also be applied not less than 36 inches (914 mm) measured along the roof slope from the eave edge." One exception travels with it: "Detached accessory structures and roof assemblies terminating at a vertical wall over unconditioned floor areas." It applies to asphalt shingles, metal roof shingles, mineral surfaced roll roofing, slate and slate-type shingles, wood shingles and wood shakes. About ice & water barrier

Not required

115 mph ultimate design wind speed, set statewide. Ohio fills in the wind column of Table 301.2(1) of the Residential Code of Ohio once for the whole state rather than leaving it to each jurisdiction, and the WIND DESIGN Speed (mph) entry is 115. Exposure category is not fixed by the table; note d directs that "Wind exposure category shall be determined on a site-specific basis in accordance with Section 301.2.1.4." Ohio has struck three of the model table's wind entries outright, recorded in notes k, l and m: topographic wind speed-up effects, unusual wind conditions and wind-borne debris zones are all deleted, so no wind-borne debris protection applies in Ohio. For the shingles themselves, section 905.2.4 sets wind resistance by ASTM D7158, with an exception that "Asphalt shingles not included in the scope of ASTM D7158 shall be tested and labeled in accordance with ASTM D3161." Both are wind standards; neither speaks to impact.

Two total layers. The default is a full tear off and a recover over one existing layer is the exception; a recover over two or more layers is not allowed. Residential Code of Ohio section 908.3, Roof replacement: "Roof replacement shall include the removal of existing layers of roof coverings down to the roof deck," with an exception permitting an existing ice barrier membrane adhered to the deck to stay and be covered with an additional layer of ice barrier membrane. Section 908.3.1 then permits a recover in four listed situations, the first being where the new covering is installed in accordance with the roof covering manufacturer's approved instructions. Section 908.3.1.1, Roof recover not allowed, sets the bar: "A roof recover shall not be permitted where any of the following conditions occur: 1. Where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing. 2. Where the existing roof covering is slate, clay, cement or asbestos-cement tile. 3. Where the existing roof has two or more applications of any type of roof covering." Ohio's rule has three conditions and none is a hail exposure condition, so unlike the older model code editions still in force in some states there is no case here in which a single existing layer must come off on hail grounds alone. Under section 908.5 aggregate surfacing "shall not be reinstalled," and existing flashings, edgings, outlets and vents "shall be replaced where rusted, damaged or deteriorated."

Solid sheathing is required under asphalt shingles. Residential Code of Ohio section 905.2.1, Sheathing requirements: "Asphalt shingles shall be fastened to solidly sheathed decks." Ohio states this without the plank-width alternative some states write in, so spaced or skip sheathing will not carry an asphalt shingle roof here. Section 908.2 additionally requires that the structural roof components "be capable of supporting the roof covering system and the material and equipment loads that will be encountered during installation," and section 908.3.1.1 bars a recover over a deck that will not serve as a base, which is the provision that catches deteriorated sheathing found once the old covering is off.

7.50% combined, which is the Ohio state rate of 5.75% plus a Montgomery County rate of 1.75%. Ohio levies its local sales tax at the county level and has no separate municipal add-on, so the same 7.50% applies throughout Montgomery County and there is no city or village component to add. Read from the Ohio Department of Taxation's own Sales and Use Tax Rates by County table, county code 57. That published table is the one effective October 1, 2026, and it marks a changed county with an asterisk against the county name; Montgomery carries no asterisk and Warren is the only Ohio county that changes on that date, so 7.50% is also the rate in force now.