EPDM roofing in Bethesda, MD: what the Maryland code text names and leaves out

What the code names for EPDM

Chapter 15 of the Maryland Building Code 2021, which adopts the International Building Code, has one section for single-ply roofing, 1507.12. It does not split EPDM into its own heading. EPDM appears as a row in a table, and the rest of the section applies to all single-ply membranes together.

Maryland Building Code 2021, chapter 15, as published by UpCodes, opened October 20, 2026. UpCodes is a third-party publisher, not the State.

The county’s Master List of Building Codes and Standards shows the 2021 International Building Code and the 2021 International Residential Code, both effective December 10, 2024. The county amendments were not read for this page, so ask DPS whether any change touches a roof covering.

The commercial text and the residential text

The residential text, the MBPS Residential Code 2021 as published by UpCodes, is the one that uses the word thermoset in a heading. It pairs EPDM’s standard with D5019, the standard the commercial table gives to chlorosulfonated polyethylene and polyisobutylene. Thermoplastic membranes such as TPO and PVC sit in the next section, R905.13, with their own standards.

Which text governs depends on the building type, and that is a question for the county or the design professional, not for this page. A townhouse and a high-rise are not read from the same chapter.

Ballast, wind and the test routes

SPRI, the single-ply trade association, notes in an August 2026 post that chapter 15 relies on those three test standards for uplift and that its Directory of Roof Assemblies lists tested low-slope assemblies. It also says to verify code adoption with the authority having jurisdiction.

Recover, tear-off and old parts

The roof-replacement questions on an existing EPDM roof land in section 1512 of the same chapter. Its lines work as a short decision path.

• First, the coating questionA new protective coating over thermoset or thermoplastic single-ply may be applied without tear-off of existing coverings.
• Second, a recover over the membraneA new covering over an existing one is permitted where installed under the maker’s approved instructions, and not where the exceptions below apply.
• Third, the three barsNo recover where the roof is water soaked or deteriorated as a base, where the covering is slate, clay, cement or asbestos-cement tile, or where it already has two or more applications of any covering.
• Fourth, the parts that stayExisting metal edgings, vent flashing and similar parts “shall not be reinstalled where rusted, damaged or deteriorated.”
• Fifth, the stone“Existing ballast that is damaged, cracked or broken shall not be reinstalled.”

Section 1512.5 adds that flashings are reconstructed under the maker’s approved instructions. The residential text has a matching recover section with the same coating line for thermoset and thermoplastic single-ply.

On permits, the county’s Residential Restore / Repair page describes a permit to restore or replace part of an existing building to maintain or correct damage, and the Home Improvements page says it does not include municipality or homeowner association rules. The Bethesda roofing guide lays out the permit lanes and the contractor license check.

Drains, scuppers and parapets

Fire class is the other number a flat roof file carries. The code sorts roof coverings into Class A, B and C under ASTM E108 or UL 790, and Table 1505.1 sets a minimum class by construction type. The chapter does not name EPDM in that section, so the class comes from the listing of the whole assembly, not from the membrane word on the quote.

Code lines to check in a Bethesda EPDM quote

• The slope, measured on site, against the 1/4 in 12 design slope in the text.
• The membrane standard cited on the product sheet: ASTM D4637 for EPDM.
• Whether the roof is ballasted, adhered or mechanically attached, since each has its own code route.
• For ballast, the stone standard (ASTM D448 or D7655) and the RP-4 design the weight comes from.
• The test or listing relied on: FM 4474, UL 580, UL 1897, or a fire class listing.
• What happens to old edge metal, flashings, drain outlets and ballast, part by part.
• The overflow route: scuppers or secondary drains, and where they sit on the parapet.
• Any written reply from DPS, the owner or the association the scope depends on.

Book a phone consultation to talk through a Bethesda EPDM roof. For the material in general see the EPDM roofing guide, roofing materials, flat roof, roof replacement and services. The Bethesda guide has the local permit and licensing path.