Building Code Adoption

The Calvert County Department of Planning & Zoning, Division of Inspections and Permits and the Calvert County Building Board recommended the Calvert County Board of County Commissioners (BOCC) adopt the 2018 International Building Code (IBC) and 2018 International Residential Code (IRC) as the Calvert County Building Code during a public hearing held Tuesday, May 17, 2022. 

The BOCC voted to adopt the IBC and the IRC as the Calvert County Building Code, effective July 1, 2022.  The Calvert County Building Code establishes requirements for making an application and for permit issuance; time limits of applications and permits; and provisions for serving notices of violations and violation penalties. It also provides regulations of commercial and residential building in Calvert County, including the construction, repair and demolition of building projects.  

Calvert County Building Code changes include, but are not limited to:

  • Requirements for roof access and pathways for firefighters for houses with rooftop solar panels
  • Guard handrail requirements now only apply to the specific portion of a walking surface that exceeds 30 inches above grade
  • Smoke alarms physical interconnection is not required where listed wireless alarms and all alarms sound upon activation of one alarm
  • Increases required R-values of insulation in walls and ceilings
  • Not less than 90% of the installed lighting fixtures shall contain high-efficacy lamps
  • Fuel gas lighting systems shall not have continuously burning pilot lights
  • A dwelling unit shall be tested and verified as having an air leakage rate not exceeding three air changes per hour to demonstrate the building’s air tightness

For additional information, please contact the Division of Inspections and Permits at 410-535-2155. View additional changes in the table below:

2018 IRC Update 

Chapter 1: Scope and Administration

Code Section 2018Section TitleDescription of Change
Modification R101.2 ScopeAll instances where the International Building Code (IBC) permits construction under the IRC are now listed in the exception to the scope of the IRC. 
Clarification R105.1, R110.1, R202 Change of Occupancy A definition for “Change of Occupancy” has been added and the requirement for a certificate of occupancy when there is a change of occupancy or use has been clarified. 

Chapter 3: Building Planning 

Code Section 2018Section TitleDescription of Change
Modification R301.2.2.1 Seismic Design Category New seismic design category (SDC) maps are included in the 2018 IRC. 
Modification R302.1 Exterior Walls References to the International Building Code (IBC) offer additional options and provide flexibility in determining the fire resistance rating of exterior wall assemblies. Table footnotes have been revised to clarify the correlation between gable end vents and the fire resistance requirements for projections. 
Modification R302.2 Townhouse Separation Two paths for achieving the fire-resistant separation between townhouse dwelling units – two 1-hour walls or a common wall – are spelled out in the townhouse provisions. 
Modification R302.13 Fire Protection of Floors above Crawl Spaces Fire-resistant membrane protection is now required for the applicable floor framing materials above crawl spaces containing fuel-fired or electric-powered heating appliances.
Modification R308.4.2 Glazing Adjacent to Doors Glazing within 24 inches of the hinge side of an in-swinging door now requires safety glazing where the glazing is at an angle less than 180 degrees from the plane of the door. 
Modification R308.4.4 Glazing in Guards and RailingsUnless laminated glass is used, structural glass baluster panels in guards now require an attached top rail or handrail. 
Clarification R308.4.7 Glazing Adjacent to the Bottom Stair Landing Figure R308.4.7 has been replaced with a new figure and the caption modified to more accurately reflect when safety glazing is required near the bottom landing. 
Modification R310.3 Area Wells for Emergency Escape and Rescue Doors For emergency escape and rescue doors in basements, a change in terminology replaces “bulkhead enclosures” with “area wells” and provisions for ladders and steps for area wells are added. 
Modification R311.7.1, R311.7.8 Handrail Projection A new exception to the handrail projection limitation provides for adequate clearance behind the handrail when it passes the projection of a floor, landing or tread return. 
Modification R311.7.3 Maximum Stair Rise between Landings The maximum rise of a flight of stairs has increased by 4 inches, from 147 to 151 inches. 
Modification R311.7.11, R311.7.12 Alternating Tread Devices and Ships Ladders Alternating tread devices and ships ladders are now permitted as a means of egress for lofts with an area that does not exceed 200 square feet. 
Clarification R312.1 Guards The guard requirements only apply to the specific portion of a walking surface that exceeds 30 inches above grade. 
Modification R314Smoke Alarms The exemption for interconnection of alarms during alterations based on feasibility has been removed from the code. 
Modification R315Carbon Monoxide Alarms Interconnection is now required where multiple carbon monoxide alarms are required in a dwelling unit. 
Modification R322.3 Coastal High-Hazard Flood Zones In coastal high-hazard areas (V Zones) and Coastal A Zones, the IRC now provides specific guidance for the design and construction of concrete slabs, stairs, guards, decks and porches to reduce damage to the dwelling in a flood event. 
Addition R324.6 Roof Access for Photovoltaic Solar Energy Systems Requirements for roof access and pathways for firefighters have been introduced into the IRC provisions for rooftop mounted photovoltaic solar energy systems. 
Addition R324.6.2.2 Solar Panels near Emergency Escape and Rescue Openings Rooftop mounted photovoltaic solar energy panels and modules are not permitted to be installed below emergency escape and rescue openings. 
Modification R325.3 Mezzanine Area Limitation The area limitation for mezzanines has been increased from one-third to one-half of the area of the room containing the mezzanine under certain conditions. 
Addition R325.6, R202 Habitable AtticsThe definition of habitable attic has been revised and the technical requirements have been placed with mezzanines. 

Chapter 4: Foundations

Code Section 2018Section TitleDescription of Change
Modification Table R403.3(1) Insulation requirements for frost protected footings Insulation thickness requirements for Type II and IX extruded polystyrene (EPS) have changed. The minimum R-value for specific types of EPS has been clarified while requirements for horizontal insulation were added. 
Modification Table R403.4 Crushed stone footings Table R403.4 is updated to include both the minimum depth and width of a crushed stone footing for a precast concrete wall. 
Modification R408.3 Unvented crawl spaceVentilation of the under-floor space is not required when an adequately sized dehumidifier is provided. 

Chapter 5: Floors

Code Section 2018Section TitleDescription of Change
Modification R507 Decks Section R507 is reorganized for ease of use and additional provisions are added to simplify prescriptive construction of a deck. 
Modification R507.2 Deck materials Section R507.2 adds requirements for fasteners and fastener connections, flashing and alternative materials. 
Addition R507.3 Deck footings A new section on footing minimum size is added to help describe minimum prescriptive (non-engineered) requirements for an exterior deck footing based on snow load, soil quality, and footing shape and size. 
Clarification R507.6 Deck joists Maximum joist spacing and total length have been clarified. In Table R507.6, maximum span length is listed followed by maximum cantilever length. 
Clarification R507.7- R507.9Decking, Vertical and Lateral Support Decking material options and fastener systems are clarified. Vertical and horizontal support of an exterior deck is updated while support and attachment of ledgers is added to the decking section. 

Chapter 6: Wall Construction 

Code Section 2018Section TitleDescription of Change
Modification R602.10.4.1 Mixing bracing methods Mixing of continuous sheathing methods with an intermittent alternate bracing method is clarified. Braced wall line(s) containing an alternate method must have sufficient bracing length for an intermittent method, not just for the continuous sheathing method when the alternate method is Method PFH, PFG or ABW. 
Modification R602.10.6.5 Method BV-WSP An attempt to clarify use of the BV-WSP method is made. New limits are added to Section R602.10.6.5. 
Modification Tables R603.3.1, R603.3.1.1 (2) Cold-Formed Steel Wall Construction Cold-formed steel connection tables are updated for wind speeds less than 140 miles per hour. Values in the IRC tables now match AISI S230, Standard for Cold-Formed Steel Framing - Prescriptive Method for One-and Two-Family Dwellings. 

Chapter 7: Wall Covering 

Code Section 2018Section TitleDescription of Change
Modification R703.2 Water-resistive barrierWater-resistive barrier materials other than No. 15 asphalt felt must be installed following the manufacturer’s installation instructions. The exemption for detached accessory buildings is deleted. 
Modification R703.3.1 Soffit installation Requirements for wood structural panel soffits are added to Section R703.3.1 and vinyl soffit requirements are clarified. 
Modification R703.8.4 Veneer anchorage through insulation Masonry veneer is explicitly allowed to attach to through insulation into the underlying wood structural panels. Attachment must follow Table R703.8.4(2). 
Modification R703.11.2 Vinyl siding installation over foam plastic sheathing New Table R703.11.2 gives design wind pressures for vinyl siding resisting all wind loads without reliance on wood structural panel sheathing.

Chapter 8: Roof-Ceiling Construction 

Code Section 2018Section TitleDescription of Change
Modification R802 Roof Framing Section R802, Design and construction of roofs, has been clarified by dividing the content into three separate sections on roof ridges, rafters and ceiling joists. 
Modification R802.1.5.4 Labeling Each stick of fire-retardant-treated lumber and individual wood structural panel will be labeled with eight specific items of information.
Modification R806.2 Minimum vent area The minimum vent area exception is clarified, stating that net free ventilation may be less than 1/150 only if two required conditions are met. Lower vents must be located in the bottom third of the attic space. 

Chapter 9: Roof Assemblies

Code Section 2018Section TitleDescription of Change
Addition R905.17 Building Integrated Photovoltaic Panels New Section R905.17 addresses installation and attachment of building integrated photovoltaic (BIPV) roof pane 

Chapter 10: Chimneys and Fireplaces 

Code Section 2018Section TitleDescription of Change
Addition R1005.8 Chimney insulation shield Factory-built chimneys, which have been required to maintain a minimum clearance to insulation, are now required to have an insulation shield to provide the clearance to the insulation. 

Chapter 11: Energy Efficiency 

Code Section 2018Section TitleDescription of Change
Clarification N1101.6, Tables N1101.10.3 (1) and N1101.10.3 (2) Fenestration Definitions and U-Factors The definitions for skylights and vertical fenestration have been moved under the definition for fenestration, and a definition for opaque door has been added. 
Modification N1102.1 Building Thermal Envelope for Log Homes Log homes are now exempt from the prescriptive building thermal envelope requirements when designed in accordance with ICC-400, Standard on the Design and Construction of Log Structures. 
Modification N1102.1.2 and N1102.1.4 Insulation and Fenestration Requirements The prescriptive U-factors for fenestration have been lowered to improve the energy efficiency of dwellings and townhouses. 
Modification N1102.2.2 Reduction of Ceiling Insulation When applying the exception for insulation in ceilings without attics, the insulation must extend to the outside of the top plate. 
Clarification N1102.2.5 Mass Walls The mass wall provisions have been itemized in a numbered list to bring accuracy and clarity to the technical requirements. 
Modification N1102.2.6 Cold-Formed Steel Framing R-Values Conflicting entries have been removed from the table establishing cold-formed steel R-values equivalent to those for wood framing. 
Modification N1102.4 Testing for Air Leakage A new standard for air-leakage testing, RESNET/ICC 380, is now referenced in the IRC to provide flexibility for the testing industry. 
Addition N1103.3.6 and N1103.3.7 Ducts Buried within Ceiling Insulation New provisions address the methods, minimum coverage requirements and thermal benefits for ducts buried within ceiling insulation, and when those ducts are considered inside the building thermal envelope. 
Modification N1104.1 Lighting The required percentage of permanent lighting fixtures having high-efficacy lamps has increased from 75 to 90 percent. 
Modification N1106.3, N1106.4 Maximum Energy Rating Index The maximum rating index values based on climate zone have increased slightly to make the ERI provisions less restrictive and improve the flexibility of the energy provisions.