Subdivision 4. Amendments to the International Residential Code for One- and Two-Family Dwellings

Chapters 25-33 of Part VII - Plumbing are hereby deleted and replaced with the Plumbing and Gasfitting Regulations adopted by the Washington Suburban Sanitary Commission (WSSC), known as the WSSC Plumbing and Fuel Gas Code.

Chapters 34 through 43 of Part VIII - Electrical are hereby deleted and replaced with Subtitle 9 of the County Code.

Section R112.2 is hereby amended to read as follows: Limitations on Authority. An application for appeal shall be based on a claim that the true intent of this code or the rules legally adopted thereunder have been incorrectly interpreted, the provisions of this code do not fully apply or an equally good or better form of construction is proposed. The board shall not have authority to waive requirements of this code and shall not have jurisdiction over matters for which adjudication or appeal is expressly assigned to the procedures outlined in Section 13, Division 15 of this Code.

Properties where the structure is being razed and where a new structure is being constructed will be considered new single family dwelling units and will be subjected to applicable public safety and school surcharges as defined by the Fee Table in Section 2-253.63.

Where roof surfaces adjacent to the wall or walls are at the same elevation, the parapet shall extend not less than thirty (30) inches above the roof surfaces; and

Where roof structures adjacent to the wall or walls are at different elevations and the higher roof is not more than thirty (30) inches above the lower roof, the parapet shall extend not less than thirty (30) inches above the lower roof surface.

A parapet is not required where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is more than thirty (30) inches above the lower roof. The common wall construction from the lower roof to the underside of the higher roof deck shall not have less than a one (1) hour fire-resistive rating. The wall shall be rated for exposure from both sides.

All new one- and two-family dwellings and town homes up to 3 stories in height with private garages and carports shall have a 1 hour fire barrier/separation with 45 minute door and heat detector.

"Locations." Every door which opens directly from any one or two-family dwelling to the outdoors; fifty percent (50%) of the nominal area of every double-hung and horizontal sliding window, and that portion of every other type window normally used for ventilation; and all other openings, unless specifically exempt or modified by the Building Official in accordance with the hardship or modification provisions of this Subtitle and the IRC, shall be screened with not less than sixteen (16) mesh per inch material. In addition, every hinged screen door shall have a self-closing device in good working condition. Screen doors shall not be required on the main entrance door.

"Governing Code." Screens required by this Section shall be installed or be available to be installed on all dwelling units. The actual times that screens must be provided and installed for use on all dwellings will be governed by the Prince George's County Housing Code. These provisions shall be applicable to all dwelling structures irrespective of the date of construction.

M1503.6. Makeup air required. Exhaust hood systems capable of exhausting more than 400 cubic feet per minute (0.19m 3 /s) shall be mechanically or naturally provided with makeup air at a rate approximately equal to the exhaust air rate in excess of 400 cubic feet per minute. Such makeup air systems shall be equipped with not less than one damper. Each damper shall be a gravity damper or an electrically operated damper that automatically opens when the exhaust system operates. Dampers shall be accessible for inspection, service, repair and replacement without removing permanent construction or any other ducts not connected to the damper being inspected, serviced, repaired or replaced.

Building Permits:

Mechanical Permits:

Electrical:

Repairs/Replacement Permits:

A permit under which no work has commenced and an inspection has not been performed within one hundred eighty (180) days after issuance shall expire and become null and void; provided, however, that the Director or the Director's designee may extend the time herein not to exceed an additional one hundred eighty (180) days upon sufficient justification shown.

A permit under which work has been started and later suspended or discontinued shall expire and become null and void six (6) months after the work has stopped. Work will be considered suspended or discontinued when the builder fails to prosecute the work so as to ensure completion within a reasonable period of time considering the type of construction involved. The Director or the Director's designee may extend the time herein not to exceed an additional twelve (12) months upon sufficient justification shown.

A permit issued in error or not in compliance with County Code at time of issuance may be suspended by the Director or the Director's designee.

When a permit has expired for failure to commence work, it may be renewed within a period of thirty (30) days from the date of expiration if the conditions under which the permit was originally issued have remained unchanged and there has been no change in law or ordinance that would adversely affect the permit. A fee shall be collected for each renewal; however, no permit may be renewed more than two (2) times.

Whenever the Director or the Director's designee determines by inspection that work started on any building or structure for which a permit has been issued has been suspended for a period of six (6) months, the owner of the property upon which the structure is located, or other person or agent in control of said property, shall, within thirty (30) days from the receipt of written notice from the Department, obtain a new or renewal permit to complete the required work and diligently pursue the work to completion, or shall remove work not completed or demolish the incomplete structures or buildings within sixty (60) days from the date of the printed notice.

Permits suspended for failure to comply with the County Code or ordinances may be reinstated by the Director or the Director's designee upon compliance or approved validation.

A permit issued for property within the area of a pending Sectional Map Amendment, as provided for in Subtitle 27 of this Code, that is rezoned to a less intense zone, shall expire if a completed building foundation for a use not permitted in the less intense zone has not been constructed pursuant to a validly issued permit prior to District Council approval of the Sectional Map Amendment. The determination of the Director or the Director's designee made in accordance with Subsection R105.5.1 of this Subtitle shall not be appealable to the Board of Appeals.

The Director or the Director's designee may reissue a permit subject to all applicable laws or regulations in effect at the time the permit was originally issued, for a period not to exceed one (1) year after expiration provided that:

Applicable Codes. The laws and regulations in force on the date that a new edition of the Construction Codes are adopted pursuant to the sections below.

Existing Valid Permit. Work authorized by a permit issued before the effective date of the new edition of the Construction Codes shall be allowed to be carried to completion, subject to the conditions of Sections R105.5 and R105.6.

Existing Filed Application. Applications for permits for which the application filing deposit has been paid before the effective date of the new edition of the Construction Codes shall be allowed to be processed to issuance of the permit, and any work authorized thereby shall be allowed to be carried to completion, under the edition of the Construction Codes in effect on the date said applications were filed, subject to the following conditions:

Existing Design Contracts. Buildings and other structures under contract for design on the effective date of the new edition of the Construction Codes, for which no permit applications have been filed, shall be allowed to be filed, processed to issuance of permit, and any work authorized thereby shall be allowed to be carried to completion, under the previous edition of the Construction Codes, subject to the following conditions:

Violations or Infractions. The laws and regulations in force on the date that a new edition of the Construction Codes is adopted and shall apply with respect to violations or infractions committed prior to said date, whether the prosecutions or adjudications of those violations of infractions are begun before or after said date.

A basement exit to grade is not required;

A second exit from the dwelling is not required;

Trusses are not required to be provided with a fire-resistive ceiling membrane; and

Fire separations may be reduced from two (2) hours to one (1) hour rating and may be constructed with combustible framing. The one (1) hour rated fire separation wall need not be able to withstand collapse of construction on either side under fire conditions.

Circuit breaker switch must be within the visual line-of-sight of the pump. A sub-panel may be provided within the line-of-sight of the pump, if the main panel is in a remote location to the pump.

Passive electrical supervision to the pump will be accomplished through the following wiring diagram of either the main or subpanel. See figure R-328.6.1.

Circuit breaker switch must be within the visual line-of-sight of the pump. A sub-panel may be provided within the line-of-sight of the pump, if the main panel is in a remote location to the pump.

Passive electrical supervision to the pump will be accomplished through the following wiring diagram of either the main or subpanel. See figure R-313.6.1.

Circuit breaker switch must be within the visual line-of-sight of the pump. A sub-panel may be provided within the line-of-sight of the pump, if the main panel is in a remote location to the pump.

Passive electrical supervision to the pump will be accomplished through the following wiring diagram of either the main or subpanel. See Figure R-313.6.1

Wall or floor mounted;

Accessible for inspection or service;

Ensure not located in hazardous area;

Install as per manufacturer's requirements.

Where roof surfaces adjacent to the wall or walls are at the same elevation, the parapet shall extend not less than thirty (30) inches above the roof surfaces; and

Where roof structures adjacent to the wall or walls are at different elevations and the higher roof is not more than thirty (30) inches above the lower roof, the parapet shall extend not less than Thirty (30) inches above the lower roof surface.

A parapet is not required where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is more than thirty (30) inches above the lower roof. The common wall construction from the lower roof to the underside of the higher roof deck shall not have less than a one (1) hour fire-resistive rating. The wall shall be rated for exposure from both sides.

At a minimum, every other vertical reinforcement shall have a footing dowel or use engineer design per IRC code. The lap length at the top of the footing shall be adequate to develop the full tension capacity of the reinforcement.

Footing design shall be based on minimum soil load bearing capacity of 1,500 psf. See IRC Table 403.1(1) to 403.1(3). Footings in accordance with the engineering design are acceptable if a geotechnical report including the soil load bearing capacity is provided for each lot.

Section R-403.1.4, Minimum Depth. All exterior footings and foundation systems shall extend below the frost line. The bottom of all exterior footings shall be placed at thirty (30) inches below the finished grade.

Section R-403.1.6, "the maximum spacing of one-half (½) inch diameter anchor bolts is amended to be four (4) feet."

Section R-403.2, titled "Footings for wood foundations" is deleted.

Section R-404.1.1, Design Loads. In addition to other applicable loads, the basement walls shall be designed for the at-rest pressure (lateral soil load) as described in Table 1610.1 of the 2021 International Building Code.

Section R-404.1.2, Design of Concrete Masonry. Design of concrete masonry unit (CMU) walls shall conform to the Building Code Requirements for Masonry Structures (ACI 530/TMS 402) Chapters 1, 2 and 3. Minimum horizontal joint reinforcement consisting of not less than two continuous wires each with a minimum cross-sectional area of 0.017 square inch (9 gage) shall be provided in horizontal bed joints spaced not more than every second course vertically. For basement walls subjected to lateral earth pressure, minimum vertical reinforcement shall consist of one No. 5 rebar (ASTM A615 grade 60) spaced not more than sixteen (16) inches (for nominal 8", 10" or 12" walls). Cells having vertical reinforcement shall be filled with concrete or masonry grout meeting the requirement of ASTM C476. Vertical steel reinforcement shall be placed not more than 2 inches from the inside face of the walls.

Section R-404.1.3, Design of Concrete Walls. Design of concrete walls subjected to lateral earth pressure shall conform to the Building Code Requirements for Reinforced Concrete (ACI 318) Chapter 10. Minimum reinforcement in each direction shall not be less than that required by Chapter 7 (i.e. for ASTM A615 grade 60, No. 4@14" for 8-inch thick, No. 4@12" for 10-inch thick, and No. 4@10" for 12-inch-thick wall). For design of concrete walls subjected to lightly loaded lateral earth pressure (4 feet or less of unbalanced backfill) or concrete walls with insignificant stress components (for example, stresses reduced by mean of wall stiffeners) the ACI 318 Chapter 22 may be used to determine the amount of reinforcement required. Engineered wall design is acceptable for wing walls per ACI-318 code.

The Height of a retaining wall is measured from lowest ground elevation on the lower or bottom side of wall to the highest elevation on the top of the retaining wall structure, at any given cross section of the wall.

Soil investigation is required at a minimum rate of one soil test boring per 100 linear ft of the retaining wall length.

Timber retaining walls are not allowed.

In general, on residential developments, the height of retaining walls shall be minimized preferably to less than 6 feet, for ease of maintenance. This also applies to the cumulative height of tiered retaining walls.

Retaining walls shall be located on common homeowner or business park association parcels, to the maximum extent practical. Retaining walls shall not be located in the public storm drain or storm water management easements. Retaining walls shall not be located in the County public road right of way, except for abutment walls for bridges.

For Segmental Retaining walls (SRW) including Mechanically Stabilized Earth Walls (MSEW) higher than 2 feet, and other proprietary products, the applicant shall include in the permit submittal the manufacturer's information and specifications, and a valid evaluation report from a DPIE approved listing agency. The permittee shall submit an acceptance letter for the geotechnical aspects only of the wall design from the Geotechnical Engineer of Record (GER) if the GER is not the wall designer.

Declaration of Easements for Retaining Walls

Retaining wall plans shall show wall drainage systems and select backfill behind the wall, filter fabric between the select backfill and adjacent soils, structural elements, and reinforcement type and size.

Retaining walls shall be designed to meet the minimum safety factor of 1.5 against sliding and overturning.

Retaining wall plans shall show in site plan view, wall profile view, and wall sections the extent of select backfill, soil reinforcement, filter fabric, and other pertinent information. The design professionals (structural, civil, geotechnical) shall fully coordinate select backfill and soil reinforcement with all site features.

Retaining walls shall be located with the toe of the wall a minimum of 25 feet from creeks, streams, and swales, as these locations have the potential for eroding and undermining retaining wall structures. The design engineer shall submit a scour analysis for streams and swales in close proximity to retaining walls. If the scour analysis requires, the retaining wall permit documents shall be designed with a foundation system capable of withstanding the scour, for example deep foundation system and/or armoring of the stream, as required.

Segmental retaining walls (SRWs), including the leveling pads, shall not be placed below the 100-year floodplain elevation, due to concerns with scour and migration of soil backfill.

For retaining wall permits, a global stability analysis shall be signed and sealed by a licensed geotechnical engineer and must be provided for the following conditions:

Retaining walls shall be drained by a system that includes:

Within the select backfill zone, the upper soil layer shall consist of 4 inches of topsoil and 12 inches of impervious clay soil or an impermeable geo-membrane below the topsoil. The purpose of this is to limit surface water infiltration into the select backfill zone of the retaining wall.

To prevent surface storm water from flowing over the top wall of wall, a swale is required immediately behind the wall. The swale may be located at least 12 inches behind the high side of the wall, with a depth of at least 6 inches. The swale shall have 4 inches of topsoil at the surface and 12" of impervious lean clay soil or an impermeable geo-membrane below the topsoil. If the length of land adjacent to and perpendicular to the wall is negligible, for example less than 5 feet wide, such that surface sheet flow down the slope and towards the wall is minimal, then the swale above the wall is not required. All concentrated flows shall be intercepted into a storm drain system and conveyed thru the wall.

If the groundwater elevation is 2 feet or less below the retaining wall leveling pad or is expected to rise seasonally to the bottom of the leveling pad or higher, a blanket drain is required below the retaining wall, near the bottom of the leveling pad.

If an identified water source such as groundwater or springs are located on the high side of a retaining wall, a drainage blanket and chimney drains at least 6" thick are required. The drainage blanket shall extend laterally from the wall to the chimney drain at a rising slope of 3%. The chimney drain shall rise to the elevation of the groundwater source, and shall have a heel drain pipe with a minimum four (4) inch diameter at its bottom. Blanket and chimney drains are also required if surface drainage runoff or subsurface water may otherwise flow to the wall, which frequently comes from unconfirmed or unidentified water sources. The blanket shall extend back from the wall to cover the entire select backfill and to reach the possible water source. The chimney height shall be seventy (70) percent of the wall height, with a heel drain pipe.

Soil reinforcement and/or other slope stabilization measures, such as caissons, piles, piers, deep dynamic compaction, or other means shall be shown to scale on the site grading plans in profile and plan views.

Retaining walls that retain multiple lots shall pass final inspection successfully before structures on all retained lots can receive final inspection.

Section R-405.1.2, Subsoil Drainage Systems. Subsoil drains shall be required for all buildings having basements, cellars, crawl spaces, or floors below grade. Subsoil drains shall be located inside and outside of the foundation and shall be installed at or below the area to be protected. Drains shall discharge by gravity or mechanical means into an approved drainage system.

Section R-405.2.3, Sump Pumps and Pits. Where subsoil drains do not discharge by gravity, the drains shall discharge to an accessible sump pit with an automatic electric pump. A battery back-up or water-powered back-up sump pump will also be provided. The sump pit shall be a minimum of twenty-four (24) inches in diameter or eighteen (18) inches square and twenty-four (24) inches in depth, and be provided with a fitted cover. The sump pump shall have adequate capacity to discharge all water coming into the sump as it accumulates but in no case shall the capacity of the pump be less than fifteen (15) gallons per minute. The discharge from the pump shall be a minimum of one and one-fourth (1¼) inches and shall have a union in the discharge piping to make the pump accessible for servicing. Subsoil drains and sump pump discharge may discharge to a properly graded open area provided the point of discharge is ten (10) feet from any property line or Building Restriction Line (BRL). Where a continuously flowing spring or high groundwater table is encountered during the design stage, basement floors shall be designed at least two and one-half (2.5) feet above the groundwater's highest detected level. Alternatively pre-approved methods of permanent dewatering shall be provided, and the groundwater level shall be verified again before construction. If such condition is encountered by the County and subsoil drains are pre-approved by the County; these drains must be piped to a storm drain or approved outfall where they shall be fitted. When piped to a storm drain all drainage lines shall include an accessible backwater valve. Residential sump pumps are not to be relied on for lowering high groundwater table.

Section R-405.1.4, Areaway Drains. All open subsurface space adjacent to a building serving as an exit or entrance shall be provided with a drain or drains. Such areaway drains shall be of approved material in accordance with Chapter 30 of this Code and not less than 2 inches in diameter and shall discharge by gravity or mechanical means in accordance with R-405.1.2. Areaway drains for areas exceeding 800 square feet shall be sized in accordance with Section 1113 of the 2021 International Plumbing Code.

Section R-405.1.5, Window Well Drains. Window well areaways shall have drains. Window well areaways 10 square feet or less may discharge to the subsoil drain through a 2-inch minimum diameter pipe. Drains for window well areaways greater than 10 square feet shall be installed in accordance with Section R-405.1.3.

Section R-405.1.6, Foundation Weep Holes. Where subsoil drains are required by Section R-405.1.1, foundations of hollow core masonry shall have foundation weep holes. Weep holes shall be placed a maximum of 4-foot o/c intervals and shall discharge into the aggregate of the interior subsoil drainage system.

Section R-405.1.7, Site Grading. The ground immediately adjacent to the foundation shall be sloped away from the building at a slope that conforms with the County Grading Code 32-151. Consideration shall be given to the possible additional settlement of the backfill when establishing the final ground level adjacent to the foundation.

Section R-405.2, titled "Wood foundations" is deleted in its entirety.

Section R-502.7. Floor joists adjacent and parallel to the exterior foundation wall shall be provided with full-depth solid blocking, not less than two (2) inches nominal in thickness, placed perpendicular to the joist at spacing not more than four (4) feet. The blocking shall be nailed to the floor sheathing, the joist and the exterior rim joist/board.

Buildings protected throughout, excluding crawlspaces less than forty-two (42) inches in depth by an automatic sprinkler system; and

Crawl spaces of not more than forty-two (42) inches in depth, measured from the top of the floor surface above to the surface of the crawl space floor.