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DECKS GENERAL REQUIREMENTS: Page 1 1 CARROLL COUNTY BUREAU OF PERMITS AND INSPECTIONS RESIDENTIAL CODE COMPLIANCE GUIDELINES FOR DECKS Code Reference: Chapter 97, Code of Public Local Laws and Ordinances of Carroll County and The International Residential Code as adopted The following list of Code requirements is intended to assist you in complying with the Carroll County Building Code as adopted by Chapter 97, Code of Public Law and Ordinances of Carroll County, but does not encompass the entire Code. Failure to comply with all applicable Code requirements will result in a Notice of Violation and / or Stop Work Order until such violations are corrected. The approved set of building plans and the permit must be made available at the site for all required inspections. Decks shall not be used or occupied until final inspection and approval is obtained. Should you have any questions regarding these requirements, please call 410-386-2674 or 1-888-302-8978. Note: Please be aware that these guidelines are minimum requirements for inspection approval only GENERAL REQUIREMENTS: a. All lumber shall be identified as southern pine, grade #2 or better and shall be pressure-treated with an approved process and preservative in accordance with American Wood Protection Association standards. All lumber in contact with the ground shall be approved preservative treated wood suitable for “ground- contact”. b. Chemicals used in pressure treatment methods will prematurely corrode standard fasteners, hardware, and flashing when in contact with lumber. To combat corrosion, the following is required. • All screw and nails shall be hot-dipped galvanized or stainless steel. • All hardware (joist hangers, cast-in-place post anchors, etc.) shall be galvanized with 1.85 oz/sf of zinc (G-185 coating) or shall be stainless steel. Look for products such as “Zmax” from Simpson Strong-Tie or “Triple Zinc” from USP. • All fasteners and hardware used must meet the minimum load requirements for its intended use. c. All manufactured products shall be installed in accordance with the manufacturerer’s instructions. This includes connectors and span restrictions. d. Decks constructed according to this handout are not approved for future hot tub installations. e. Decks around or next to an above ground pool shall also comply with the pool barrier guidelines. f. It is the responsibility of the permit holder or the permit holder’s representative to notify the county when the stages of construction are reached that requires an inspection. Page 2 2 Required Inspections: • A footing, framing, and final inspection are required on all decks. • Footing inspections required PRIOR to the placement of concrete. • Framing inspection after all structure members are installed. • Final inspection when deck is complete. • Inspections are required by law. Failure to receive any and all inspections can result in the issuance of violations, in accordance with Carroll County Ordinance. FOOTERS: a. Minimum depth from finished grade to bottom of all footings shall be 30” or extend to solid bearing which ever is greater. b. Deck footings 3’-0” or less from an existing exterior house wall shall bear at the same elevation as the footing of the existing house foundation. c. Size- 4x4 and 6x6 post require minimum 18” diameter footer. All footers require a minimum of 10” concrete after the required inspection. Note: Deck footers with roofs and rooms installed on may need to be sized to carry the additional load. d. All footings shall bear on solid ground. Bearing conditions shall be verified in the field by the building inspector. e. Do not construct footings over utility lines, septic lines, drainage lines or any type of underground tank. Be sure to contact Miss Utility before digging. f. All post anchors shall be galvanized. Page 3 3 LEDGER ATTACHMENT REQUIREMENTS: a. Ledger shall be the same size or greater than the deck joist depth with a minimum of 2”x 8”. b. When attachment is made to the existing house band joist, the band joist shall be capable of supporting the new deck. If this cannot be verified or conditions at the house differ from the details herein, then a free-standing deck will be required. c. House siding must be removed prior to installation of the ledger board. Approved corrosion resistant flashing is required at any ledger board connection to the wall of all wood framed construction. Flashing to be installed behind ledger and a continuous drip edge flashing to be installed over top of the ledger. Flashing to be carefully installed to prevent water intrusion. d. Ledger shall not be connected to house overhang/cantilever or brick veneer for structural purposes. In such cases the deck shall be free-standing. e. Ledger shall not be connected to engineered wood products of less than 1” in thickness. Contractor shall verify house bandboard attachment before attaching deck ledger. Attachment to any engineered product must be installed per manufacturerer’s instruction if not covered in these guidelines or be installed as free standing. f. Ledger Board Fastener Requirements • Bolts and Lags shall be ―” diameter with washers. For joist spans up to 12’-0” install @ 16” oc. For joist spans exceeding 12’-0” install @ 10” oc. • For other ICC approved attachment fasteners, it is imperative that the fastener be used and installed per the manufacturerer’s specifications. Manufacturerer’s specifications must be on site at the time of inspection. (Size, Location and spacing requirements) • All fasteners shall be staggered from top to the bottom along the horizontal run • Lead anchors are prohibited SEE FIGURES BELOW FOR ATTACHMENT AND FASTENER SPACING Page 4 4 Page 5 5 POSTS: a. Post/columns shall be a minimum of 4x4’s or equivalent for heights up to 8’-0”, and 6x6’s or equivalent for heights over 8’-0”. Maximum 14’-0” in height. b. When post is not buried, secure post to footer with an approved pre-manufactured post base with anchor. c. Diagonal bracing is required when deck is free standing. See detail below. d. See “Beam Size and Maximum Spacing Between posts for Beams” on next page. Page 6 6 BEAMS: a. Post to beam connection shall be secured by the following methods: • 4x4 post to beam-use approved column/post cap. • 6x6 post to beam-notch post and secure to post with 2-1/2” diameter bolts. Attachment of beam to side of post is prohibited. b. All beam splices shall be located over top of bearing post. Splices between posts are PROHIBITED. c. Beam cantilever past post: • 2x6 beam – prohibited • 2x8 beam – 2’ maximum • 2x10 beam – 2’ maximum • 2x12 beam – 2’ maximum d. All headers and beams shall be fastened together at 16” oc. with 16d nails along the top and bottom horizontal run. e. See beam chart below for required beam size and post spacing. For joist framing from one side only. Deck Beam Spans Joist Spans (LJ) Less Than or Equal To: Species Size 4 6’ 8’ 10’ 12’ 14’ 16’ 18’ Southern Pine 2-2x6 7’-1” 6’-2” 5’-6” 5’-0” 4’-8” 4’-4” 4’-1” 2-2x8 9’-2” 7’-11” 7’-1” 6’-6” 6’-0” 5’-7” 5’-3” 2-2x10 11’-10” 10’-3” 9’-2” 8’-5” 7’-9” 7’-3” 6’-10” 2-2x12 13-‘11” 12’-0” 10’-9” 9’-10” 9’-1” 8’-6” 8’-0” 3-2x6 8’-7” 7’-8” 6’-11” 6’-3” 5’-10” 5’-5” 5’-2” 3-2x8 11’-4” 9’-11” 8’-11” 8’-1” 7’-6” 7’-0” 6’-7” 3-2x10 14’-5” 12’-10” 11’-6” 10’-6” 9’-9” 9’-1” 8’-7” 3-2x12 17’-5” 15’-1” 13’-6” 12’-4” 11’-5” 10’-8” 10’-1” 4-Beam depth must be equal to or greater than joist depth if joist hangers are used. Page 7 7 FLOOR JOIST: a. See span table below for treated lumber, southern yellow pine, 40 psf live load, 10 psf dead load and deflection of L/360 minimum. b. Maximum cantilever/overhang = 2x6 prohibited, 2x8’s allowed 2’ maximum, 2x10’s and 2x12’s ( 16” oc.) allowed 3’ maximum. c. Cantilevered floor joist shall extend back towards the building at least three times the length of the cantilevered section. d. See detail next page for framing at chimneys or bay window. e. Where supported by attachment to an exterior wall, decks shall be positively anchored to the primary structure and designed for both vertical and lateral loads as applicable. NOTE: Such attachment shall not be accomplished by the use of toe nails or nails subject to withdrawal. f. See chart below for allowable joist spans. Size in Inches Spacing in Inches No. 1 No. 2 2x6 12" 10'-7" 10'-4" 16" 9'-7" 9'-5" 24" 8'-5" 7'-10" 2x8 12" 13'-11" 13'-8" 16" 12'-8" 12'-5" 24" 11'-1" 10'-2" 2x10 12" 17'-9" 17'-5" 16" 16'-2" 15'-10" 24" 13'-5" 13'-1" 2x12 12" 21'-7" 21'-2" 16" 19'-8" 18'-10" 24" 16'-1" 15'-5" Page 8 8 Page 9 9 DECKING BOARDS: a. All decking material shall be composed of dimension lumber (2” nominal thickness) or span rated decking in accordance with the American Lumber Standards. In either case, the use of decking boards wider than 6 inches is not recommended because of the “cup”, a form of wrap that can become a problem. See chart below for allowable spans. Note: Reduce the allowable decking spans if the decking is applied diagonally by installing the floor joist closer together, e.g.: 24” to 16” oc., and 16”to 12” oc. All composite decking shall be installed per manufacturer’s requirements. SPECIES MATERIAL SIZE MAX. JOIST SPAN Douglas Fir, Southern Pine, 5/4” 16” oc. Hem-Fir, SPF, SPF(south) 2x4 24” oc. Ponderosa Pine, Redwood, 2x6 24” oc. Western Cedar ♦Remember to reduce joist spacing if decking is applied diagonally♦ 24” to 16” and 16” to 12” GUARD POST: a. The guardrail posts can be attached to the exterior of the rim joist, or the interior of the rim joist. (see details on next page) b. Maximum post spacing for wood shall be 6’-0”. (see details below) c. NOTCHING OF POST NOT ALLOWED. d. Post shall be installed with a minimum of two (2) half inch bolts or ICC approved fasteners installed per manufacturerer’s instructions. Page 10 10 GUARDRAILS: a. Guardrails for porches, decks, balconies, or raised floor surfaces more than 30” above floor grade shall be 36” high. • See details below on guardrail height measurement and fixed seating. b. Open sides of stairs with total rise of more than 30” above floor or grade shall have guardrails not less than 34” high measured vertically from nose of tread. c. Horizontal spacing between vertical members in required guardrails shall be a maximum of 4 inches. Stairway guard spacing is 4-3/8” maximum. d. Triangular openings formed by riser, tread, and bottom rail of guardrails on stairways shall not allow a sphere 6” in diameter to pass through. e. Installation of wood/plastic composites shall be installed in accordance with the manufacturerer’s instructions. Page 11 11 Page 12 12 STAIRS AND HANDRAILS: a. Minimum 3 feet net clear width. b. Maximum riser height shall be 7 ¾ ”. c. Minimum tread width shall be 10” (measure from edge of nose to edge of nose). d. A nosing not less than ū” but not more than 1 ū” shall be provided unless tread width is 11” or greater. e. Riser and tread shall be consistent to within a tolerance of 3/8” throughout the flight. f. Risers shall not permit the passage of a 4” sphere. g. All stringers shall be a minimum of 2x12 material. h. Maximum stringer span for southern pine is 7’-0”. • If stringer span exceeds 7’-0”, midpoint support with frost footers shall be provided. • Post will require a 12” diameter footer. • Stringer shall be bolted to post with two ―” bolts with washers. • If the total vertical height of the stairway exceeds 12’-0”, then an intermediate landing shall be required. All intermediate stair landings must be designed and constructed as a free-standing deck with required frost footers. • Stairs shall be solidly attached to landings and deck. The cut for stair stringers or stair carriages shall be solidly attached for the entire height of the cut. See detail on next page for stringer attachment. i. The maximum allowable spacing of stair stringers or stair carriages shall be determined by the maximum allowable span of the tread material or decking used. • If cut stringers are used, a minimum of (3) three are required for 36” width stairs. • Check manufacturer of decking for additional stringer requirements. j. Stair guard height shall be a minimum of 34” measured from the nosing of step. k. Openings on required stair guards on the sides shall not allow a sphere of 4-3/8” to pass. l. Triangular openings formed by riser, tread, and bottom rail of guardrails on stairways shall not allow a sphere of 6” to pass. m. All stairs with 4 or more risers shall have a graspable handrail on at least one side. • Handrails shall be installed at 34”-38” measured vertically from the nosing. • All handrails shall run continuously from a point directly over the lowest riser to a point directly over the highest riser and shall return to the post at each end. • The minimum clearance from guards and post to handrail shall be 1-1/2”. • Handrails shall be graspable and be composed of decay-resistant and/or corrosion resistant material. Maximum cross dimension shall be 3-1/4”. n. Where the stairway meets the grade, the stringers shall bear on solid material such as concrete or patio blocks to provide support and protection of the stair stringers or each bottom rail post shall be encased in concrete. • All material in contact of ground must be ground contact approved. SEE NEXT PAGE FOR STAIRS AND HANDRAIL DETAILS Page 13 13
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http://ccgovernment.carr.org/ccg/permits/decks.pdf
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