Walls, boring and notching of studs and joists, wall finishes
Wood or metal studs may be used. Non-bearing walls may be constructed of 2x4 or 2x3 studs spaced a maximum of 24 inches on center, or with 2x4 flat studs (long dimension of the stud parallel to the wall) spaced a maximum of 16 inches on center.
Utility grade studs are permitted for non-bearing walls up to a height of 10 feet. Non-bearing walls may be constructed with a single top plate. Exterior walls shall be of sufficient depth to accommodate a minimum R-9 insulation (minimum 2x4 studs walls and minimum R-13 insulation is recommended).
Wall Sole (Bottom) Plates
Wood sole plates which are not separated from the slab by an approved moisture barrier (such as a polyethylene plastic 6 mils or more in thickness) are required to be pressure treated or naturally decay resistant wood. Studs or other framing members in direct contact with a concrete foundation wall also are required to be pressure treated or naturally decay resistant wood.
Fasteners used in preservative treated wood (ACQ) should be hot dipped galvanized nails or other approved fasteners. Nailing schedule:
- Sole plates shall be attached to the floor with equivalent of 16d nail at 16” o.c. Some options include powder actuated fasteners, expansion anchors, and concrete nails.
- Top or sole plate to studs – 2-16d; toenails 3-8d or 2-16d
- Double studs face nail – 10d @ 24” o.c.
Fireblocking is a code mandated technique that would slow the spread of fire in a concealed location. Without it, a fire may spread rapidly, using the chimney effect to move up in concealed chases. Fireblocking is typically done with 2 inch thick nominal lumber, ¾ inch plywood, or fiberglass insulation. Fireblocking is required in concealed locations, such as walls, wall/ceiling interconnections with soffits, concealed stairs, and around pipes and other penetrations at the floor/ceiling level. Fireblocking is a frequently misunderstood requirement, but it's required in wood framed buildings.
Protection of wiring and piping from physical damage
Wiring and piping within walls must be protected from physical damage from nails and other objects driven into the studs and joists. Holes bored in joists and studs must be kept located to provide a minimum 1/1/4 inches of clearance for wires, such as type NM cable, and 1/1/2 inches for plumbing and water piping. Where the clearance is less the area shall be protected by a 1/16 inch plate to cover the area. For plumbing and water piping the plate shall extend a minimum 2 inches above sole plates and below top plates.
Cutting, boring and notching
Note: floor joists are structural members and should not be cut unless approved by the jurisdiction.
- Bored holes conventional wood framing
- Holes shall not be located closer than 2 inches from the top or
- bottom of joist.
- Successive holes shall be separated by not less 2 inches.
- The diameter of holes shall not exceed 1/3 the depth of the joist.
- Bored holes in engineered wood trusses and I-joists
- Hole placement shall follow the manufacturer’s installation instructions. Instructions should be available from the manufacturer’s web site or consult with the local jurisdiction. Never cut, notch or alter the top or bottom chord of the truss or I-joist.
Top of wall support / isolation
The tops of walls should be attached to the supporting framing above to provide lateral support. Overland Park requires a 1” isolation joint at the top of the wall (hold the wall below the bottom of the floor joists and beams) to minimize floor movement, caused by expansive soils, from being transferred to the first floor framing. Many houses are built on clay soils that are highly expansive. Soil expansion and contraction can cause the floor to move up and down even though the floor may not crack. If wall framing is tight to the floor above this up and down movement can result in similar up and down movement of the floor and walls above. The 1” isolation gap is not required on framed walls located adjacent to foundation walls.
The minimum clearance requirement in all habitable rooms is 7 feet. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable rooms. Habitable rooms should have a minimum floor area of 70 square feet. If a room has a sloped ceiling, the required ceiling height (7 feet) shall be maintained in at least 35 square feet. Beams, HVAC ducts, and plumbing piping shall maintain a minimum height of 6 feet, 6 inches.
Talk to your local building inspector if there is a problem maintaining ceiling heights. There are some exceptions that you may be eligible for.
Gypsum Wallboard (data shown is for 1/2” wallboard with studs at 24” o.c.) – Gypsum wallboard may be installed with the long side either horizontal or perpendicular to the framing. Adhesive is not required.
Cement, fiber-cement, or glass mat gypsum backer board shall be used as backers for wall tile in tub and shower areas and wall panels in shower areas.
|Application of 1/2" gypsum wallboard (w/o adhesive)|
|Location||Max Nail Spacing||Max Screw Spacing||Comments|
|Walls||8" o.c.||12" o.c.||Screws shall be type W or type S and penetrate not less than 5/8” into the wood stud. Nails shall be 1 5/8” gypsum board nails, 0.086” dia., or 1 1/4” ring shank .086” dia.|
|Ceilings||7" o.c.||12" o.c.|
Stairway accidents are the leading cause of home injuries. To minimize falls on stairways complying with the basic code requirements for stair construction is essential.
The stairway rise and run requirements for stairways has changed over the years. Many stairs of older homes were constructed with a treads and risers that do not meet current codes. Newer homes are constructed to a 7-3/4 riser and 10 inch run standard. The basic rise and run do not have to be upgraded to meet current code requirements as part of the basement finish for older homes unless the stairway is being altered. Floor covering materials should be carefully considered because the maximum variation from between the highest and lowest riser is 3/8 inch. Adding a finish material more than 3/8 inch in thickness to the floor in front of the stairs might reduce the height of the first riser too much, and create a code violation.
Open risers are not permitted. As part of the basement finish any existing open risers shall be modified so that a 4 inch sphere could not be passed through. The stairs are required to be constructed so that there is a ¾-inch nosing for each tread.
All stairways shall have a minimum clear width of 36 inches at all points above the handrail height, and below the required headroom height (6’ – 8” measured vertically from the sloped plane adjoining the tread nosings, and floor surfaces of landings and platforms). The minimum clear width of the stairway at or below the handrails is 31.5 inches.
A handrail shall be provided on at least one side of each stairway that consists of 4 or more risers between landings. Handrails shall be continuous along each flight of stairs (from landing to landing) from the top riser to the bottom riser. Handrails shall be placed between 34 and 38 inches above the nosing of steps and provide a graspable surface. The handrail shall have a circular cross-section with an outside diameter between 1-1/4 and 2 inches with a circumference of between 4 and 6 inches. The space between the handrail and wall shall be not less than 1-1/2 inches.
Where the height of any riser on the open side of a stair or landing is more than 30 inches above the floor guardrails are required to prevent falling off of the stairs. Guard rails shall be not less than 34 inches in height measured at the nosing of treads. The guardrail shall have intermediate railings below the guardrail spaced so a sphere greater than 4 inches in diameter cannot pass through at any point, except that a 6 inch limitation is permitted at the triangular opening formed by the intersection of the tread and riser at the bottom of the guardrail.
The Stairway Manufacturers’ Association publishes an excellent aid to understanding the code requirements and terminology relating to stair construction.
Enclosed usable space under stairways
Enclosed accessible space under stairs shall have walls, under-stair surfaces and any soffits protected on the enclosed side with 1/2 inch gypsum board.
Emergency escape and egress openings - 2006 IRC R310
Basements, and all sleeping rooms are required by code to have at least one emergency escape opening with a net clear area of 5.7 sq. ft. A separate egress opening for the adjoining area of the basement is not required if there is an egress opening in a basement bedroom. The minimum net clear opening may be reduced to 5 square feet if your emergency egress opening is a window with the sill not more than 44 inches below the finished grade level adjacent to the window. Emergency escape windows are allowed to be installed under decks, provided the location of the deck allows the window to be fully opened, and provides a path not less than 36 inches in height to a yard area.
Note: On existing homes built prior to January 1, 2001, Overland Park does not require the emergency escape/egress opening unless a bedroom is currently in place or being constructed in the basement. The basement bedroom would be required to have the emergency egress opening. See OPMC16.110.310.1
The emergency escape and egress opening may be a door or window. The opening must open directly to the exterior. Your local window supplier will be able to verify if the window you selected meet the egress requirements.
Emergency escape window wells shall provide a minimum area in front of the window of 9 square feet, with a minimum dimension of 3 feet. Window wells must allow emergency escape windows to fully open. Wells more than 44 inches deep shall be provided with a permanently affixed ladder, usable with the window in the fully open position. The ladder may encroach a maximum of 6 inches into the required dimensions of the window well.
Ladders shall have an inside width of at least 12 inches, shall project at least 3 inches from the wall, and ladder rungs shall be spaced not more that 18 inches on center vertically for the full height of the window well if a cover is provided over the well it shall be open-able from the egress side and provide the same clear areas as required for the window.
Emergency escape windows shall be operational from the inside of the room without the use of keys, tools, or special knowledge. The opening shall have a minimum height of 24 inches and minimum width of 20 inches with the bottom of the open-able portion being not more than 44 inches above the floor
Where casement windows are used, the clear opening width shall be measured with the window in the open position.
Where double hung windows are used, the required clear open-able area shall be provided without using a removable or tilt out sash.
Note: Where windows are adjacent to engineered swales that require minimum low opening elevations, a continuous concrete window well, extending from the footing level to required minimum elevation, is required.
Insulation - approximately 20% of the dwelling heat loss occurs through un-insulated basement walls. Leaving these walls un-insulated can result in condensation occurring on these cool basement wall surfaces. Basement wall insulation is an essential consideration to save energy, keep basement walls warm and reduce the potential for moisture problems. Additional information on this topic can be found in books, magazines or on internet web sites such as: http://www.buildingscience.com/resources/foundations/Understanding_Foundations.pdf
Exterior walls adjacent to finished space shall be insulated. Insulating basement walls is inexpensive and provides a
significant reduction in energy usage. When insulating the walls, do not forget to insulate the exposed rim joist at the top of the walls.
A vapor retarder or barrier is not recommended on the warm side of concrete walls between the insulation and the basement space because moisture that migrates through the concrete wall may be trapped within the wall. This may lead to mold and other moisture related problems in the wall cavity. Moisture that may accumulate with cavities adjacent to foundations should be allowed to dry to the interior through the gypsum board. Foam board is thought by some to be a preferred insulating material for basement concrete walls. Foam board should be applied directly to the concrete wall, and should be covered by ½ inch gypsum board. A more detailed discussion of this issue can be found at the website listed above.
Wood framed walls (including the joist cavity at the rim joist) shall be insulated to provide a minimum R-13 insulation.
Moisture vapor retarders – The vapor retarder helps control air infiltration, and keeps moisture on the warm side (interior side) of the wall where it can be effectively controlled.
Note: Some vapor retarders such as kraft faced paper, are highly flammable. The building code does not allow these flammable vapor retarders to be left exposed. A wall covering material must be applied to separate these products from the usable space. The recommended covering material is ½” gypsum board. Note: Vapor retarders are not required in Overland Park.
Windows – Windows contribute significantly to energy efficiency. New windows shall have an energy efficiency (U-value) of U = 0.4 or less (minimum double glazed window). Single pane windows with storms are not permitted.
If new doors or windows are installed it is extremely important to install them so they are effectively flashed and sealed to keep water from penetrating the structure. Read and follow the window installation instructions. Caulk liberally under the nailing fin so the caulk oozes out around the edges of the fin. Exterior flashing is required above exterior trim piece above the window. The flashing must extend under the siding and over trim piece (Note: Panel siding may require notching so the flashing can be applied).
Air infiltration – Controlling air infiltration significantly increases overall comfort, reduces energy usage, and minimizes moisture migration that contributes to mold growth, and other detrimental effects. Holes for water spigots, air conditioner lines, electrical conductors, cable TV, and exhaust ducts should be sealed with foams or caulks that are made for protection of penetration that are exposed to weather. Doors and windows should be sealed between the frame and the rough opening with approved insulation or foam. Weather stripping should be applied around door openings.