This post reviews key requirements for stairways from the International Residential Code (IRC) and The International Building Code (IBC), specifically for interior open stairs. The minimum code requirements for residential stairs include a vertical stair riser (vertical piece) not exceeding 7-3/4-inches in height (IRC R311.7.5.1). The IBC requires footings for basement walls and exterior foundations, as long as they are load-bearing. Professionals should assess soil conditions and determine the proper depth, width, and placement of footings.
A deck has been approved for footings only, but a small cantilever and stair location change make several footings necessary. A minimum of two 4 bars are required for residential footing, with rebar placed in a grid pattern with spacing no more than 18 inches apart. Footings under a slab to support stairs are not necessary in some cases, but may be necessary in extreme circumstances.
In some cases, frost-protected footings may be necessary for the mid stair landing and the bottom of the stringer. The landing requires enough framing strength to support 40 sq.ft., along with diagonal braces or drywall. Underpinning an existing foundation involves excavating short sections, forming the exposed face, and filling the void with concrete using a jack.
The stairway must be at least 36 inches wide, measured above the handrail, and handrails must not project into the stairway more than 4 ½ inches. A stairway must have between 18 and 2 risers in each flight, with less than 2 risers in a flight.
📹 How to Properly Plan Stairs | This Old House
Tommy shows Kevin how to figure out how many risers are needed for stairs going from one section of the house to another.
Do you need a footing for a step?
Freestanding steps can be built on a flat base alongside an existing garden wall, supported by brick-built low walls that form risers. These walls are filled with hardcore and can be centered on concrete footing strips for up to five steps or a concrete pad for a longer flight. Brick risers can be built up from ground level or laid on compacted hardcore before laying the slab. Brick steps parallel to a brick wall should correspond to the bricks in the existing wall, and the risers must be anchored to the wall for security.
To create free-standing steps next to a brick wall, build them with brick and concrete and anchor them to the wall. Logs can be used to support a single step on a gentle slope or arrange them at intervals on a long incline. To anchor the steps safely, “tooth in” the adjoining brick in every third course of the low walls that support them to the brickwork of the existing wall.
Do concrete steps need a footer?
The height of each individual step in a stairwell should be 7 inches, and the width should be 10-12 inches. The stairwell should be 3 1/2 feet wide, preferably wider. Steps with a height of more than 5 feet should have a landing with at least a 3 ft. run. Concrete footings are necessary when concrete steps attach to a building, usually installed by the foundation contractor. If there is no foundation, 8-12 inch diameter sono tubes should be installed at the base of the stairway, extending 4 ft below the frost level. To determine the number of stairs, divide the total rise by the individual rise you plan to use, usually 7 inches, and round off.
Do stairs need foundation?
Stairs snap to structures, requiring a foundation and wall support. Wall tiles can only fit under one-high staircases, not two-high ones. Triangular walls are necessary for two-high staircases, as they must remain visible and not overlap with another structure. Stairs cannot be built downwards due to the need for foundations or walls attached to them. Walls cannot be placed on the bottom side of stairs due to support.
Foundations can only go off the ground, so roof tiles are used for cliffs slightly lower than two staircases. Stairs cannot snap anything to the side, so every staircase must have wall support under it.
Does a staircase need support?
Metal-framed stairways are capable of spanning over 16 feet without the necessity of an intermediate support, whereas wooden stairways require the incorporation of an intermediate support under the risers at 12 feet. Structural stair assemblies with integral support framing are capable of spanning considerable distances when the stringers are constructed in a manner that emulates the principles of truss engineering.
Do stairs need footings?
Stairways require a footing at the bottom to support the stringers, which must be sized to support the load on the stairs, as quantified by the International Residential code. The footings should be 12 inches deep for freestanding decks and 12 inches deep for decks connected to the house via a ledger. The stair footing must be set to the frost depth or deeper for the area, while the deck must be 12 inches deep for freestanding decks.
The IRc does not provide prescriptive designs for footings at stairways, but the Design for code Acceptance (DcA) 6 Prescriptive Residential Wood Deck construction Guide provides a solution, showing 4×4 guardrail posts alongside the stringers.
These posts bear on top of concrete footings placed at either frost depth or the 12-inch minimum depth, whichever is deeper. Jack studs are fastened beneath the bottom of the stringer to transfer the stringer load to the footing.
How far can stairs span without support?
Stair stringers should not exceed 13 feet and 3 inches for closed stringers and 6 feet for cut stringers, as per the American Wood Council’s 2018 Prescriptive Residential Wood Deck Construction Guide. If the span exceeds these dimensions, a support or intermediate landing may be installed. Stairways should be able to hold up a live load, specified as 40 pounds per square foot for residential applications.
Individual stair treads should be designed for a uniformly distributed live load of 40 pounds per square foot, 100 pounds per square foot for other applications, or a 300-pound concentrated load acting over an area of 4 square inches, whichever produces the greater stresses.
The 2021 IRC, R311. 7. 3, states that a flight of stairs should not have a vertical rise greater than 12 feet and 7 inches between floor levels or landings. However, exceptions exist for stairways not within or serving a building, porch, or deck, stairways leading to non-habitable attics, and stairways leading to crawlspaces.
How are interior stairs supported?
In the context of staircase construction, stringers are defined as structural supports, with a range of variants currently in use. They are composed of string fascia, a finished surface on the inner vertical surface, and stringer capping, a top-face finish. The shoe mold serves to bridge the gap between the shoe and the drywall surface of the wall, thereby providing additional support.
How deep should step footings be?
The depth of the footings should be 12 inches, with the width being determined by the number of stories. The depth of the footing should be 12 inches for a single-story building, 15 inches for a two-story building, and 23 inches for a three-story building.
How deep should a footing be for steps?
Ian, a common question about installing footings under steps is that they are a foundation made of concrete and rebar that spreads vertical loads from the steps. They must be installed below the frost depth, which is the maximum depth the ground will freeze in any particular area. In the Twin Cities metro area, frost depth is 3 1/2 feet. Footings prevent the set of steps from settling or moving, ensuring that the steps are poured exactly where they are poured. This is important when steps are attached to any structure built on a footing/foundation.
In case of entry steps, it is important to avoid steps moving relative to the house, as sinking could cause a large step down from the house, pulling away could create a gap between the steps and house, and prematurely causing the steps to degrade. Most code ordinances require footings, but many contractors did not install them to save on costs.
On the other hand, lawn steps do not need footings because they are not attached to anything else with footings. If a set of lawn steps moves due to frost heave or other reasons, the consequences do not justify the cost of installing footings. Overall, LCM recommends installing footings for entry steps and most cities, but some contractors may violate code and install steps without footings.
What are the basic requirements of stairs?
The width of stairs in public and residential buildings should be 1. 8 meters and 0. 9 meters, respectively, with a maximum flight of 12 steps and a minimum of 3 steps, respectively, and a flatter pitch of long stairs through the introduction of a landing.
Can you build a foundation without a footer?
A foundation slab can be poured without footings, known as floating slabs, which are ideal for smaller structures. Monolithic concrete slabs are another option for slab foundations without standalone footings, although the vertical edges of the single-pour slab act as footings. The depth of a foundation footing can range from 2 feet to 8 feet or more, depending on factors like the depth of the frost line. Footings distribute the load of the foundation and structure above to soil that won’t see expansion or upward movement, ensuring the soil underneath doesn’t freeze or fluctuate in moisture content.
Footings for foundations and foundation systems can be poured together, with floating slab foundations and monolithic slab foundations being common examples. Both types lack traditional footings underneath the slab, making them considered footings.
📹 Do All Stairs Need A Concrete Footing Below The First Step or Can It Sit On Concrete Slab?
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I have a question that I’m having trouble finding an answer for, so, since you seem to be t(e stair expert, I’ll ask you. I had a floating deck built, and because of uneven ground grade, it was decided to build stairs. They dug out for a 3 step stair, (in my opinion it should have been 2 treads) but that dig out caused the bottom step to be below grade. So if you walk down the steps, your foot when leaving the bottom step, you have to step up on a gravel ( was drive way) slope. They’ve gone, a phone call to them they suggested bringing in a bobcat or a grader to level down the drive to the level of what should be the bottom of the stair. Can I just pull gravel over the bottom step, which MIGHT save$$$ and solve the problem.