This section will detail the installation of ceramic or stone tile on stairways. Both ceramic and stone tile can be installed over stairways constructed of concrete, steel, and wood. The essential element of stair construction is safety.
According to figures compiled by the National Electronic Injury Surveillance System, 998,000 people received hospital treatment for stair related injuries in the U.S. alone. The reason people fall on stairs can be related to factors such as faulty stair design, construction, maintenance, environment, or the way people use the stairs. The following are the most common design defects leading to falls:
Stair treads are too narrow.
Risers are too high or low.
Irregular stair rise and run dimensions.
Inadequate handrails and handrails which can't be grasped.
Slippery tread surface, especially at the nosing.
Confusing tread pattern, making the nosing hard to distinguish from the balance of the tread.
Distracting surroundings such as confusing lighting, mirrors, shadows, and the like.
The following maintenance and environmental issues are also factors in injuries:
- Water, snow, ice, and or debris on the treads.
- Loose, worn, or improperly installed tile.
- Absent or broken handrails.
- Lighting improperly maintained.
The way a stairway is designed and maintained can either reduce or increase the accident potential. The type of tile chosen for the tread is essential and must include the type of environment the stairway will reside. Federal, State, and local building codes govern stairway design. These codes are in place to protect the user and the builder. These codes also govern stair design to aid the disabled in their use of buildings. All of the requirements in the federal, state, and local codes should be followed.
Installing Tile on Stairs
The nosing design is especially important to design safety. In the U.S., the American with Disabilities Act, or ADA, allows a maximum radius in the tread nosing of ½. For the tread tile, a very rough finish with high COF rating would be a good choice for treads especially in stairways in wet areas. Grooving of the tile at the nosing would also be beneficial. Each state and local building authority establishes the minimum requirements for stair design. These requirements normally in the form of codes need to be followed. These requirements will detail the minimum rise and run, the maximum variation of treads and risers, the construction and placement of handrails, and the shape of the handgrip portion of the handrail. In the U.S., the ADA sets forth additional requirements for disabled access. These include; the color-coding of steps, exterior stairway tread marking, slip resistant treads, maximum nosing distance, and a prohibition against open risers. The two stair illustrations will provide you with an idea of what should rest beneath the ceramic or stone tile on a stairway. Figure A shows a concrete stairs; figure B shows steel stairs.
In Figure A, we see ceramic or stone tile installed over a mortar bed bonded to a set of concrete stairs. In this illustration, the concrete stair substrate would be constructed. The dimension of the substrate would meet the requirements and would leave room for the bonded mortar bed and tile. The concrete substrate should have a medium-rough bush-hammered finish. The concrete should be free from cracks, wax, oil, and curing compounds. A Portland cement slurry is used to bond the tread mortar bed and a Portland cement paste is used to bond the riser mortar bed. The riser mortar bed should be 3/8"-3/4" in thickness while the tread mortar bed should be 1-1/4" thick nominally. The tile is installed using a Portland cement paste on a mortar bed that is still workable or dry/latex Portland cement on a cured bed. Other adhesives can be used as a bond coat. Consult with the Manufacturers instructions for the products you wish to use.
Be sure to select the right tile for the environment in which the stairway is constructed.
Be sure to include freeze/thaw concerns for exterior tile-work in areas that are prone to that problem.
Note: When stairways in exterior locations abut vertical walls, the required waterproofing needs to be tied into the wall waterproofing. This should be accomplished for new as well as remodeling construction.
In Figure B, we see a stairway constructed of steel. Note the two different pan designs to hold the mortar bed. On the upper tread, the tile is adhered over the pan while on the lower tread the tile and mortar bed are encased in the pan. Note the reinforcing wire in the mortar bed. 2" X 2" 16/16 wire or its equivalent is required here. The wire must be welded or fastened in some way the steel stairway. It would be best to weld the wire in place furred up from the bottom and the tread on each stair receives the first mortar. The following images demonstrate the steps to take when installing tile on stairs. Ensure that risers and treads are level before applying mortar.
Then the riser receives its mortar bed.
Each tread and riser mortar bed is smoothed before the lower mortar beds are begun.
Each landing received a mortar bed before the lower mortar beds are established.
Note how the ledgers are leveled against the working lines to insure the mortar bed does not exceed its intended dimensions and all beds are consistently in line.
Lastly the stairs receive the tile layer, which is installed over cured mortar beds using the thin set method.
Note how the technician uses a wood straightedge to straighten and level each course of tile to ensure that the tread and riser dimensions are not compromised and that the tiles remain on plane during the process.
Once the tiling is complete, the job is grouted and sealed following the Manufacturers recommendations for the products used.
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