Why concrete stairs fail (and why "looks fine" is not the standard)
Exterior concrete stairs are one of the most-replaced pieces of residential concrete in Houston. The failures are predictable: inadequate footings in clay soil, missing reinforcement, inconsistent riser heights, no isolation joint from the house. A concrete step that sinks an inch in five years is not a craftsmanship problem with the concrete — it is a foundation problem under the step. We pour steps the way we pour foundations: on properly excavated, properly compacted base, with appropriate reinforcement.
Building code on risers and treads
Houston and Texas residential code requirements for exterior stairs follow the International Residential Code (IRC): maximum riser height 7-3/4 inches, minimum riser height 4 inches, minimum tread depth 10 inches. All risers in a flight must be within 3/8 inch of each other — inconsistent riser heights cause trips and falls. We measure the total rise from grade to landing, divide into equal steps, and design treads of appropriate depth.
Footings: deeper than you think
Step footings in Houston should extend at least 12 inches below grade to clear seasonal moisture changes in the upper clay layer — for some sites, deeper. We dig the footings, place rebar tied to the step reinforcement, and pour footings monolithically with the step structure or as a first pour with dowels into the stairs. Skipping the footing — pouring steps directly on the ground — is the single most common reason steps sink.
Reinforcement: rebar in every step
Concrete steps need reinforcement in two planes. Horizontal rebar runs along the length of each tread to prevent transverse cracking. Vertical rebar runs through the riser-to-tread corner to handle the moment forces where treads meet risers. The amount varies with step width — a 4-foot wide flight typically needs #4 rebar at 12 inch centers in both directions.
Isolation from the house
Steps must NOT be poured rigidly against the house foundation. The foundation and the steps move differently with soil and temperature changes, and a rigid bond creates cracking and separation. We install an expansion joint material (typically 1/2 inch closed-cell foam) between the step and the house, then either dowel the steps to the house with sleeved rebar (allowing movement) or leave them as freestanding structures.
Non-slip finishes
Exterior concrete steps in Houston are wet often — humidity, rain, sprinklers. A smooth troweled finish on outdoor steps is a slip hazard. We use either a broom finish (the standard), an aggregate finish (small stones exposed at the surface for grip), or a texture stamp that adds slip-resistance with a decorative pattern. For decorative stairs we add anti-slip additive into the sealer.
Handrails
IRC requires a handrail on stairs with four or more risers (more than 30 inches of total rise). Some Houston municipalities and HOAs require handrails on shorter flights. We do not install handrails ourselves — we coordinate with a metal fabricator we work with regularly and embed the anchors (post bases or sleeves) in the steps during pour. This is cheaper and stronger than surface-mounting handrails after cure.
Replacing existing steps
For full step replacement, we demolish the existing structure including any cracked or settled footings, excavate to firm subgrade, and pour new footings and steps in a single operation. Steps that have only minor settling can sometimes be slab-jacked (lifted with injected polyurethane foam) at much lower cost — we will recommend the right approach at the estimate.
