RediStair® Builders Corner content library

Summary: RediStair is a patented slab-to-slab cantilever truss stair system designed to provide predictable performance, consistent geometry, and reduced maintenance in multi-story buildings.

Introduction to RediStair

RediStair is a hybrid stair assembly that integrates two precast concrete stringers and a cast-in-place (CIP) intermediate landing. The system behaves as a slab-to-slab cantilever truss, where reinforcement continuity into the slabs provides a continuous load path. This approach eliminates landing support seats, corbels, or welded components.

Core Benefits

RediStair offers:

• predictable gravity and lateral performance,
• improved accommodation of slab elevation variation,
• consistent riser/tread geometry,
• inherent fire resistance,
• minimal long-term maintenance,
• early installation within the slab cycle.

Related Pages

The RediStair System Overview

Structural Behavior of the RediStair Truss System

Fire Resistance

Summary: RediStair is composed of two precast concrete stringers and a CIP intermediate landing that connects the two stringers, creating a slab-to-slab cantilever truss. The system is designed to be installed early in construction and to accommodate slab variation while maintaining code-compliant stair geometry.

System Components

• Lower precast stringer: spans from lower slab to the intermediate landing,
• Upper precast stringer: spans from intermediate landing to upper slab,
• Cast-in-place intermediate landing: ties the two stringers together.

Structural Concept

RediStair uses reinforcement continuity into both slabs and through the intermediate landing, forming a cantilever truss mechanism. This differs from seat-supported stair systems where landings bear on corbels, ledges, or bearing seats.

Construction Integration

The RediStair system is typically installed early in the slab cycle. The intermediate landing is cast after precast stringer placement, allowing field adjustment to accommodate slab elevation variations and maintain riser and tread consistency.

Related Pages

What Is RediStair?

Structural Behavior of the RediStair Truss System

Installation Sequencing

Summary: Traditional steel and simple-span precast stair systems often rely on bearing seats, corbels, or welded/bolted connections that can disengage during building drift and can be sensitive to slab variation. RediStair uses reinforcement continuity and a CIP landing to provide a continuous load path and improved tolerance accommodation.

Common Stair System Limitations

• Seat-supported landings may disengage during drift events,
• Fixed geometry can amplify slab variation into riser/tread inconsistency,
• Steel systems often require fireproofing and ongoing maintenance,
• Welded/bolted connections can be vulnerable under cyclic lateral demands.

RediStair Differences

• Reinforcement continuity into slabs maintains engagement,
• Field-adjustable landing helps maintain consistent geometry,
• All-concrete system reduces fireproofing scope and maintenance,
• Truss behavior improves predictability under combined gravity and lateral loads.

Related Pages

Steel Stair Systems vs. Precast Stair Systems

RediStair vs. Simple-Span Precast Stairs

Life-Safety Engineering

Summary: RediStair is protected by U.S. Patent 7,976,746 B2, covering its slab-to-slab cantilever truss configuration using two precast stringers connected by a cast-in-place intermediate landing and reinforcement continuity into slabs.

Key Patented Concepts

• Slab-to-slab cantilever truss behavior,
• Two precast stringers connected by a CIP intermediate landing,
• Reinforcement continuity and load transfer into both floor slabs,
• Elimination of bearing seats/corbels/welded components as primary support.

Why It Matters

The patented configuration enables predictable structural performance, improved accommodation of slab variation, and reduced maintenance compared to systems that rely on seats or steel components.

Related Pages

Structural Behavior of the RediStair Truss System

Life-Safety Engineering

Summary: RediStair behaves as a cantilever truss between floor slabs. The lower and upper stringers develop into their respective slabs, and the CIP intermediate landing ties the system together, creating a continuous load path for gravity and lateral demands.

Cantilever Truss Action

Unlike seat-supported stair systems, RediStair’s load path is not dependent on bearing seats or corbels. Instead, reinforcement continuity into slabs and the intermediate landing produces a predictable structural mechanism.

Performance Under Gravity Loads

• Gravity loads are transferred through the stringers and landing reinforcement into slabs,
• Eliminates reliance on localized bearing regions for support.

Performance Under Lateral Loads

• Reinforcement continuity maintains engagement during drift,
• Truss action improves stability under cyclic lateral demands.

Related Pages

RediStair in Gravity and Lateral Load Events

Building Performance: Drift and Shear

Summary: RediStair’s structural configuration provides predictable behavior in combined gravity and lateral events. Reinforcement continuity into slabs helps maintain engagement and reduces the risk of connection disengagement seen in seat-supported systems.

Gravity Events

• Primary load transfer occurs through stringer reinforcement into slabs,
• Intermediate landing ties the system and balances forces.

Lateral/Drift Events

• Slab engagement is maintained by reinforcement continuity,
• Reduces reliance on bearing seats that can lose contact during drift,
• Improves predictability under cyclic lateral loading.

Related Pages

Seismic Performance Overview

Building Performance: Drift and Shear

Life-Safety Engineering

Summary: RediStair is designed to remain engaged and stable during building drift. The slab-to-slab truss configuration reduces the risk of disengagement common to seat-supported landings and improves life-safety reliability during seismic events.

Key Seismic Considerations

• Building drift can cause seat-supported stairs to lose support contact,
• RediStair maintains engagement via reinforcement development into slabs,
• Truss action provides predictable deformation compatibility.

Related Pages

Building Performance: Drift and Shear

Life-Safety Engineering

Summary: RediStair is an all-concrete stair system with inherent fire resistance. It eliminates the need for applied fireproofing systems commonly required for steel stair assemblies.

Inherent Fire Resistance

• Concrete provides inherent fire resistance,
• No spray-applied fireproofing or intumescent coatings required,
• Reduces long-term maintenance associated with fireproofing repair.

Related Pages

Owner and Developer Benefits

Architectural and Aesthetic Benefits

Summary: RediStair’s concrete mass and stiffness reduce vibration and footfall noise compared to many steel stair systems, improving occupant comfort and perceived building quality.

Acoustic Advantages

• Reduced vibration and footfall noise,
• Improved comfort in residential, hotel, and multi-family applications,
• Fewer long-term noise complaints compared to lightweight steel assemblies.

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Acoustic Advantage

Vibration and Comfort Considerations

Summary: RediStair provides architectural benefits through consistent geometry and clean concrete finishes. It reduces coordination complexity and supports aesthetic intent without added fireproofing layers.

Architectural Benefits

• Consistent riser/tread geometry supports code compliance and finish alignment,
• Concrete surfaces can be finished to match design intent,
• No fireproofing layer simplifies finish detailing and reduces bulk.

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Architectural Benefits

Architectural Coordination

Architectural Finishes and Detailing

Summary: Steel stair systems are often fast to fabricate but typically require fireproofing and ongoing maintenance, and can be susceptible to vibration and noise. Precast concrete systems provide mass and inherent fire resistance, but many simple-span precast stairs rely on bearing seats that can be sensitive to drift and slab variation.

Steel Stair Systems

• Often require applied fireproofing,
• Can be noisy/vibratory,
• May need corrosion protection and repainting cycles.

Precast Stair Systems

• Inherent fire resistance and reduced vibration,
• Seat-supported connections can be sensitive to slab variation and drift,
• Geometry consistency can be impacted by slab elevation differences.

Related Pages

RediStair vs. Simple-Span Precast Stairs

Acoustic Advantage

Fire Resistance

Summary: Simple-span precast stairs typically rely on bearing seats or corbels at landings. RediStair replaces seat-supported behavior with slab-to-slab truss action and a CIP intermediate landing, improving drift compatibility and tolerance accommodation.

Simple-Span Precast Limitations

• Reliance on bearing seats/corbels for landing support,
• Potential for disengagement during building drift,
• Sensitive to slab elevation variation affecting geometry.

RediStair Advantages

• Reinforcement continuity maintains slab engagement,
• Field-adjustable landing improves geometry consistency,
• Predictable behavior under combined gravity and lateral loads.

Related Pages

Life-Safety Engineering

Building Performance: Drift and Shear

Summary: RediStair supports architectural intent by providing consistent geometry and an all-concrete aesthetic without added fireproofing. The system simplifies finish detailing and coordination across multiple floors.

Key Architectural Benefits

• Consistent riser/tread geometry,
• Clean concrete surfaces and finish flexibility,
• Reduced bulk and complexity vs. fireproofed steel stairs.

Related Pages

Architectural and Aesthetic Benefits

Architectural Finishes and Detailing

Summary: RediStair can be installed early in the slab cycle, reducing late-project congestion and sequencing risk. The system reduces coordination around fireproofing and offers tolerance accommodation that minimizes rework and punchlist issues.

Key Contractor Benefits

• Early installation reduces schedule pressure later,
• Field-adjustable landing reduces rework from slab variation,
• All-concrete system eliminates fireproofing scope,
• Predictable geometry reduces punchlist risk.

Related Pages

Installation Sequencing

Field Tolerance Accommodation

General Contractor (GC) Coordination

Summary: RediStair reduces lifecycle maintenance by eliminating fireproofing and minimizing steel-related corrosion or repainting needs. Improved acoustic performance and geometry consistency reduce long-term occupant complaints and liability risk.

Key Owner/Developer Benefits

• Lower maintenance vs. fireproofed steel systems,
• Improved acoustic comfort and perceived quality,
• Stable egress performance and reduced liability risks,
• Durable concrete construction over building life.

Related Pages

Fire Resistance

Acoustic Performance

Maintenance and Lifecycle Considerations

Summary: RediStair is designed to reduce life-safety risks associated with seat-supported stair disengagement during drift events. Reinforcement continuity into slabs helps maintain engagement, improving reliability of egress routes under extreme loading.

Life-Safety Focus

• Reduces risk of loss-of-support seen with bearing-seat systems,
• Maintains engagement through slab reinforcement development,
• Supports predictable egress function during seismic events.

Related Pages

Seismic Performance Overview

Building Performance: Drift and Shear

Summary: Building drift and shear demands can cause seat-supported stairs to disengage or experience concentrated damage at supports. RediStair’s slab-to-slab engagement and truss behavior are intended to improve drift compatibility and reduce reliance on bearing seats.

Drift Compatibility

• Seat-supported systems may lose contact during drift,
• Reinforcement continuity maintains engagement through drift cycles,
• Truss action distributes forces more predictably.

Related Pages

Life-Safety Engineering

Seismic Performance Overview

Summary: RediStair’s concrete construction provides an acoustic advantage by reducing vibration and footfall noise compared to lighter stair assemblies, improving comfort and reducing complaints.

Key Points

• Concrete mass reduces vibration transmission,
• Improves occupant comfort in multi-family and hospitality,
• Reduces long-term noise-related service issues.

Related Pages

Acoustic Performance

Vibration and Comfort Considerations

Summary: Successful integration of RediStair depends on early architectural coordination of stair core geometry, landing elevations, and finish requirements. The system’s adjustability helps accommodate field conditions while maintaining code-compliant geometry.

Coordination Topics

• Stair core geometry and slab elevations,
• Finish intent and concrete surface requirements,
• Handrail/guard interfaces,
• Coordination with structural and MEP layouts.

Related Pages

Architectural Finishes and Detailing

MEP Coordination Benefits

Summary: RediStair’s configuration can simplify MEP coordination by reducing steel framing complexity and providing predictable geometry and clearances. Early installation supports coordinated routing and reduces late-stage conflicts.

MEP Coordination Advantages

• Predictable geometry and consistent clearances,
• Reduced complexity compared to steel stair framing/fireproofing,
• Early installation improves coordination timing.

Related Pages

Architectural Coordination

Installation Sequencing

Summary: RediStair requires coordination with the structural engineer (and EReOR) to confirm slab blockouts, reinforcement continuity, and detailing for load transfer. Typical late-design coordination effort is modest relative to full redesign.

Key Coordination Items

• Slab blockouts and embed/edge conditions,
• Reinforcement development into slabs,
• Landing reinforcement detailing,
• Review of drift compatibility intent.

Related Pages

Structural Behavior of the RediStair Truss System

Design Standards and Code Considerations

Summary: GC coordination focuses on sequencing, slab cycle integration, delivery/logistics, and field verification. RediStair can reduce late-stage congestion and minimize rework by accommodating slab variation at the intermediate landing.

Coordination Topics

• Install timing within the slab cycle,
• Site access, hoisting, and staging,
• Field verification of elevations and geometry,
• Landing pour coordination and inspections.

Related Pages

Installation Sequencing

Delivery, Handling, and Storage

Field Installation Checklist

Summary: RediStair is typically installed early in the slab cycle. Precast stringers are set first, then the CIP intermediate landing is formed and poured, allowing field adjustment to maintain consistent stair geometry despite slab variations.

Typical Sequence

• Confirm slab blockouts and elevations,
• Set lower and upper precast stringers,
• Form and place reinforcement for intermediate landing,
• Pour CIP landing and verify geometry,
• Proceed with subsequent slab cycles and finishes.

Related Pages

Field Installation Checklist

Post-Install Verification

Summary: RediStair’s cast-in-place intermediate landing provides a mechanism to accommodate slab elevation variations in the field, helping maintain consistent riser and tread geometry and reducing rework.

How Tolerance Accommodation Works

• Landing elevation and geometry can be adjusted during forming,
• Adjustments help compensate for slab-to-slab elevation variation,
• Supports consistent stair geometry without extensive re-fabrication.

Related Pages

Construction Tolerances & Field Adjustments

Post-Install Verification

Summary: QA focuses on ensuring RediStair components are produced to specification and verified prior to delivery. This includes fabrication checks, reinforcement placement verification, and dimensional confirmation.

QA Focus Areas

• Fabrication and dimensional verification,
• Reinforcement placement and cover checks,
• Concrete quality and curing controls,
• Pre-delivery inspection and documentation.

Related Pages

Quality Control (QC) Process

QA/QC Checklists

Summary: QC verifies that installed RediStair elements meet project requirements in the field, including alignment, elevations, and geometry following landing pour and cure.

QC Focus Areas

• Field verification of elevations and alignment,
• Landing pour inspections and reinforcement confirmation,
• Riser/tread geometry checks post-pour,
• Documentation and closeout verification.

Related Pages

QA/QC Checklists

Post-Install Verification

Summary: Checklists support consistent QA/QC execution across fabrication and field installation, helping ensure dimensional accuracy, reinforcement continuity, and compliant geometry.

Checklist Topics

• Pre-delivery inspections,
• Receiving inspection and handling,
• Pre-pour checks for intermediate landing,
• Post-pour geometry verification and documentation.

Related Pages

Quality Assurance (QA) Process

Quality Control (QC) Process

Summary: RediStair design integrates structural performance requirements with code-compliant stair geometry. Coordination includes reinforcement detailing, slab engagement, and adherence to applicable building codes for stairs and egress.

Design and Code Topics

• Code-compliant riser/tread geometry,
• Structural detailing for slab engagement,
• Compatibility with building drift expectations,
• Coordination with handrail/guard requirements.

Related Pages

Seismic Design and Detailing Notes

Architect Spec Guide (Master)

Summary: Seismic detailing focuses on maintaining engagement and predictable behavior during drift and cyclic loading. Reinforcement development and continuity into slabs is central to RediStair’s intended performance.

Detailing Considerations

• Reinforcement development length and anchorage,
• Landing reinforcement continuity,
• Accommodation of drift demands,
• Coordination with EReOR design intent.

Related Pages

Seismic Performance Overview

Building Performance: Drift and Shear

Summary: Fire performance notes emphasize RediStair’s inherent fire resistance due to its concrete construction. Fire rating considerations focus on concrete assemblies rather than applied fireproofing systems.

Key Notes

• Concrete provides inherent fire resistance,
• Reduced reliance on applied fireproofing systems,
• Coordination of assemblies and penetrations per code.

Related Pages

Fire Resistance

Architectural Finishes and Detailing

Summary: Acoustic notes highlight how concrete stair assemblies reduce vibration transmission and improve perceived quality. Design and construction detailing can further improve acoustic outcomes.

Key Notes

• Concrete mass reduces footfall vibration,
• Detailing can reduce flanking transmission,
• Useful for multi-family and hospitality applications.

Related Pages

Acoustic Performance

Acoustic Advantage

Summary: Stair vibration affects comfort and occupant perception. RediStair’s mass and stiffness mitigate vibration, improving user experience compared to lighter stair assemblies.

Key Considerations

• Stair stiffness and mass influence vibration response,
• Concrete construction improves comfort and quietness,
• Reduced long-term complaints and service calls.

Related Pages

Acoustic Advantage

Acoustic Performance

Summary: RediStair supports multiple finish approaches. Early coordination ensures interfaces, tolerances, and surface expectations align with architectural intent.

Finish and Detailing Topics

• Concrete surface finish expectations,
• Edge conditions, reveals, and joints,
• Handrail/guard attachment coordination,
• Patch/repair approach for closeout.

Related Pages

Repairs, Patching, and Finish Prep

Architectural Coordination

Summary: Early stair installation can improve site safety and access by providing durable vertical circulation sooner. Temporary conditions and protection should be coordinated to maintain safety and prevent damage.

Key Topics

• Temporary protection and access planning,
• Fall protection and edge conditions,
• Maintaining clear egress during construction,
• Protection of finishes and edges from damage.

Related Pages

Installation Sequencing

Field Installation Checklist

Summary: Proper delivery, handling, and storage practices reduce risk of damage and ensure dimensional integrity prior to installation. Coordination includes site access, staging, and lifting plans.

Key Practices

• Confirm site access and delivery windows,
• Use appropriate rigging/lift points,
• Stage components to prevent damage and contamination,
• Protect reinforcement and blockout interfaces.

Related Pages

General Contractor (GC) Coordination

Field Installation Checklist

Summary: A field checklist supports consistent installation quality by verifying slab conditions, stringer placement, reinforcement coordination, and landing pour readiness.

Checklist Items

• Verify slab elevations and blockouts,
• Confirm stringer orientation and bearing conditions,
• Confirm reinforcement placement and continuity,
• Check formwork and landing geometry prior to pour,
• Document as-built conditions.

Related Pages

Post-Install Verification

QA/QC Checklists

Summary: Post-install verification confirms elevations, alignment, and geometry after the intermediate landing pour. This step helps ensure code-compliant geometry and supports closeout documentation.

Verification Topics

• Measure riser/tread geometry for compliance,
• Verify landing elevations and slopes,
• Confirm alignment between floors,
• Document deviations and corrective actions if needed.

Related Pages

Field Tolerance Accommodation

Quality Control (QC) Process

Summary: Minor patching and finish preparation can be completed during closeout to meet architectural finish requirements. Planning patch methods and materials helps maintain aesthetics and durability.

Key Topics

• Patch/repair material compatibility,
• Surface prep and cleaning,
• Coordination of finishes and sealers,
• Protecting edges and corners during closeout.

Related Pages

Architectural Finishes and Detailing

Maintenance and Lifecycle Considerations

Summary: RediStair reduces maintenance compared to fireproofed steel stairs. Routine inspection, cleaning, and optional sealing are typical lifecycle considerations.

Lifecycle Notes

• No fireproofing maintenance,
• Reduced corrosion/repainting scope,
• Routine inspection and cleaning,
• Optional concrete sealer application.

Related Pages

Owner and Developer Benefits

Fire Resistance

Summary: Project deliverables typically include coordination drawings, installation notes, QA/QC documentation, and closeout materials supporting review and long-term recordkeeping.

Deliverable Examples

• Coordination drawings and blockout details,
• Installation instructions and checklists,
• QA/QC documentation,
• Closeout and maintenance guidance.

Related Pages

RFIs, Submittals, and Coordination Workflow

QA/QC Checklists

Summary: A consistent workflow for RFIs and submittals helps prevent delays and rework. Early coordination with the structural engineer and GC supports efficient review and integration into the slab cycle.

Workflow Topics

• Submittal package contents,
• RFI routing and response timing,
• Coordination between trades and disciplines,
• Field verification and documentation of changes.

Related Pages

General Contractor (GC) Coordination

Structural Engineer and EReOR Coordination

Summary: Typical details include slab blockouts, reinforcement development, landing reinforcement, and interface conditions. Drawing notes help coordinate installation and inspection requirements.

Typical Detail Topics

• Slab blockout geometry,
• Reinforcement continuity and anchorage,
• Landing reinforcement and pour notes,
• Finish interface and edge conditions.

Related Pages

Design Standards and Code Considerations

Architect Spec Guide (Master)

Summary: The master spec guide provides suggested specification language and coordination notes for integrating RediStair into project documents, including concrete requirements, tolerances, QA/QC, and closeout.

Spec Guide Includes

• Division placement and scope notes,
• Concrete and reinforcement requirements,
• Installation and tolerance language,
• QA/QC and closeout documentation requirements.

Related Pages

Spec Language: Concrete and Reinforcement

Spec Language: Installation and Tolerances

Spec Language: QA/QC and Closeout

Summary: Spec language addresses concrete performance, reinforcement placement, cover, curing, and inspection requirements necessary for RediStair’s structural intent and durability.

Key Spec Topics

• Concrete strength and durability,
• Reinforcement placement, cover, and development,
• Inspection and verification requirements,
• Finish and patch requirements as applicable.

Related Pages

Architect Spec Guide (Master)

Quality Assurance (QA) Process

Summary: Installation and tolerance language covers slab verification, stringer placement, intermediate landing forming/pouring, and acceptable geometry tolerances to support code-compliant stairs.

Key Spec Topics

• Field verification prior to setting stringers,
• Placement tolerances and alignment expectations,
• Intermediate landing pour and geometry checks,
• Documentation and corrective action language.

Related Pages

Field Tolerance Accommodation

Field Installation Checklist

Summary: QA/QC and closeout language defines inspection, documentation, and verification requirements supporting consistent production and installation quality, including post-install geometry verification and maintenance notes.

Key Spec Topics

• QA/QC documentation requirements,
• Inspection checkpoints and hold points,
• Post-install verification requirements,
• Closeout submittals and maintenance guidance.

Related Pages

QA/QC Checklists

Maintenance and Lifecycle Considerations

Summary: FAQs address common questions related to design adoption timing, coordination effort, fire resistance, maintenance, and performance under drift/seismic conditions.

FAQ Topics

• Design-phase adoption and late-stage integration,
• Coordination effort with structural engineer,
• Fire resistance and fireproofing requirements,
• Maintenance expectations and lifecycle considerations.

Related Pages

Structural Engineer and EReOR Coordination

Fire Resistance

Maintenance and Lifecycle Considerations

Summary: Talking points and case study notes help communicate RediStair’s value in real projects, focusing on schedule benefits, geometry consistency, occupant comfort, and reduced maintenance over time.

Key Talking Points

• Early installation reduces schedule risk,
• Improved geometry consistency vs. slab variation,
• Quiet, solid feel improves user experience,
• Reduced maintenance due to all-concrete design.

Related Pages

Contractor Benefits

Owner and Developer Benefits

Summary: Download and resource content includes specifications, details, guidance documents, and supporting materials for design and construction coordination.

Resource Types

• Specifications and spec guide language,
• Typical details and coordination notes,
• QA/QC checklists,
• Installation and verification guidance.

Related Pages

Architect Spec Guide (Master)

Project Documentation Deliverables

Summary: RediStair support includes coordination through design integration, logistics, installation guidance, QA/QC, and closeout documentation. The goal is predictable performance, consistent geometry, and reduced lifecycle maintenance for owners.

Support Scope

• Design and coordination support,
• Logistics and delivery planning,
• Installation guidance and verification,
• QA/QC documentation and closeout support.

Related Pages

General Contractor (GC) Coordination

Project Documentation Deliverables