Construction Chase: Definition, Uses, and Best Practices in Building Design
In modern construction, integrating mechanical, plumbing, and electrical systems seamlessly into a building’s architecture is a complex task. One of the most effective and code-compliant ways to achieve this is through a construction chase—a structural cavity or framed-out space designed to house essential building services. Whether it’s a high-rise, a single-family home, or a commercial complex, construction chases play a crucial role in making utility systems accessible, concealed, and safe.
This comprehensive guide will explore the definition, applications, design types, materials, building codes, and installation tips for construction chases.
What Is a Construction Chase?
A construction chase is an intentional framed or enclosed cavity built into a structure to contain and conceal mechanical, plumbing, and electrical systems. These chases can run vertically between floors or horizontally across rooms or ceilings.
They serve several critical functions:
- Organizing infrastructure routing
- Providing access for maintenance and inspection
- Maintaining the architectural aesthetics
- Enabling compliance with building codes (fire safety, noise, spacing)
Construction chases are commonly used to house systems such as:
- Plumbing lines (supply and waste)
- Electrical conduit and cabling
- Gas lines
- Fire sprinkler piping
- HVAC ductwork or condensate lines
Why Are Construction Chases Important?
Construction chases are essential to modern building design for several reasons:
✅ Concealment of Services
They allow builders to hide piping, wires, and ducts, giving a clean finish to interior spaces.
✅ System Organization
Multiple mechanical services can be grouped logically and safely.
✅ Accessibility
When designed with access panels, chases make future maintenance or upgrades easier.
✅ Code Compliance
Chases help maintain separation of systems, protect fire-rated assemblies, and support required clearances.
✅ Aesthetic Integration
They prevent surface-mounted pipes or exposed wires, improving both visual appeal and property value.
Where Are Construction Chases Commonly Found?
| Location | Purpose |
|---|---|
| Bathrooms | Conceal plumbing for sinks, toilets, tubs, and vents |
| Kitchens | Enclose supply/drain lines and electrical conduits |
| Utility Rooms | Group HVAC, gas, and water lines in a central location |
| Basements & Attics | Provide routing for vertical stacks and mechanical equipment |
| Multi-story Buildings | Carry services vertically between floors via riser chases |
Types of Construction Chases
🔹 Vertical Chase
Used to run systems between floors. Ideal for apartment complexes, hotels, or multi-level homes.
🔹 Horizontal Chase
Constructed along ceilings, soffits, or under floors. Common for lateral runs of plumbing, gas, or data systems.
🔹 Wall Chase
A thickened or furred-out wall that hides utility systems, typically used in residential bathrooms or kitchens.
🔹 Ceiling Chase
Boxed-in cavity in a dropped ceiling to hide pipes, ductwork, or conduit.
Common Systems Routed Through Construction Chases
| System | Details |
|---|---|
| Plumbing | Water supply, drainage, and vent piping |
| Electrical | Conduit, cabling, data lines, junction boxes |
| HVAC | Refrigerant lines, small ducts, return air chases |
| Gas Lines | Natural gas or propane pipes to appliances or equipment |
| Sprinkler Systems | Pipes to distribute fire suppression across multiple rooms/floors |
Standard Dimensions for Construction Chases
The chase size depends on the number and type of systems inside.
| Chase Contents | Recommended Width/Depth |
|---|---|
| One or two pipes | 6″–8″ |
| Multiple water/waste pipes | 10″–16″ |
| Multi-service (plumbing + HVAC) | 18″–24″ or more |
| Commercial fire-rated shaft | Up to 36″+ depending on system requirements |
Key Materials for Building Construction Chases
| Material | Purpose |
|---|---|
| Wood/metal studs | Framing the cavity around services |
| Drywall (Type X) | Enclosing the chase, especially where fire-rated assemblies are needed |
| Firestop sealants | Maintaining fire integrity at all system penetrations |
| Acoustic insulation | Reducing noise from flowing water or air |
| Access panels | Providing entry points for future maintenance |
| Pipe hangers/brackets | Securing systems inside the chase |
How to Build a Construction Chase: Step-by-Step
Step 1: Plan the Layout
- Identify which services (plumbing, electrical, HVAC) need routing.
- Choose chase locations that minimize bends and maximize direct paths.
- Coordinate with architectural, plumbing, and mechanical drawings.
Step 2: Frame the Chase
- Use 2×4, 2×6, or metal studs to create the cavity.
- Double-stud or staggered-stud walls may be used for larger chases.
Step 3: Install Systems
- Secure pipes, wires, or ducts using code-compliant brackets or hangers.
- Observe spacing and separation requirements for different services.
Step 4: Firestop and Insulate
- Seal all penetrations with UL-listed firestop systems.
- Apply insulation to pipes and inside the chase to minimize noise and heat loss.
Step 5: Enclose the Chase
- Sheath with drywall or another approved surface.
- Install access doors where valves, cleanouts, or junctions are located.
Building Code Considerations
| Code Topic | Typical Requirements |
|---|---|
| Fire Rating | Vertical or multi-unit chases must maintain 1- or 2-hour fire resistance using Type X drywall and firestop |
| System Separation | Electrical, plumbing, and gas must be isolated unless permitted by code |
| Support and Clearance | All systems must be supported and spaced per plumbing or mechanical code |
| Accessibility | Critical components (valves, traps, junctions) must be reachable via panels |
| Ventilation | Some chases may need ventilation if housing gas lines or combustion flues |
Benefits of Using Construction Chases
- 🔧 Simplifies System Installation: Reduces layout complexity for trades.
- 🔍 Easy Maintenance: Panels allow access without wall demolition.
- 🛑 Improved Fire Safety: Fire-rated chases slow the spread of flames.
- 🔇 Quieter Living Spaces: Insulated chases minimize noise from plumbing or HVAC.
- 🧱 Better Building Aesthetics: Conceals unsightly services behind finished walls or ceilings.
Common Mistakes to Avoid
| Mistake | Why It’s a Problem |
|---|---|
| Inadequate Chase Size | May result in crushed pipes, code violations, or lack of access |
| Lack of Firestopping | Breaks fire-rated assemblies and poses safety hazards |
| Skipping Access Panels | Makes future repairs costly and destructive |
| Mixing Incompatible Systems | Violates code and increases fire/electrical hazard |
| Poor Coordination During Planning | Leads to system clashes or rerouting during rough-in |
Construction Chase vs Mechanical Shaft
| Feature | Construction Chase | Mechanical Shaft |
|---|---|---|
| Size | Small to medium (6″–24″ wide) | Large (2–6 feet wide or more) |
| Use | Encloses specific systems (e.g., plumbing) | Full HVAC systems, elevators, or major utilities |
| Accessibility | Limited via panels | May include full doors or access paths |
| Common In | Residential and light commercial buildings | Commercial, industrial, and high-rise buildings |
Conclusion
A construction chase is a vital element in today’s architectural and MEP (Mechanical, Electrical, Plumbing) planning. It enables a clean, code-compliant, and safe way to integrate utility systems into the building structure without compromising on aesthetics or accessibility.
From vertical riser shafts in apartment complexes to wall chases behind bathroom fixtures, these spaces are foundational to modern building performance. By planning thoughtfully, using the right materials, and following code requirements, contractors and designers can ensure that construction chases remain functional, discreet, and durable throughout the life of the building.
FAQs About Construction Chases
Q1: What’s the difference between a construction chase and a wall chase?
A construction chase is a framed-out cavity used to house building systems, while a wall chase is typically a groove cut into masonry or concrete to bury conduit or piping.
Q2: Do construction chases require fire ratings?
Yes, when they pass between floors or fire-rated walls, chases must be built with fire-resistant materials and sealed with approved firestops.
Q3: Can I run different systems (electrical, plumbing, gas) in the same chase?
Only if allowed by local code. Most jurisdictions require separate pathways for systems unless properly shielded and spaced.
Q4: Are construction chases accessible after installation?
They can be, provided access panels are included during construction at key points like shut-off valves or cleanouts.
Q5: How big should a chase be for standard plumbing pipes?
A chase 12″–16″ deep and 18″ wide is usually sufficient for typical drain stacks and supply lines. Larger chases are needed for multi-system enclosures.
Q6: Can I retrofit a chase into an existing building?
Yes. Contractors can build furred-out walls, soffits, or dropped ceilings to create a chase in retrofit scenarios.
Q7: Do I need insulation in a construction chase?
Insulation is highly recommended, especially around plumbing and HVAC lines, for sound control and thermal efficiency.
Q8: What drywall type should I use to enclose a chase?
Use Type X fire-rated drywall when the chase is part of a fire-rated assembly. Otherwise, standard gypsum board may be acceptable.
Properly designed construction chases allow buildings to be safer, quieter, and easier to maintain—making them an essential component of any well-planned structure.
