Chase in a Building: Purpose, Types, and Construction Explained
In modern construction, seamless integration of mechanical, electrical, and plumbing systems is critical for both functionality and aesthetics. One architectural and structural feature that plays a key role in this integration is the chase. A chase in a building serves as a concealed passage that houses essential building services like pipes, wiring, ductwork, and communication cables. Though often hidden from view, chases are vital to the internal infrastructure of residential, commercial, and industrial buildings.
This guide covers everything you need to know about chases in buildings—their definition, design, materials, construction techniques, safety considerations, and more.
🏢 What Is a Chase in a Building?
A chase is a designated cavity or built-in shaft within the structure of a building, designed to contain mechanical, electrical, and plumbing (MEP) systems. Chases can be vertical (running between floors) or horizontal (within or above ceilings or below floors), and they are used to route utilities discreetly without exposing them to the building’s interior.
Essentially, a chase is like a hidden tunnel behind walls, ceilings, or floors, providing a protected space for vital systems while keeping the visible surfaces clean and clutter-free.
🧱 Importance of Chases in Construction
Chases allow builders and engineers to:
- Conceal services such as wiring, plumbing, and ductwork
- Organize infrastructure in centralized, accessible paths
- Enhance aesthetics by eliminating exposed cables or pipes
- Improve building safety through isolated service runs and fire-rated assemblies
- Facilitate future maintenance with designated access points
🔍 Common Types of Chases in a Building
| Chase Type | Purpose | Typical Location |
|---|---|---|
| Plumbing Chase | Houses water supply, drain, and vent pipes | Bathrooms, kitchens, utility areas |
| Electrical Chase | Contains conduit, cables, and junction boxes | Walls, ceilings, risers |
| HVAC Chase | Routes ductwork or refrigerant lines | Ceilings, soffits, utility cores |
| Telecom Chase | Hides data, fiber optic, and communication cables | Server rooms, corridors |
| Vertical Chase | Connects multiple floors for riser systems | Utility shafts, wall cavities |
| Horizontal Chase | Routes systems across a floor or ceiling level | Soffits, floors, interstitial spaces |
🛠️ How Is a Chase Constructed in a Building?
1. Planning Phase
- Identify all systems that will run through the chase.
- Coordinate between MEP trades to avoid conflicts.
- Ensure alignment between floors (for vertical chases).
2. Framing the Chase
- Construct with wood or metal studs, depending on fire rating and design.
- Ensure appropriate spacing and support for utility runs.
- Double-stud framing may be used to increase depth.
3. Installing Services
- Place pipes, conduits, ducts, or cables inside the framed chase.
- Follow spacing and clearance codes to prevent interference.
- Firestop penetrations where chases cross rated assemblies.
4. Enclosing and Finishing
- Use drywall, cement board, or other finishes to close the chase.
- Install access panels at valves, cleanouts, or junction points.
- Apply paint or other interior finishes to blend with adjacent walls or ceilings.
🔥 Fire-Rated Chases
In multi-story or commercial buildings, chases often pass through or connect fire-rated assemblies. In such cases:
- Use Type X gypsum board or other fire-rated materials for enclosure.
- Apply firestop collars, putty, and sealants at penetrations.
- Build the chase to comply with the International Building Code (IBC) and NFPA requirements.
Failing to meet fire-rating requirements can compromise compartmentalization and allow fire or smoke to spread between floors or rooms.
📏 Dimensions and Layout Guidelines
- Depth: Varies from 4″ to 18″ depending on contents.
- Width: Adjusted based on number and size of services.
- Vertical alignment: Chases must stack properly across floors to avoid jogs and turns.
- Accessibility: All service points within a chase must be accessible via panels or open ends.
📊 Benefits of a Chase in a Building
| Benefit | Explanation |
|---|---|
| Visual Cleanliness | Hides unsightly pipes, wires, and ducts from view |
| Functional Efficiency | Centralizes systems for efficient routing and future upgrades |
| Code Compliance | Allows easy integration of fire-rated or sound-insulated systems |
| Maintenance Friendly | Access panels enable easy repair or inspection |
| Improved Safety | Isolates plumbing or electrical systems within protected spaces |
🧰 Materials Used in Building Chases
| Component | Material Options |
|---|---|
| Framing | Wood studs, light-gauge steel studs |
| Enclosure | Drywall, cement board, or fire-rated board |
| Insulation | Fiberglass batts, mineral wool (for sound/fire rating) |
| Firestopping | Fire-rated caulk, intumescent collars, putty pads |
| Access Panels | Plastic, metal, or concealed finish-access types |
🏗️ Chase vs Shaft vs Fur Down
| Feature | Chase | Shaft | Fur Down (Soffit) |
|---|---|---|---|
| Purpose | Conceal building services | Large opening for vertical services | Lowered ceiling area for small ducts |
| Size | Medium (4–18″) | Large (elevator shaft, duct riser) | Small (<12″), used for aesthetic drops |
| Load-Bearing? | No | May be load-bearing | No |
| Fire-Rated? | Optional (based on location) | Always fire-rated in multi-floor settings | Usually not required |
| Accessibility | Panels or hidden hatches | Access through mechanical rooms | Limited; may require ceiling removal |
🧯 Safety and Code Considerations
- Chases must not compromise structural integrity of load-bearing walls or floors.
- Follow NEC (National Electrical Code), IPC (International Plumbing Code), and IBC (International Building Code).
- Maintain minimum separation between incompatible systems (e.g., water and electrical).
- Always include firestopping where systems pass through floors or walls.
✅ When Should You Include a Chase in Building Design?
- In multi-story construction, to stack MEP risers vertically.
- In residential builds, to hide plumbing between floors or from bathrooms and kitchens.
- In renovations, when converting surface-mounted systems to concealed ones.
- In commercial buildings, to centralize mechanical services and reduce maintenance complexity.
❓ FAQs: Chase in a Building
1. What is a chase in building construction?
A chase is a concealed space within a wall, floor, or ceiling designed to route utilities like plumbing, electrical, or HVAC systems.
2. Is a chase the same as a shaft?
No. While both are used to house building systems, a shaft is typically larger and fire-rated for vertical systems like elevators or major ductwork. A chase is smaller and used for multiple smaller systems.
3. Does a chase wall need to be fire-rated?
Only if it penetrates or connects to a fire-rated assembly. Fire-rated chases must meet code with appropriate materials and firestop products.
4. Can I build a chase into a load-bearing wall?
It’s not advisable. Chases should be placed in non-load-bearing walls unless specifically engineered.
5. Are access panels required in chases?
Yes. Any point where systems like valves, junction boxes, or cleanouts are placed should have easily accessible panels for maintenance.
6. Can electrical and plumbing share the same chase?
Yes, but with proper separation and compliance with NEC and IPC to avoid hazards.
7. What is the minimum size for a chase?
Depends on the systems inside. A 6″ deep chase is common for electrical; 10″ or more may be required for plumbing or HVAC.
8. Do chases require insulation?
If used in sound-sensitive or temperature-controlled areas, chases should include appropriate insulation.
9. Can chases be used in retrofits?
Yes, though more challenging than in new construction. Retrofit chases may require wall demolition and reconstruction.
10. Who designs and builds chases in a building project?
Chases are typically designed by architects or MEP engineers and built by framers or general contractors, with input from plumbing/electrical subcontractors.
Conclusion:
A chase in a building is more than just a hidden passage—it is a strategic feature that enables modern infrastructure to operate seamlessly behind the scenes. From concealing critical services to supporting safety, accessibility, and aesthetics, chases are a vital part of any well-designed structure. Whether you’re building new or renovating an old space, understanding how and when to incorporate chases will lead to smarter, more efficient construction outcomes.
