shaftwall and plumbing duct fireproofing
What Is a Single-Sided Shaftwall System?
A single-sided shaftwall is a proprietary fire-rated partition assembled entirely from the accessible side of a shaft. It uses 25 mm fire-resistant shaftliner boards held by interlocking CH-studs, with one or more layers of fire-rated plasterboard fixed to the storey side.
For elevator shafts, plumbing ducts and vertical mechanical risers, the inaccessible side is often the shaft interior. Traditional double-sided framing would require installers, scaffolding and materials within that confined space. A shaftwall avoids that requirement.
The basic assembly has four working layers:
- Base, head and end tracks fixed to the structural slab, soffit and wall returns.
- Heavy 25 mm fire-resistant shaftliner placed vertically into the tracks.
- CH-studs twisted into position to lock each shaftliner edge.
- Fire-rated face board, commonly 16 mm fire-rated plasterboard, screw-fixed from the storey side.
The CH-stud’s profile performs the critical job. Its two return channels grip adjacent shaftliner panels, producing a continuous protected core before the face layer is installed.
A correctly selected shaftwall system may achieve an FRL of -/60/60 or -/120/120, subject to the exact tested configuration and project documentation. It is not a loadbearing wall, not a substitute for structural fireproofing, and not automatically suitable as a smoke-exhaust duct.
How Does a CH-Stud Hold 25 mm Shaftliner?
A CH-stud holds shaftliner by mechanically enclosing the long edges of two adjacent 25 mm boards. The installer places the first board into the base and head tracks, twists the CH-stud over its edge, then slides the next board into the opposite channel before repeating the sequence.
3D installation sequence
STOREY SIDE — installer access only
↓
[Fire-rated face board]
│ screws fixed from storey side
│
╔══╧══╗
║ CH ║ ← CH-stud grips board edges
║STUD ║
┌───╨─────╨───┐
│ 25 mm │
│ shaftliner │ ← shaft side, no installer access required
└─────────────┘
│
[Lift shaft / plumbing riser]The important detail is sequence, not force. Shaftliner must seat fully in the bottom track, and the CH-stud must be twisted into the track and pushed down completely. If a stud is only partly seated, the board line can look acceptable yet lose the intended restraint at the base.
In our commercial fit-out work, the most common framing defect is not a wrong board; it is a CH-stud held 5–10 mm above its final seated position because debris, a proud anchor head or an uneven slab has blocked the track. That error can transfer movement into the face layer and produce cracking around the first floor-to-floor cycle.
For Perth projects, CeilingPro checks track lines before liner installation rather than trying to correct a misaligned wall after face boards are installed. This reduces rework at lift-door jambs, riser access panels and narrow corridor interfaces.
| Component | Installation function | Practical site control |
|---|---|---|
| 25 mm shaftliner | Forms the fire-resistant core | Keep edges intact; reject crushed corners and wet or damaged boards |
| CH-stud | Captures liner edges and supports face boards | Confirm full seating in base track before face boarding |
| J-track/end track | Retains liner at base, head and ends | Install anchors at specified spacings and near track ends |
| Fire-rated face board | Completes the tested fire barrier | Use screw-only fixing in fire-rated areas; avoid stud adhesive |
| Fire/acoustic sealant | Maintains perimeter continuity | Apply continuously at gaps, perimeter junctions and approved details |
Why Are Shaftwalls Used in Perth High-Rises?
Shaftwalls allow fire-rated lift and services enclosures to be built safely without internal shaft access. They reduce the need for shaft scaffolding, wet trades and confined-space work, while creating a thinner and lighter alternative to masonry in many commercial applications.
In Perth and wider Western Australia, this matters on apartment towers, hospitals, hotels, education buildings and commercial developments where trades must close walls progressively while lift equipment, hydraulic services and plumbing stacks are coordinated.
A shaftwall can also make programme sequencing more manageable. The framing crew can build from each completed floor slab, while other shaft trades continue under controlled access arrangements. However, faster installation is not permission to improvise.
The system must match the nominated fire test or assessment. A 25 mm shaftliner with one 16 mm fire-rated face layer may be part of a -/60/60 assembly, while a -/120/120 arrangement may need two face layers or a different approved configuration. Board brand, stud depth, steel thickness, fastener type, spacing, wall height, head detail and penetrations all matter.
Perth’s hot summers add a practical logistics issue. Shaftliner and face board should be stored flat, dry and protected from direct weather exposure. Heat does not replace moisture management: a board softened by site moisture, then baked dry, may retain edge damage or deformation that interferes with tight CH-stud engagement.
Which Fire Ratings and Codes Apply in WA?
In Western Australia, the required shaft enclosure fire rating is determined by the building’s approved design, National Construction Code requirements, fire engineering approach and the proprietary system evidence. The installer must build the specified tested system without unapproved substitutions.
The term “fireproof” is commonly used on site, but it is imprecise. A shaftwall is a fire-resisting construction tested to a stated Fire Resistance Level. It must satisfy the relevant criteria for structural adequacy, integrity and insulation where applicable.
For a commercial high-rise in Perth, verify these items before materials reach the floor:
- The approved architectural wall type and fire-resistance schedule.
- The relevant system manufacturer’s tested or assessed assembly.
- The fire-resistance test basis, commonly AS 1530.4 for elements of construction.
- The project’s approved penetration, access-panel and fire-damper details.
- Head-of-wall movement and structural deflection allowances.
- Required acoustic, impact and durability performance beyond fire resistance.
A reliable benchmark is that a system’s rating belongs to the complete assembly, not to an individual sheet labelled “fire-rated.” Replacing a specified 16 mm board with a different Gyprock or plasterboard product, changing from a 0.9 mm to a lighter CH-stud, or omitting a sealant bead can invalidate the intended system outcome.
CeilingPro treats the approved wall-type schedule as the controlling document. Product availability never justifies mixing components from unrelated systems.
How Should a Single-Sided Shaftwall Be Installed?
Install a shaftwall by setting out and anchoring the tracks, placing the first shaftliner, engaging each CH-stud and subsequent liner board in sequence, then completing the specified face-board layers, joints, perimeter sealing and approved openings from the storey side.
A controlled installation sequence is more dependable than rushing liner sheets into a narrow riser wall:
- Confirm slab levels, wall line, shaft opening dimensions and the nominated head-deflection detail.
- Fix base, head and end tracks using the specified anchors, spacing and edge distances.
- Install the first 25 mm shaftliner into the starting/end track.
- Twist a CH-stud over the board edge, engage it in the track and push it fully down.
- Install the next shaftliner board, then repeat stud-and-board sequencing across the wall.
- Stagger shaftliner butt joints between adjacent boards and reinforce butt joints as the tested detail requires.
- Install fire-rated face boards using the specified screw-only pattern.
- Seal all permitted perimeter gaps and complete approved firestopping around penetrations.
The face board should not be fixed through a deflection head track. The wall needs controlled movement at the head; screwing through this detail can bridge the movement zone and turn normal slab deflection into cracking or damage.
Where wall heights exceed board lengths, avoid lining up shaftliner butt joints in one horizontal row. Stagger them into upper and lower wall zones as detailed in the proprietary system. In practice, a single continuous joint line is a weak coordination point: it concentrates handling damage, makes inspection difficult and can conflict with pipe supports or cable tray brackets.
What Details Commonly Cause Shaftwall Failures?
The most frequent shaftwall failures occur at penetrations, wall heads, openings, joints and service clashes—not across the broad field of the wall. Every interruption in a rated lining needs an approved, compatible detail that preserves the complete assembly’s fire performance.
The following issues repeatedly cause costly rectification on Perth commercial projects:
- Unapproved plumbing penetrations: A pipe passing through liner and face board needs the tested firestop detail, which may include a fire collar, wrap, sealant or a combination. Standard gap filler is not a firestop.
- Over-projecting services: Plumbing and electrical services should not protrude beyond the stud face where they interfere with board installation or create local pressure points.
- Incorrect access panels: A general maintenance door does not automatically preserve the shaftwall’s rating. The access panel must be rated and installed within an approved opening detail.
- Missing head clearance: Fire-rated walls must accommodate structural movement where the system requires a deflection head. Packing the head solid with offcuts defeats the detail.
- Board-edge damage: Broken shaftliner edges may not seat properly in a CH-stud. A damaged board often becomes visible later as a bowed stud line or a face-board joint problem.
- Fixing fixtures only to plasterboard: Heavy pipe brackets, riser supports and fixtures need structural support, studs or purpose-installed blocking—not board-only anchors.
A plumbing riser demonstrates why coordination is critical. If a 100 mm uPVC stack is moved after framing and an installer cuts an oversized opening through the shaftliner, the wall is no longer a standard tested assembly. The correct response is to stop, confirm the approved penetration method and restore the enclosure with the specified firestop system.
When Should You Specify 60-Minute or 120-Minute Protection?
Specify 60-minute or 120-minute shaftwall protection only after the building’s approved fire strategy identifies the required FRL for that shaft location and building classification. The selected wall must match the tested configuration, height limits, loading conditions and permitted service details.
A typical proprietary arrangement may use:
| Intended assembly outcome | Typical board configuration | Key installation implication |
|---|---|---|
| -/60/60 | 25 mm shaftliner plus one 16 mm fire-rated face layer | Strict stud spacing, track fixing and perimeter sealing remain essential |
| -/120/120 | 25 mm shaftliner plus two 16 mm fire-rated face layers, or another tested configuration | Layer order, screw lengths, joint staggering and face-board fixing pattern become more demanding |
The extra layer in a two-hour wall is not merely additional material. It changes screw selection, board-joint layout, fixing density and the time required for inspection. On our production planning, the second face layer commonly adds more than board cost because it adds lifting, cutting, fastening, joint coordination and inspection hold points.
Do not assume a thicker wall is automatically a better wall. A wall can be physically thicker yet fail compliance if its components are not part of one tested or assessed system.
Who Should Inspect and Sign Off Shaftwall Work?
The builder, installer, project superintendent and relevant fire-safety or building-certification team should inspect shaftwall work against the approved documentation before access becomes restricted. Specialist trades must also verify their penetrations and firestopping before enclosure is closed.
At CeilingPro, we recommend hold points at four stages:
- After track layout and anchors are installed.
- After shaftliner and CH-stud engagement, before face boards conceal the liner line.
- After the first fire-rated face layer, especially on multi-layer assemblies.
- After penetrations, access panels, dampers and perimeter firestopping are complete.
Photographic records are particularly valuable for lift shafts and plumbing ducts because the critical shaft-side face becomes inaccessible once the wall is complete. Photos should show board markings where applicable, CH-stud spacing, track anchorage, butt-joint reinforcement, head clearances and penetration systems before they disappear behind the final face layer.
CeilingPro Expert Views
“The shaft is where small shortcuts become invisible defects. In our Perth commercial work, the most expensive rectifications are usually caused by an unverified head detail, a last-minute pipe relocation or a face board fixed through a movement track. We set out the wall around the services first, inspect every liner-and-stud run before sheeting, and treat each opening as a fire detail—not a cutting task. A shaftwall performs only as well as its least controlled junction.” — CeilingPro project delivery team
Can Shaftwall Systems Also Improve Acoustic Control?
Yes, a shaftwall can contribute to acoustic separation, but fire rating and acoustic performance are separate requirements. Insulation, board layers, stud profile, junction sealing and service penetrations must be selected for the project’s required acoustic rating rather than assumed from the fire-rated wall alone.
For hotel, apartment and healthcare projects in Perth, lift motors, water hammer and drainage noise can travel through riser walls. Adding suitable cavity insulation may improve acoustic performance in a tested system, but it must not obstruct liner installation, alter required clearances or conflict with firestopping.
A useful field observation is that acoustic complaints often arise from rigid service connections rather than from the shaftwall boards themselves. A pipe clamp fixed directly to structure, an unisolated tray penetration or a poorly sealed access panel can bypass an otherwise well-built wall.
Coordinate acoustic requirements early with hydraulic, electrical and mechanical trades. Retrofitting acoustic upgrades after the shaftwall is closed is slower, more expensive and may create new fire-rating risks.
What Questions Should You Ask Before Installation?
A compliant shaftwall begins with the right questions: what FRL is required, which exact tested system applies, what movement is expected at the head, and how will every service, damper and access opening preserve the enclosure’s performance?
Before starting work in Western Australia, confirm:
- Is the wall type nominated as a specific proprietary shaftwall system?
- Does the selected system allow the required wall height and internal pressure?
- Are CH-stud depth, steel thickness and spacing specified?
- Are 25 mm shaftliners and face boards from the approved system available on site?
- Is there a coordinated penetration register for plumbing, electrical, mechanical and communications services?
- Are fire dampers, access panels and collars compatible with the required FRL?
- Has the head-of-wall deflection detail been confirmed with the structural design?
- Are inspection hold points programmed before the wall becomes inaccessible?
For high-rise construction, this planning discipline prevents a common late-stage problem: discovering that a riser needs an extra access panel after the wall is complete. If access is foreseeable, frame and fire-rate it as part of the original approved detail.
FAQs
How thick is a typical shaftwall system?
A common single-sided shaftwall using a 25 mm shaftliner, 64 mm CH-studs and one 16 mm fire-rated face board is typically under 100 mm overall. The final thickness depends on the selected system, fire rating, stud depth and number of face-board layers.
Can a shaftwall be installed inside an elevator shaft?
It can be installed from the accessible storey side, which means installers normally do not need to enter the lift shaft to build the wall. The shaft side is formed progressively as shaftliner boards are captured by CH-studs.
Can ordinary plasterboard replace a fire-rated face board?
No. The face board must be the exact fire-rated product, thickness and layer arrangement nominated by the tested or assessed wall system. Substituting ordinary plasterboard can compromise the required FRL.
Does every plumbing penetration need firestopping?
Any penetration through a fire-rated shaftwall must use the approved penetration detail appropriate to the service, opening size and required FRL. Depending on the service, this may require fire collars, wraps, sealants or other tested systems.
Can you screw the face board to the head track?
Not where the specified detail uses a deflection head track. Face board should be fixed as the approved system directs so the head connection can accommodate structural movement without damaging the rated wall.
A well-built shaftwall is a controlled fire barrier, not simply a framed wall beside a lift or pipe riser. For Perth and WA high-rise projects, select one tested system, use its complete component set, coordinate every penetration before framing, and inspect the concealed liner work before face boards are installed. CeilingPro delivers shaftwall installations with the practical sequencing, documentation and junction control needed for reliable fire-rated performance.
