shaftwall and plumbing duct fireproofing
What Is a Shaftwall System?
A shaftwall system is a non-load-bearing, fire-rated wall built from one accessible side. It encloses elevator shafts, stairwells, plumbing risers and mechanical ducts using steel framing, fire-resistant core boards and specified face linings.
Unlike a conventional partition, the installer does not need to enter the shaft. That single-sided constructibility is why shaftwall systems are widely used for commercial high-rise fire walls in Perth and across Western Australia.
A typical shaftwall assembly includes:
- Bottom J-track fixed to the slab.
- Head deflection track fixed to the soffit or structural support.
- 25 mm heavy-duty fire-resistant core board.
- CH-studs that retain the core board by friction fit.
- One or more fire-rated plasterboard layers installed on the accessible side.
- Approved sealants, penetrations and perimeter details.
For CeilingPro projects, the important distinction is simple: a shaftwall is not a collection of “fire-rated-looking” materials. It is a complete tested wall assembly. Replacing a board thickness, stud gauge, fastener spacing or head detail can invalidate the intended fire performance.
How Does Single-Sided Construction Work?
Single-sided construction works by placing the 25 mm core board into the lower J-track, lifting it into the head track and then locking the board edge into a CH-stud. The next board is inserted in sequence, allowing the wall to grow from outside the shaft.
The process avoids scaffolding, suspended access or labour inside a lift well or narrow plumbing riser. It also reduces the exposure of installers to open shafts during the structure’s early construction stages.
3D installation sequence
Accessible floor side Inaccessible shaft side
[Face plasterboard] [CH-stud] ║ 25 mm core board ║ [Open shaft]
└── grips board edge ──┘
1. Fix bottom J-track to slab.
2. Install first 25 mm core board into J-track.
3. Raise board into the deflection head track.
4. Slide CH-stud over the exposed board edge.
5. Insert next core board and repeat at set centres.
6. Fix specified fire-rated face layers from accessible side.The CH-stud’s shaped flanges create a continuous friction-fit pocket around the shaftliner edge. This is not merely a positioning aid; it helps hold the core-board plane while the accessible-side lining completes the tested fire wall.
In practical Perth construction, sequencing matters more than many specifications acknowledge. The shaft must be surveyed before the first board goes up. A slab-edge offset, out-of-plumb concrete wall or misplaced embed can become impossible to correct once several storeys of liner are locked behind the CH-studs.
Which Components Form a Compliant CH-Stud Wall?
A compliant CH-stud wall uses the exact boards, framing, tracks, fasteners, centres, sealants and movement details listed in its tested system. CH-studs are available in different widths and base-metal thicknesses, so they cannot be selected solely by visual similarity.
Common Australian shaftwall components include 64 mm or 102 mm CH-studs, generally supplied in multiple base-metal thicknesses such as 0.55 mm, 0.80 mm and 0.90 mm. The selected profile must suit the tested system, design height, lateral loads and fixing conditions.
| Component | Function | Site-control point |
|---|---|---|
| 25 mm fire-resistant core board | Creates the concealed fire-resisting core | Keep edges intact; reject crushed corners and wet boards |
| CH-stud | Retains adjoining core-board edges | Confirm width, BMT and spacing match the approved detail |
| Bottom J-track | Supports the shaftliner at floor level | Fix to sound substrate at nominated centres |
| Deflection head track | Allows slab movement without crushing the wall | Do not hard-pack or bridge the movement allowance |
| Face plasterboard layers | Completes the fire and acoustic assembly | Stagger joints and use prescribed screw spacing |
| Firestop system | Restores performance at penetrations and perimeter | Use a tested penetration detail, not generic sealant |
The most frequent procurement error is mixing compatible-looking products from different manufacturers. A 25 mm board may physically fit a CH-stud, but the wall must still follow an approved Australian system detail and project fire-engineering requirements.
At CeilingPro, we recommend storing core boards flat, dry and off the slab. In Perth’s winter wet season, boards left on exposed levels can absorb edge damage long before installation. Damaged liner edges make the CH-stud engagement inconsistent and create unnecessary rework.
Why Are Lift and Plumbing Shafts Fire-Critical?
Lift and plumbing shafts are vertical pathways that can allow fire, smoke and hot gases to travel between storeys. Their enclosing walls must maintain continuity at floor levels, penetrations, door openings and the head-of-wall junction.
An elevator fire wall is especially demanding because it must coordinate with lift door jambs, guide-rail brackets, services, structural movement and access requirements. A plumbing duct fireproofing wall has different pressures: high penetration density, moisture risk, pipe movement and ongoing maintenance access.
In our commercial fit-out work, the riser wall often fails first at interfaces rather than in the broad wall area. A crew may build a neat shaftwall field, then allow unapproved penetrations above a ceiling, omit a tested firestop collar at a plastic pipe or bridge the deflection gap with rigid services.
For Perth and WA projects, the National Construction Code requirements, project fire strategy, certifier requirements and manufacturer’s tested system must be read together. Fire-resistance level is not a number to copy from another job. The required rating and exact construction detail must be confirmed for the building classification, shaft function, connected storeys and fire-engineered design.
How Should a Shaftwall Be Installed Step by Step?
A shaftwall should be installed in a controlled sequence: verify the approved system, set out tracks, install liner boards and CH-studs, close the accessible face, then inspect all fire-critical interfaces before concealment.
- Review the approved fire-rated wall schedule, construction drawings and penetration matrix.
- Check slab level, soffit level, substrate strength and opening dimensions.
- Set out the wall line and verify CH-stud centres before fixing tracks.
- Fix the bottom J-track and head deflection track using the specified anchors.
- Install the first 25 mm core board and seat it correctly in both tracks.
- Slide the CH-stud onto the board edge without distorting its flanges.
- Continue board-and-stud installation across the wall.
- Install any nominated insulation only where the tested system permits it.
- Fix base and face board layers from the accessible side at specified centres.
- Complete fire taping, perimeter seals and tested penetration firestopping.
- Photograph concealed work before services or ceilings hide it.
A useful field tolerance is to avoid “forcing” boards into tracks. If a 25 mm core board needs heavy hammering to fit, stop and investigate. It may indicate wrong track depth, slab movement, a bowed board or accumulated dimensional error. Forcing the panel can chip gypsum edges and weaken the friction-fit relationship.
What Failures Commonly Compromise Shaftwall Fire Ratings?
The most common failures are substituted materials, incorrect deflection details, unsealed penetrations, damaged core boards, wrong fasteners and face-board joints that do not follow the tested arrangement. A small variation can break continuity in a fire barrier.
In one high-rise scenario, a services contractor drilled a series of oversized holes through a completed plumbing riser wall to accommodate late pipework. The patching crew filled voids with general-purpose foam. The visible finish looked acceptable, but the wall no longer followed any tested penetration detail. The correct response was not cosmetic patching; it was a documented, compatible firestop repair.
Other avoidable failures include:
- Using a lighter CH-stud gauge than the approved design.
- Fixing the head track rigidly where deflection is required.
- Closing walls before guide-rail, door-jamb or service interfaces are coordinated.
- Running pipes hard against shaftliner boards without movement allowance.
- Omitting tape or joint treatment required by the system.
- Allowing face-board joints to align across multiple layers.
- Treating acoustic sealant and fire-rated sealant as interchangeable.
CeilingPro treats firestop verification as a hold point, not a final cleaning item. The best time to inspect a riser is when the contractor can still see every service, board edge and perimeter junction.
When Should Impact and Moisture Resistance Be Upgraded?
Impact-resistant linings should be considered where lift lobbies, service corridors or maintenance areas expose shaftwall face layers to trolley strikes, equipment movement or repeated access. Moisture-resistant components should be selected only when they form part of an approved system for the exposure.
A plumbing riser beside wet areas can face condensation, intermittent leaks and high maintenance traffic. In those locations, a tougher accessible-side lining can reduce lifecycle repairs, but it must not be substituted casually for the nominated fire-rated board.
Perth’s hot summers create a different challenge. Building movement, rapid dry-out and staged commissioning can expose weak head details. A wall that is tightly packed at the soffit may appear sound at handover, then crack after structural deflection or temperature-driven movement. Deflection head tracks need their designed clearance and must remain free to move.
The cost trade-off is usually favourable: spending modestly on the correct board, movement detail and firestop coordination avoids opening completed corridors, ceilings or lift lobbies later. Rework in an occupied high-rise is routinely far more disruptive than getting the system right during framing.
Can Shaftwalls Improve Acoustic Performance Too?
Yes. Shaftwalls can provide useful acoustic separation when the approved assembly includes the right cavity treatment, face layers, resilient details and perimeter sealing. Fire rating and acoustic performance are related but are not automatically the same.
A lift shaft generates airborne sound and structure-borne vibration. A plumbing riser can transmit water noise, valve impact and pipe movement. Adding insulation may improve acoustic performance, but it must be compatible with the fire-tested assembly and must not obstruct the liner installation or required clearances.
For a commercial high-rise in Perth, specify the shaftwall from the building-performance brief rather than adding acoustic products late. The wall’s measured result depends on more than board mass:
- Shaftliner continuity.
- Number and type of face layers.
- Stud geometry and connection stiffness.
- Acoustic insulation where approved.
- Sealed perimeters and penetrations.
- Isolation of pipes, brackets and service supports.
A small unsealed service gap can undermine acoustic results disproportionately. This is why CeilingPro coordinates fire, acoustic and service trades before the face layers are closed.
Where Does CeilingPro Add Value on WA Projects?
CeilingPro adds value by coordinating shaftwall details early, installing approved systems accurately and documenting concealed fire-critical work before it disappears behind ceilings, services and finishes. This reduces costly rectification on complex Perth commercial projects.
The strongest results come from a pre-installation review involving the builder, fire consultant, hydraulic contractor, lift contractor and wall installer. On high-rise sites, the shaftwall is a coordination zone, not just a partition package.
CeilingPro Expert Views
“The CH-stud and 25 mm core board are fast only when the shaft has been properly set out. On difficult levels, we check slab-to-soffit dimensions at several points, not just at the opening centreline. A 10–15 mm variation can change how the deflection head performs or force boards to be trimmed inaccurately. We also insist that late services use nominated penetration systems. Fire performance is usually lost at the last 2% of the work—above ceilings, around pipes and at door interfaces—not in the middle of a perfectly framed wall.” — CeilingPro Project Team
For Western Australia builders, the practical benefit is clearer programme control. Single-sided shaftwall construction allows adjacent floors and fit-out trades to keep moving without waiting for shaft access to become available.
Could These Checks Prevent Expensive Rectification?
Yes. A documented pre-close inspection can prevent most shaftwall rectification because it catches incorrect materials, movement details, penetrations and face-layer arrangements before finishes conceal them.
Use this handover-ready checklist:
- Confirm the system name and fire rating against the approved drawings.
- Check CH-stud type, width, thickness and spacing.
- Confirm 25 mm core board is undamaged and fully seated in tracks.
- Verify head deflection track and movement clearance.
- Check face-board layer count, screw spacing and joint staggering.
- Inspect lift-door, guide-rail and riser-opening details.
- Confirm all services use tested firestop solutions.
- Photograph each wall zone before ceilings and access panels are closed.
- Record repairs, substitutions and approvals in the project quality file.
For a Perth builder, these records also simplify final certification discussions. They show that the installed shaftwall system was managed as a life-safety assembly rather than treated as ordinary plasterboard work.
What Are the Most Asked Shaftwall Questions?
Can a shaftwall be installed entirely from one side?
Yes. Shaftwall systems are designed for one-sided installation, making them suitable for inaccessible lift shafts, stair shafts and service risers. The core board is inserted into tracks and engaged by specialised CH-studs before face layers are installed from the accessible side.
Does a CH-stud wall need 25 mm core board?
The board thickness must match the approved shaftwall system. Many CH-stud systems use 25 mm fire-resistant core board, but installers must follow the nominated manufacturer detail and fire-tested assembly rather than assuming that any 25 mm board is suitable.
Are CH-studs interchangeable with other shaftwall studs?
Not automatically. CH, C-T and I-stud profiles can have different listing, size, gauge and tested-system requirements. Use only the stud profile, dimensions and base-metal thickness specified for the approved wall design.
How are plumbing penetrations firestopped in a shaftwall?
Each penetration requires a tested firestop detail compatible with the pipe type, pipe size, wall system and required fire rating. Do not use generic foam, mortar or sealant unless it is specifically approved for that penetration arrangement.
Is a shaftwall suitable for Perth high-rise projects?
Yes, provided the system is selected and installed to the project’s approved fire, structural, acoustic and movement requirements. Shaftwalls are particularly useful in Perth high-rise lift shafts and plumbing risers because they can be erected from the accessible floor side.
What Should You Do Before Starting Installation?
Confirm the approved shaftwall system before materials arrive, then coordinate shaft dimensions, penetrations, lift interfaces and deflection details with every relevant trade. This is the most effective way to protect programme, compliance and finishing quality.
The practical takeaways are straightforward:
- Use a tested, fully compatible CH-stud shaftwall system.
- Build from one side in the correct liner-board and stud sequence.
- Preserve movement at the head track.
- Never improvise firestopping around pipes, cables or lift components.
- Inspect and record concealed work before the wall is closed.
- Engage an experienced Perth contractor such as CeilingPro where high-rise coordination and fire-critical installation quality are essential.
A shaftwall may occupy a narrow strip of floor area, but it protects some of the building’s most important vertical pathways. Treat it as a coordinated life-safety system from the first track fixing through to final handover.
