Shaft Walls

What shaft walls are

Shaft walls are asymmetric fire-rated partition systems designed for installation from a single accessible face. They are the required specification wherever a fire-rated wall must be constructed against a void that is inaccessible during construction: the inside of a lift shaft, a closed services riser, or an enclosed staircase structure where only the external face can be reached by fixers.

Standard metal stud partitions cannot be built from one side: the stud frame and board layers require access to both faces during construction. Shaft wall systems resolve this through a proprietary assembly where the structural and fire-performance core (coreboard) is inserted from the accessible side into a pre-erected steel track framework, and all subsequent board layers are fixed to the accessible face only. The completed wall achieves its tested EI fire rating without any element of the construction ever requiring access to the shaft or riser interior.

Construction

The shaft wall assembly starts with J-track sections fixed to the structural floor and soffit at the perimeter of the shaft opening, with C-H stud sections bridging between floor and soffit tracks at standard centres. These sections form the skeleton of the wall from the accessible face only.

Coreboard panels (typically 19 mm high-density gypsum) are then inserted vertically into the J-track from the accessible face, sliding into position panel by panel up the full shaft face. The coreboards form the inaccessible face of the completed wall and provide the primary structural stability of the assembly.

Plasterboard finish layers are then screwed to the accessible face of the C-H studs and coreboards, building up the required number of layers to achieve the tested EI rating. British Gypsum Shaftwall, Knauf Shaft Wall and Siniat Shaft Wall systems each specify the board combination and layer count required for each EI rating at each wall height.

Perimeter detailing at the head, base, and junction with any adjacent solid partition requires careful attention to maintain the fire seal at the boundary conditions. Deflection heads where the structural soffit moves under load require slotted track details to accommodate movement without cracking the boards.

Coordination with lift contractors and structural engineers

Shaft wall installation cannot be planned independently of the lift contractor's programme. In a lift shaft, the guide rail brackets for the lift installation fix through or adjacent to the shaft wall framework. The sequencing question is whether the shaft walls are installed before or after the guide rail installation, and how the guide rail bracket penetrations through the completed shaft wall are firestopped to maintain the EI rating.

Common approaches are: to install the shaft wall framework and coreboard around the pre-positioned guide rail brackets before the plasterboard layers are added; to install the shaft wall complete and then cut through for guide rail brackets in a controlled programme with integrated firestopping; or to install the guide rails first and work the shaft wall framework and coreboards around the completed rail positions. The method depends on the lift contractor's programme, the shaft geometry and the structural engineer's requirements for the deflection head condition.

We agree the sequencing and penetration approach at pre-construction with the principal contractor, lift contractor and structural engineer. The firestopping at any guide rail bracket penetration is confirmed as part of the shaft wall programme and documented for the O&M file.

Services risers and staircase enclosures

Services risers (vertical ducts containing M&E pipework, cabling and distribution equipment) also require one-side construction where the riser is closed during installation. The shaft wall specification for a services riser must accommodate the M&E contractor's access requirements: risers typically need regular access for maintenance, which means the shaft wall may include proprietary access panels or hatches rated to the same EI as the surrounding wall.

Staircase enclosures in retrofit work also commonly require one-side construction where the staircase structure is enclosed and the inside face is inaccessible. Shaft wall systems provide the fire-rated enclosure to the required EI rating from the accessible external face, with the same installation sequence as for lift shafts.

Sectors

Shaft walls appear in every sector with multi-storey buildings: offices with passenger lift cores, industrial and warehouse buildings with goods lifts and services risers, healthcare buildings with clinical lift requirements, and education buildings with lift access provision. The specification is driven by the building's fire strategy and the lift contractor's construction programme in every case.

Get in touch

If you are scoping a shaft wall installation, we would be glad to discuss the brief. Send drawings, the structural engineer's riser detail or the lift contractor's programme with the form on this page and we will come back with a clear next step within one working day. For urgent enquiries call 01332 757830 or email enquiries@eastledge.co.uk.