What is a shaft wall system?

A shaft wall (or shaft liner) system is a fire-rated plasterboard enclosure built around service risers, lift shafts, stairwells and vertical ducts. It uses 25mm thick shaft liner panels slotted into C-studs within J-track, with face boards on the accessible side. The system can be installed from one side only, which is its key advantage — no access to the shaft interior is needed during construction.

What fire rating do shaft walls need?

Under Approved Document B, service risers and lift shafts in buildings over 18m (approximately 6 storeys) typically need 120-minute fire resistance. In buildings under 18m, 60-minute fire resistance is usually sufficient. Staircase enclosures need 30 or 60 minutes depending on building height and use. Always confirm the specific requirement with building control.

What are C-studs and J-track?

C-studs (also called I-studs) are C-shaped metal sections that hold the shaft liner panels in place. They are positioned at 600mm centres. J-track is a J-shaped metal channel fixed to the floor and soffit that receives the C-studs and liner panels. The liner panel slides into the J-track, then the C-stud is inserted to lock it in place. British Gypsum ShaftWall and Knauf Curveline are common UK systems.

Do shaft walls need inspection panels?

Yes, wherever there are valves, dampers, access points or serviceable equipment within the shaft. Building Regulations and fire risk assessments determine the number and location. Inspection panels must maintain the fire rating of the shaft wall — use fire-rated access panels (e.g. Profab or Howe Green) tested to the same period as the surrounding wall.

Can shaft walls be installed from one side?

Yes, this is the primary advantage of shaft wall systems over traditional block or stud walls. The liner panels slide into the J-track from the corridor side, and C-studs lock them in place. Face boards are then fixed to the C-studs from the accessible side. This means the shaft interior does not need scaffolding or access at each floor level, significantly reducing installation time and cost.

TradeCalculator.co.uk

Shaft Wall Calculator — Liner Panels, C-Studs & J-Track

Calculate shaft wall components including liner panels, C-studs, J-track, face boards and inspection panels for service risers and lift shafts.

Shaft Perimeter

Total perimeter of the shaft enclosure

Wall Height

Floor to soffit height

Fire Rating120 min for buildings over 18m

Include inspection panel(s)

Required where serviceable equipment is within shaft

Number of Inspection Panels

One per access point / floor level

Liner Panel Price (optional)

Per 25mm shaft liner panel

C-Stud Price (optional)

Per C-stud

Board Price (optional)

Per 15mm fire-rated face board

How We Calculate This

This calculator determines the components needed for a shaft wall system based on the shaft perimeter, height and fire rating requirement.

The formula

Liner panels = Shaft perimeter ÷ 600mm panel width

C-studs = Shaft perimeter ÷ Stud spacing + 1

For a 4m perimeter shaft at 2.7m height: liner panels = 4 ÷ 0.6 = 7 (+ waste = 8). C-studs = 4 ÷ 0.6 + 1 = 8. J-track = 2 × 4 = 8m (3 × 3.6m lengths).