What is the standard lift shaft size for a residential apartment in Chennai?

For a standard 6–10 person passenger lift, the internal shaft size is typically 1.8 × 2.0 m to 2.0 × 2.2 m depending on the lift configuration and door type. For a compact 2–3 person home lift, a shaft of 1.2 × 1.2 m to 1.5 × 1.5 m is usually sufficient. Exact dimensions depend on the lift capacity, door opening width and drive type — always confirm with your lift supplier before finalising the structural drawings.

What pit depth is required for a lift in a new building?

Pit depth requirements vary by lift type. For most commercial passenger lifts in India, a minimum pit depth of 1.0 to 1.5 m is standard. For home lifts and compact MRL configurations, pits as shallow as 400–600 mm are possible with certain drive types. The pit must be waterproofed and include a sump drain and pit ladder as required by IS 14665.

Can a lift shaft be added to a building that was not designed for one?

Yes, but it is more complex and expensive than planning it from the start. Retrofitting a lift into an existing building requires identifying a suitable structural location, often involving a new external or internal shaft structure. A structural engineer must assess load distribution and foundation requirements. It is always preferable to plan the shaft during the design stage.

Does MRL (machine-room-less) lift technology change the shaft dimensions?

MRL lifts do not require a separate machine room above or beside the shaft, which saves usable floor area. The shaft dimensions themselves are similar to conventional traction lift shafts, but overhead clearance requirements may vary slightly between drive types. The key advantage of MRL is eliminating the machine room — typically 5–8 square metres per floor that would otherwise be unusable.

When should we involve a lift company in the building design process?

Ideally during schematic design, before structural drawings are finalised. Early involvement allows the lift company to confirm shaft size, pit depth, overhead clearance and structural load points — avoiding costly changes during construction. At minimum, the lift company should review structural drawings before the pit foundation is poured.

Planning a Lift Shaft in a New Building

The most common and expensive lift-related mistake in new buildings is planning the shaft too late. When shaft dimensions are locked into structural drawings without lift company input, builders often end up with a shaft that is either too small for the required lift capacity, too large (wasting expensive floor area), or positioned in a way that creates access and maintenance complications. This guide is for builders, architects and developers planning a lift shaft in Chennai.

Why plan the shaft early?

A lift shaft is a structural element — its dimensions affect beam spans, column positions, slab openings and foundation loads. Changes after the structural work is done are expensive and sometimes structurally impossible. Getting a lift company to review the structural drawings before the pit foundation is poured costs nothing and can prevent significant rework. The rule of thumb: involve your lift supplier at the schematic design stage, not after the building frame is up.

Shaft dimensions — what affects the size?

The required internal shaft size depends on four factors:

Lift capacity: A higher-capacity lift (more persons, more load) needs a larger cabin, which means a larger shaft.
Door type and width: Centre-opening doors require less wall space than side-opening doors but need a slightly wider shaft opening. Standard door widths range from 800 mm to 1100 mm for passenger lifts.
Drive type: MRL traction, hydraulic and conventional traction each have slightly different clearance requirements inside the shaft.
Number of sides open: A lift with openings on one side requires less shaft depth than one with through openings (front and rear).

Standard shaft size reference

The following are approximate internal shaft dimensions commonly used in Chennai for new residential and commercial buildings. These are planning references — your lift supplier must confirm exact dimensions for your specific lift selection:

Home lift (2–3 persons): 1.2 × 1.2 m to 1.5 × 1.5 m internal shaft
Residential passenger lift (6 persons): approximately 1.8 × 2.0 m internal shaft
Commercial passenger lift (8–10 persons): approximately 2.0 × 2.2 m to 2.2 × 2.4 m internal shaft
Hospital / stretcher lift: approximately 2.0 × 2.6 m to 2.2 × 2.8 m internal shaft
Goods lift: Varies significantly — confirm based on platform size and load rating

Pit depth

The pit is the portion of the shaft below the lowest landing floor. Its function is to provide clearance for the cabin and counterweight travel beyond the lowest floor, and space for buffers, pit switch and maintenance access. Standard pit depths for new construction in Chennai:

Home lift (MRL compact): 400–600 mm
Residential passenger lift (MRL): 1.0–1.2 m
Commercial passenger lift: 1.2–1.5 m
Goods lift: 1.2–2.0 m depending on load and speed

The pit must be waterproofed — a common shortcut that causes long-term problems in Chennai's monsoon-affected areas. A sump pit and drain are required by IS 14665. The pit walls and floor should be minimum 200 mm thick RCC.

Overhead clearance (headroom)

Overhead clearance is the clear height from the top landing floor slab to the underside of the lift machine room slab or roof of the shaft. This is needed for the cabin to travel past the top floor, counterweight clearance, and for maintenance access to the overhead sheave or motor. Typical minimum overhead requirements:

MRL traction lift: 3.5–4.0 m above the topmost landing floor level
Conventional traction (with machine room): 3.0–3.5 m above topmost landing, plus a separate machine room of 2.2–2.5 m clear height
Home lift (compact MRL): 2.2–2.5 m above topmost landing

Insufficient overhead clearance is the most common shaft design error in new buildings. Never assume a standard floor-to-floor height is sufficient — measure from the finish floor level, accounting for slab thickness and false ceiling if any.

Machine room vs MRL — which to plan for?

Conventional traction lifts need a dedicated machine room, typically located directly above the shaft. This room houses the motor, drive panel and controller. It must have adequate ventilation (temperature below 40°C), lighting and a minimum internal height of 2.2 m. In most modern new construction in Chennai, MRL (machine-room-less) traction is preferred — it eliminates the machine room, saves floor area and reduces building height by approximately one storey equivalent.

Structural load points

The lift structure transmits dynamic loads to the building at specific points — typically at the shaft walls (guide rail brackets) and at the top of the shaft (for overhead sheaves or machine mounting in MRL). These load points must be communicated to the structural engineer during the design phase. A reputable lift company provides a load data sheet for the structural engineer as part of the pre-order process.

Bester Lifts works with architects, builders and structural engineers during the design phase at no cost as part of the project consultation. Learn more about our lift installation services in Chennai.

Planning a lift shaft in a new building