Basement

Check the guidelines relating to basements for commercial developments

Last updated 9 June 2026

A basement storey refers to a storey of a building which may be partially or wholly below the existing ground level. In so far as storey height control is concerned, basement storeys that protrude more than 1.0m above ground level on any side shall be counted as a storey.

Cross-section diagram of a building showing basements and two stories above ground

Basement Setback and Vertical Openings

The physical limit which the basement may be built up to is shown in the table below.

Table 1: Basement Setback

Type of Basement	Setback from Road Reserve Line	Setback from Common Boundary
Basement with protrusion	Up to the road buffer	Up to the building setback
Sunken basement	Up to the road reserve¹ line, provided the portion underneath the green buffer is submerged at least 2m or more below the ground level	Up to the site lot boundary, provided: the portion underneath the 2m peripheral planting verge is submerged at least 2m or more below the ground level; there are no technical requirements (eg sewerage, drainage) and the basement does not cause any adverse impact to the adjoining property; the side of a basement wall abutting any site boundary shall not have any openings into the adjoining site.

Type of Basement

Setback from Road Reserve Line

Setback from Common Boundary

Basement with protrusion

Up to the road buffer

Up to the building setback

Sunken basement

Up to the road reserve¹ line, provided the portion underneath the green buffer is submerged at least 2m or more below the ground level

Up to the site lot boundary, provided:

the portion underneath the 2m peripheral planting verge is submerged at least 2m or more below the ground level;
there are no technical requirements (eg sewerage, drainage) and the basement does not cause any adverse impact to the adjoining property;
the side of a basement wall abutting any site boundary shall not have any openings into the adjoining site.

¹^{Road Reserve}^{: The plot of land to be vested in the State as required under the Street Works Act. It is demarcated by the line of Road Reserve in the Road Line Plan and the site boundary.}

Basements with vertical openings on the side walls may be allowed only if they are required for natural ventilation and to meet the building regulations. The guidelines are as follows:

While the protrusion measured from the level at the site boundary shall not exceed 1.0 m, basements may be exposed up to 2.0 m from the point where the platform level meets the basement wall (i.e. the earth around the basement wall may be cut to slope down to achieve the 2.0 m basement exposure with openings).
The extent of the slope within the green buffer or peripheral planting verge shall have a gradient of 1:2.5.
Vertical cutting of the earth resulting in a trench around the basement is not allowed.
The extent of the vertical openings or the types of cover over the vertical openings shall be subject to the requirements of the other technical departments.
Horizontal openings to the basement are allowed within the setback distance outside the green buffer and peripheral planting verge, subject to provision of effective screening to hide the view to the basement.

Basement Horizontal Openings