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Urban Redevelopment Authority (URA)

Additions and Alterations to Landed Housing

Check the guidelines relating to additions and alterations for semi-detached houses.

Last updated 7 June 2026

Proposals shall meet the following criteria to qualify as an Additions & Alterations (A&A) proposal:

  • Proposed additional gross floor area shall not exceed 50% of the approved gross floor area;

  • External walls that are to be removed and replaced with new walls shall not exceed 50% of the approved external walls;

  • Structural changes to the existing landed dwelling house (e.g. replacing or constructing new columns/beams and reconstructing existing floor slabs) shall not exceed 50% of existing building;

  • Changes/replacement of entire roof (with/without resultant increase in height) shall not involve an additional storey;

  • Where an attic is added, the increase in GFA shall be less than 50%.

Proposals that do not comply with the above criteria for Additions & Alterations shall be considered as Reconstruction proposals. Works resulting in the following outcomes shall also be deemed as reconstruction, regardless of whether the works exceed 50% of the existing building GFA:

  • Increase in storey height (including changes/replacement of any part of the roof involving an additional storey)

  • Change in landed dwelling housing form (for example, from semi-detached house to a bungalow).

For existing landed housing approved under previous landed housing guidelines, new Additions and Alterations works shall comply with the permissible building envelope in the Envelope Control guidelines.

Where the existing building already exceeds the permissible building envelope, the new Additions and Alterations shall not further increase the building bulk. URA will assess such applications on the merits of the proposal to ensure that the outcome is not worse off.

Retaining Existing Non-Conforming Structures in Additions and Alterations Proposals

URA may consider allowing landed houses undergoing Additions & Alterations (A&A) works or reconstruction to retain non-conforming structures1, subject to the following requirements:

  • At least 25% of the existing floor plate shall be retained, comprising an integrated wing of existing columns, beams, floor slab and external walls that includes the non-conforming portion of the house;

  • Submission of a Professional Engineer’s (PE) certification to confirm that structures to be retained are structurally sound, can accommodate the new works proposed, and that appropriate construction methods will be used to ensure that they will not be damaged.

  • If the existing front setback is deficient, there shall be a minimum absolute 2.4m setback distance provided from the front boundary line. The setback is measured from the boundary of the external wall/glass of the bay window.

URA shall be notified immediately if any of the non-conforming structures approved to be retained are demolished. The Qualified Person appointed by the owner shall make an amendment application for the new works to comply with prevailing DC guidelines, before any new works are carried out on site.

1 Non-conforming Structures: Structures within the existing house that were approved and built in the past, but do not comply with the prevailing development control guidelines.