Landed House A&A in Singapore: Reconstruction vs A&A, Attics, Extensions and Approvals

Renovating a landed house in Singapore looks simpler than renovating a condominium unit: there is no management corporation to satisfy and the house is yours from the soil to the roof. The regulatory picture is the opposite. A landed house sits inside a planning envelope set by the Urban Redevelopment Authority (URA), its structure is governed by the Building and Construction Authority (BCA), and in semi-detached and terrace houses it physically shares walls, foundations and sometimes roofs with the neighbours. The moment you extend, add an attic, dig a basement or replace a large part of the structure, all three of those facts come into play.

The single most consequential question is one that owners rarely ask at the start: is this project additions and alterations (A&A), or is it reconstruction? The answer determines which URA route you can use, which guidelines the new design must meet, and how much of the existing house can be kept. URA draws that line with a set of 50% tests, and they are easy to cross by accident once a design develops.

This guide explains the A&A versus reconstruction line, the planning rules for extensions, roofs, attics and basements, the envelope and setback controls, the BCA structural process and the works that are exempt, Good Class Bungalow Areas, how to deal with party walls and neighbours, and a realistic order of play. It reflects the rules as at 9 November 2026. For the wider map of approvals across all building types, start with our master guide to A&A and fit-out approvals.

A&A or reconstruction: URA’s 50% tests

URA lets owners of existing landed houses lodge certain A&A proposals through a plan lodgment route, where a Qualified Person (QP) declares compliance rather than waiting for a full evaluation. To qualify as A&A under that route, the proposal must stay within limits that URA sets out by category. If it does not, URA says the proposal should be lodged as a new erection or reconstruction instead.¹

Three practical consequences follow.

First, the tests are cumulative in practice. A design that adds a modest rear extension, rebuilds the front wall and replaces the first-storey slab can cross the wall test or the structural test even though the GFA increase is small. The QP needs to quantify each test from the approved plans, not from the house as it stands today.

Second, “approved” matters. The tests are measured against the existing and approved GFA, walls and floor area. URA’s lodgment criteria also require that the retained parts of the house have no unauthorised works.¹ An enclosed back yard or a roof-top room built years ago without approval does not count towards the baseline and may have to be regularised or removed first. Our guide to unauthorised works and regularisation explains that process.

Third, A&A does not escape current guidelines. URA has applied envelope control to landed housing since 11 May 2015, and its guidelines state that existing houses approved under the earlier conventional guidelines must comply with the envelope for A&A works. Where an existing building already exceeds the envelope, no further increase in bulk is supported.² What A&A buys you is the right to keep and work around the existing structure, not exemption from today’s height and setback controls.

When lodgment is not available

URA’s lodgment route excludes sites in a Conservation Area, a Good Class Bungalow Area, or a Special Control Area.¹ Those proposals go through a full planning application (or, for conserved houses, conservation permission). The route also excludes plots affected by road or drain widening, plots with State land, proposals that change vehicular access, and plots that are part-lots without their own cadastral boundary.¹ A lodgment authorisation is valid for two years from URA’s acknowledgement letter and can be extended up to two times; after that a fresh lodgment is needed.¹

Planning permission: what needs it and what does not

URA’s exemption list removes a number of small landed-house works from planning permission. Owners should read it as a list of narrow carve-outs, not as a general licence to build.

URA’s exemption list also carries exclusions, notably for national monuments and conservation buildings, and it reminds owners that other authorities’ clearances, caveats and by-laws still apply.⁷ A useful habit is to ask the QP for a written classification of every item in the design, with the exemption or approval route against each one.

Envelope control: height, storeys, attics and roof terraces

Landed houses are controlled by a three-dimensional building envelope, defined by the storey control for the area and the setbacks, rather than by a fixed floor-to-floor height for each storey.

• Height. The maximum building height is 12 m in a two-storey landed housing area and 15.5 m in a three-storey landed housing area. A house may not exceed the two- or three-storey control or the storey height in the Master Plan, whichever is lower. Height is measured from the external platform level; on sloping sites it follows a sloping envelope from the platform levels at the front and rear setback lines.²⁴
• Storey control. Whether your street is a two-storey or three-storey area is set by URA’s Landed Housing Area plans. Outside the designated areas, and where no street block plan applies, URA states that landed houses are subject to a 3-storey height control.⁸
• Protrusions. Only listed items may project beyond the envelope: car porch roofs, roof eaves, ledges, screen walls between adjoining houses, safety railings or parapets, and lift overruns.⁴ Lift overruns and safety barriers on reinforced concrete (RC) flat roofs may extend up to 1 m above the allowable height.²

Attics

URA describes an attic floor as an incidental space underneath a main roof, confined within the permissible envelope.⁵ Until 2021, the attic had to be set back from the front and rear façades behind a 45-degree line measured from the topmost floor slab. URA’s circular DC21-05, effective 5 July 2021, made permanent a 2019 pilot that relaxed this: the attic can now be proposed flexibly within the two-storey or three-storey envelope.³ The same circular confirmed that owners of existing houses carrying out A&A can use the revised guidelines.³

Roof terraces and mezzanines

Accessible roof terraces must sit at least 3 m below the top of the permissible envelope; roofs closer than that must be RC flat roofs that are not accessible except for maintenance.³ The 3 m allowance exists so that a future owner can add a covering within the envelope. Mezzanines may now exceed 50% of a typical floor plate and may have front-façade windows, provided the house stays within the envelope and each level keeps sufficient headroom.³⁴

Basements

Basements are allowed but are constrained at the boundaries. A fully submerged basement on the road side may extend up to the road reserve line where the part under the green buffer is at least 2 m below ground; on other boundaries it may extend to the site boundary where the part under the 2 m planting verge is submerged at least 2 m, there are no technical conflicts and no adverse impact on the adjoining property, and walls abutting a boundary have no openings into the adjoining site.² On sloping sites, any exposed basement must sit within the envelope.⁴ URA also expects a landed house to function as a single dwelling: internal staircases or lifts should serve the upper floors, and an independent basement staircase cannot be the only access to the basement.⁴

Setbacks and plot controls by house type

URA’s prevailing controls (updated 12 June 2026) set the minimum plot sizes, site coverage and setbacks below. The 7.5 m front setback applies to sites fronting category 3 to 5 roads; larger buffers apply on bigger roads.⁶

Source: URA, Prevailing Planning Controls for Landed Housing.⁶ Roof eaves need a 1 m clearance from side and rear boundaries for most house types, and 1.6 m for Good Class Bungalows.⁶

Good Class Bungalow Areas, briefly

URA’s locational criteria list 39 Good Class Bungalow Areas (GCBAs), among them Belmont Park, Holland Park and White House Park.⁸ In a GCBA only bungalow developments are allowed.⁹ The plot, coverage and setback controls in the table above apply, and sunshading devices need a 1.6 m setback rather than 1.0 m.⁶⁷ Some GCBAs overlap with conservation: URA notes that conservation guidelines also apply to landed housing gazetted for conservation, including parts of Chatsworth Park and White House Park.⁸

For an owner planning A&A in a GCBA, the practical difference is procedural. The URA plan lodgment route is not available in a GCBA,¹ so the proposal goes through a full planning application, and the programme should allow for URA’s evaluation time.

BCA: building works, structural plans and the QP

What needs BCA plans

The Building Control Act requires approved plans and, for structural works, a permit before building works start. Carrying out, or permitting or authorising, building works without approved plans or a permit is an offence carrying a fine of up to S$200,000, imprisonment of up to two years, or both, plus up to S$1,000 a day for a continuing contravention and S$2,000 a day if it continues after conviction.¹⁴ Deviating in a material way from approved plans carries a fine of up to S$100,000, two years’ imprisonment, or both.¹⁴ The offence attaches to anyone who “permits or authorises” the works, which includes the owner who tells the contractor to start early.

For landed A&A, typical triggers for structural plans are: new or extended floors, attics and mezzanines; new beams and columns; removing load-bearing walls; new openings in RC walls or slabs beyond the small service openings that are exempt; basements and sunken pools; new roofs on new structure; and foundations for any of these.

Who submits and how long it takes

Only a QP who is a Professional Engineer (PE) in the civil or structural discipline can apply for structural plan approval. Where A&A does not affect the building’s structural stability, BCA accepts PE-endorsed plans with an “Appendix D” certificate; where works materially affect key structural elements, such as strengthening works, an Accredited Checker’s certificate is generally required.¹³ Landed homes benefit from the Fourth Schedule of the Building Control Regulations, which removes the Accredited Checker requirement for building works for detached, semi-detached, terraced or linked houses for residential purposes not exceeding 3 storeys, and for A&A that does not materially affect key structural elements.¹²

BCA processes complete structural plans without an Accredited Checker within 7 working days and a permit for structural works within 7 working days; with an Accredited Checker, 10 working days for a first submission and 14 for later ones.¹³ BCA notes that CORENET X, its joint submission platform, is mandatory for all new projects by 1 October 2026.¹³

A builder carrying out building works whose plans require BCA approval must hold a BCA builder’s licence; a Class 2 General Builder is restricted to projects valued at S$6 million or less.¹⁸ Our guide to verifying contractor licences explains how to check this.

Exempt “insignificant building works” for landed houses

BCA calls works that need no plan submission insignificant building works, and they are exactly the items in the First Schedule of the Building Control Regulations 2003.¹⁰¹¹ The list was expanded for works carried out on or after 1 April 2025, and several items now apply specifically to landed houses.

Source: First Schedule, Building Control Regulations 2003, as in force on 9 November 2026.¹⁰ A “non-load bearing wall” is one that supports no load other than its own weight.¹⁰

Two cautions. “Exempt from BCA” is not “exempt from URA”: a lean-to extension under item 1(ze) adds floor area, so it needs planning permission unless it fits URA’s 20 m² exemption and its other conditions. And BCA itself reminds homeowners that insignificant works must still be carried out safely, with any approvals required by other authorities such as URA, and in compliance with caveats.¹¹ Whether a wall is truly non-load-bearing is a structural judgement; our guide to hacking walls and structural elements explains how a PE tells.

SCDF: the landed-house exemption and its limit

Fire safety works normally need SCDF plan approval. The Fire Safety (Exemption) Order exempts detached, semi-detached and terrace houses from that requirement where each house does not exceed 3 storeys or 3 levels, including basement and attic, and does not share any facility with another building, provided conditions are met.¹⁷ Those conditions, in force since 24 November 2023, are that the owner appoints a QP; the QP designs the fire safety works to the Fire Code, certifies the plans, supervises and inspects the works and certifies completion; and the owner keeps the plans and certificates available for as long as the relevant system or measure is in use.¹⁷

The trap is the word “levels”. A two-storey house with a basement that adds an attic becomes a four-level house and falls outside the Second Schedule exemption, which brings SCDF plan submission into the programme. Settle the number of levels before the design is frozen. Swimming pools in detached, semi-detached and terrace houses, and retaining walls, fencing and boundary walls, are separately exempt.¹⁷ For how SCDF submissions work when they are needed, see SCDF fire safety approvals.

Neighbours: party walls and protecting adjoining property

Semi-detached and terrace houses share party walls: the wall of your house that is, or will be, shared with your neighbour’s house. BCA and URA’s joint good-practice guide for landed estates sets out what owners should do.¹⁶ It is advisory, and the agencies note that they are not obliged to intervene in neighbour disputes, but its recommendations reflect what BCA expects from a properly run job.¹⁶

• Do not hack the existing party wall to create recesses for new walls, columns or beams, and do not let the contractor use it as formwork or support; use an independent system.¹⁶
• New loads need new foundations. The guide says the PE should design new foundations for new loads and strongly discourages transferring additional load onto existing common foundations.¹⁶
• Weather-proof immediately. Where works affect the neighbour’s roof, install secured canvas sheeting and temporary flashings immediately after the party wall is hacked, and permanent flashings over the common wall afterwards, with the neighbour’s written consent.¹⁶
• Finish what the neighbour sees. In a “breakaway” (for example, a semi-detached house redeveloped into a detached house), the old party wall becomes an exposed wall on the neighbour’s side; the guide asks owners to plaster and paint it and treat any exposed roofing promptly. The same applies to new or extended party walls from a rear extension or added height.¹⁶
• Survey first. The guide advises a pre-construction survey of nearby properties, recording existing conditions, with a copy to the neighbours, and an updated topographical and boundary survey by a Registered Surveyor to confirm the boundary.¹⁶
• Excavation needs engineering. For basements and sunken pools, the guide warns that excavation between intermediate terraces or semi-detached houses can move the ground under the remaining party walls. It calls for an Earth Retaining and Stabilising System (ERSS) for excavation deeper than 1.5 m, designed by a PE and submitted to BCA, and an impact assessment by the PE.¹⁶

If works do damage neighbouring property, the guide states that BCA may revoke the permit for the works, the PE and builder must review the method, and the owner should have the builder rectify the damage.¹⁶

Realistic sequencing for a landed A&A

The agency clocks are short. What takes time on a landed A&A is the investigation, design development around the existing structure, neighbour coordination and any resubmission. Allow for that in the contract programme; our guide to variation orders and provisional sums explains how to keep uncertain structural items from turning into disputes later.

Common mistakes on landed A&A

Letting the design drift past the 50% line

Projects often start as A&A and grow. Each added wall replacement or new slab moves the project towards reconstruction, which changes the URA route and the guidelines the design must meet. Ask the QP to re-run the 50% tests at each design stage, not only at the start.¹

Counting storeys but not levels

The SCDF exemption counts storeys or levels, including basement and attic.¹⁷ Many owners know their area is a two-storey area for URA purposes and assume the fire safety position follows; it does not.

Treating BCA-exempt as approved

A lean-to extension, a 50 m² roof-top shelter or a new boundary wall may be BCA-insignificant¹⁰ and still need URA planning permission, or breach a setback. Planning offences under section 12 of the Planning Act carry fines of up to S$200,000 and up to S$10,000 a day for continuing offences after conviction.¹⁵

Starting before the permit

Section 20 of the Building Control Act applies to whoever “permits or authorises” unapproved works.¹⁴ Mobilising the demolition crew before the structural permit is issued is the most common way owners acquire that exposure. If you are unsure which items need approval, the Approval Navigator gives a first pass, and our addition and alteration services page explains how we scope landed jobs. For terms used in this guide, see the glossary.