Landed interior design: what the rules allow, and what they do not

You can do a lot inside a landed house in Singapore, but not everything you can sketch can be built. That is the real issue with landed interior design singapore: people start by choosing finishes and layouts, then find out later that the wall is structural, the rear extension needs approval, or the staircase cannot just shift because the headroom fails.

For landed homes, the useful question is not, “Can an interior designer draw this?” It is, “What works are purely interior, what counts as building works, and what needs the right professionals and approvals before anyone hacks a wall?”

What “landed interior design” usually covers, and where it stops

Most homeowners use one phrase for everything. In practice, there are three different scopes.

• Interior renovation: finishes, carpentry, wardrobes, kitchen cabinets, bathroom refit, painting, lighting, some non-structural partition changes, doors, sanitary fittings.
• A&A (Addition and Alteration): changes to built form or building elements, such as extensions, façade changes, major reconfiguration, stair alterations, new roof elements, widening openings, and other works that usually need professional submission.
• Reconstruction or rebuild: much heavier works, often close to starting over, with full consultant involvement and a very different budget and timeline.

This matters because the team, cost and risk are different. A lot of confusion comes from trying to buy an A&A job as if it were an interior package.

As a rough 2026 budgeting guide, interior-focused renovation for landed homes is often discussed in these ranges:

• Terrace house: about S$120,000 to S$250,000 for a typical interior renovation.
• Semi-detached: about S$180,000 to S$350,000.
• Bungalow: about S$300,000 to S$800,000 and above.

Other market guides show lower starting points for lighter terrace upgrades, around S$80,000 to S$150,000, and broader landed averages from S$100,000 to S$500,000. The spread is wide because “landed renovation” can mean repainting and replacing two bathrooms, or opening up floors, redoing all services and rebuilding the staircase.

Once the work moves into major A&A, budgets commonly rise to around S$300,000 to S$800,000, and more for larger semi-detached or detached homes. Knock-down rebuilds are usually S$1,000,000 and above. Those figures are not fixed rates. Size, structure, specifications, façade works, consultant input and approval path move them.

What you can usually do without turning the job into a major approval exercise

For most landed interior design singapore projects, the simpler works are still the backbone of the job. These are the things homeowners usually mean when they say “renovation”.

1. Finishes and surface replacement

• Repainting walls and ceilings.
• Replacing floor finishes, such as tiles, vinyl, engineered wood or stone.
• Replacing wall tiles.
• Changing skirting, architraves and internal doors.

These are straightforward in concept. The trade-off is hidden condition. Once old tiles are hacked, the screed may be hollow, waterproofing may be poor, and floor levels between rooms may not match. The drawing is the easy part. The floor preparation is usually what decides whether the result looks right.

2. Kitchen and bathroom refits

• New cabinets and worktops.
• New sanitary fittings.
• New shower screens.
• Relocating some points within practical limits.

This is still “interior” work, but wet areas are where shortcuts cost more later. If you move a floor trap, toilet outlet or shower point, the existing slab condition and pipe route matter. In landed houses, especially older ones, nothing should be assumed to be where the old drawings say it is.

3. Carpentry and built-ins

• Wardrobes.
• TV walls.
• Study units.
• Bay window storage.
• Feature ceilings.

Carpentry is often a major budget line in landed homes because there are more rooms and more wall length. Market guides commonly cite S$20,000 to S$50,000 as a key carpentry component, but larger or more bespoke homes can exceed that. Material, internal hardware, door heights, finish type and site measurement accuracy all change the number.

4. Electrical rewiring and lighting replacement

Many landed houses need more than decorative lights. Older homes often require partial or full rewiring, new circuits, updated distribution boards and better planning for air-conditioning, ovens, heaters and data points.

This is one place where design drawings can mislead homeowners. A lighting plan can show many downlights and cove strips. The real question is load, routing, access and future maintenance. In older houses, concealment sometimes means more hacking and reinstatement than expected.

5. Non-structural partition adjustments

Some internal walls can be removed or added if they are non-structural. That “if” is the whole point. A wall that looks thin is not automatically safe to hack. In landed homes, especially older ones with altered histories, the only sensible route is to verify first.

What often needs more than interior design drawings

This is where many landed projects change category. A homeowner starts with “I just want to open up the space,” then the works cross into structure or building form.

Removing or changing structural walls

If the wall carries load, supports a beam, stabilises the stair zone, or ties into the upper floor slab, hacking it is not an interior decision. It becomes a structural one. That usually means professional assessment and the right submission path before works proceed.

The trade-off is simple. Open plan looks bigger, but structure needs support somewhere. If you remove a wall, you may need a beam. If you need a deeper beam, the ceiling line changes. If the ceiling line changes, services and joinery shift.

Changing the staircase

Homeowners often want a nicer stair, a different direction, open risers, or more floor space below. Staircases are not just furniture. Geometry matters: rise, tread, headroom, landing width and how the stair ties into the slab. If you are changing structure or floor opening, this is no longer a cosmetic job.

Open-riser stairs are a common example. They look lighter. The trade-off is not only cost. They can feel less secure for young children, elderly family members, or anyone carrying things up and down daily.

Extending to the rear, side or roof

The moment you add built area, enclose more space, or alter parts of the external envelope, you are outside the normal interior lane. Whether the work is possible depends on the property type, planning controls, existing condition and approval requirements. That is not something to guess from a Pinterest reference.

Changing the façade

Large new openings, different window proportions, screens, external cladding changes, balcony enclosure or prominent roof changes can trigger a different level of review and coordination. The design issue is visible. The compliance issue is usually what decides whether it can proceed.

Major M&E upgrades

M&E means mechanical and electrical services. In a landed house, this can include new air-conditioning systems, water heaters, pumps, data networks, security, gate power, EV charging and smart controls. None of that is unusual. The issue is coordination.

For example, a whole-home smart system may only cost around S$5,000 to S$20,000 in some budgeting guides, but the final number depends on what “smart” means. Basic lighting scenes are one thing. Full integration of gates, CCTV, air-conditioning, curtains, sensors, intercom and remote access is another. The devices are only part of the cost. Cabling routes, access panels, network planning and power segregation matter too.

Rules: who actually governs landed interior design singapore work

For private landed homes, homeowners sometimes ask about HDB rules. HDB rules are for public housing. They are not the main framework for a private landed house.

For landed residential works, the relevant issues usually sit with:

• Planning and development controls, typically associated with URA.
• Building and structural compliance, typically associated with BCA.
• Workplace safety and site practice, which affects how works are carried out on site.

The practical point for a homeowner is this: not every renovation item needs the same submission path, but once the works affect structure, built form, extensions, external envelope or major building elements, you should expect more than an interior layout drawing.

A responsible builder will separate the job into two questions:

1. What do you want to achieve in use, layout and look?
2. What category of work does each item fall into, and what does that trigger?

That is better than pretending the whole project is one lump sum “ID package”. It usually is not.

How to tell if your idea is interior work, A&A, or something heavier

Idea	Usually interior work?	May require bigger approval path?	Why
Replace tiles, paint, lights, wardrobes	Yes	Usually no	Mostly finish and fit-out works
Redo kitchen and bathrooms in same general positions	Usually yes	Sometimes	Wet area and services changes can complicate the job
Hack internal wall to enlarge living room	Sometimes	Often yes if structural	Need to verify whether the wall is load-bearing
Shift staircase	No, not usually	Often yes	Affects slab opening, geometry and structure
Add attic room or roof terrace enclosure	No	Yes	Changes built form and often structure
Extend rear kitchen or side area	No	Yes	Addition to the building footprint or envelope
Change façade with larger openings or external cladding	Not purely	Often yes	External appearance and building elements are affected

This table is only a sorting tool. It does not replace a proper review of your house.

Budget: what the rules change, not just what the finishes cost

People usually ask for a cost per square foot first. That can be useful, but only if the scope is already clear.

For landed work, broad 2026 budgeting guides often cite:

• Interior-focused standard to mid-range: around S$300 to S$450 psf.
• Premium interior: around S$450 to S$700 psf.
• Landed A&A with structural works: around S$250 to S$350 psf, with complex structural works exceeding S$400 psf.
• Structural or highly bespoke renovation: sometimes S$500 to S$1,000 psf and above, depending on scope.

These figures are not interchangeable. A per-square-foot rate for cabinetry and finishes is not the same as one that includes heavy structural intervention. Consultant fees are also often excluded from public budgeting guides, so homeowners comparing numbers should ask what sits outside the build sum.

Rules affect cost in four direct ways.

1. More consultant input

If the work needs architectural or engineering involvement, there are professional fees and coordination time. Public guides for senior-led or luxury landed design often mention design fees from S$15,000 to S$50,000 and above, separate from build cost. That does not mean every project will fall there. It means you should not assume all professional work is included in a basic renovation price.

2. More site investigation

Before heavy hacking, you may need to verify structure, slab levels, drainage runs, roof conditions or prior unauthorised-looking alterations. Investigation saves rework, but it adds early-stage time and cost.

3. More reinstatement and hidden works

A landed house can carry decades of patching, extension, leaks, old circuits and uneven floor buildup. Once you open one area, the adjacent area often needs making good. The approved drawing may show one wall line. Site condition may force three more changes.

4. Longer sequence

The more approvals and coordination are required, the less likely the job can start in a straight line. Design, review, revision, submission, clarification, then site work. Homeowners who want fast completion often need to reduce scope, not pressure the site team.

Common ideas that sound simple, but usually are not

“We only want to make the ground floor more open”

That could mean removing one partition. Or it could mean affecting a structural wall, shifting air-conditioning routes, relocating the kitchen, moving the DB box, adjusting drainage falls and replacing all the flooring because the old and new levels will not align. Same sentence, very different job.

“We want hotel-style bathrooms”

Large-format tiles, wall-hung fittings, concealed cisterns and flush shower trays can be done, but older landed bathrooms may not have the wall thickness, slab allowance or drainage path you expect. The look is possible more often than not. The trade-off is build-up, maintenance access and cost.

“We want a dry kitchen and wet kitchen”

Very common. The issue is not the concept. The issue is where extraction, drainage, gas or electrical load goes, and whether the intended walls are the right walls to change. In terrace houses, side access and rear service planning often shape the final layout more than the mood board does.

“We can save money by keeping the old floor”

Sometimes yes. Sometimes no. If you are changing partitions, redoing services or chasing a flatter, cleaner line across multiple spaces, patching old floor finishes can cost almost as much in labour and look worse. Retention only saves money when the retained item is still sound, still level enough, and still fits the new layout.

What to check before you brief anyone

If you are planning landed renovation for the first time, gather these first.

• Any existing floor plans, old drawings or documents from purchase.
• A clear note of what you want to change room by room.
• Photos of problem areas: leaks, cracks, ponding, low beams, old DB box, roof access, external walls.
• Your rough budget range, not just an ideal number.
• Your timing constraint, such as school move, tenancy end or parents moving in.

Then sort your wish list into three columns:

1. Must have: works needed for function or condition.
2. Good to have: works that improve use.
3. If budget allows: mostly aesthetic upgrades.

This is not a trick to cut scope. It is the only sensible way to keep the project stable once hidden issues show up. In landed houses, they usually do.

Why buildability matters more in landed homes

A condo unit is contained. A landed house is a stack of different trades across multiple floors, often with outdoor elements, service yards, roof edges, boundary conditions and old alterations. That means buildability matters early.

When the same team thinks about drawing and construction together, some problems show up sooner:

• Whether a hacked wall needs temporary support.
• Whether debris can be removed without damaging common access or finished areas.
• Whether new electrical routes clash with stair soffits or beam depths.
• Whether carpentry sizes can actually be brought up the stair.
• Whether bathroom falls work without creating an awkward step.

These are not glamorous topics. They are the difference between a neat drawing and a workable job.

How homeowners get into trouble

• They assume old drawings match current site condition. In older landed homes, they often do not.
• They treat all walls as equal. They are not.
• They combine too many categories of work under one budget. Interior, A&A and structural works do not price the same way.
• They lock finishes before the layout is proven. That is backwards.
• They compare quotations line by line without checking exclusions. Consultant fees, waterproofing scope, rewiring extent and making good can sit outside.

The trade-off with landed renovation is simple: the more certainty you want before site work starts, the more early checking and coordination you need. That costs time. Usually it saves money later.

FAQ

Do I need approval to renovate the inside of a landed house?

For straightforward interior works such as finishes, carpentry, painting and some like-for-like replacements, the path is usually simpler than for extension or structural works. But if your renovation affects structural walls, staircases, major openings, the façade, roof elements or added built area, you should expect a different approval and consultant process. The exact requirement depends on the house and scope.

How much should I budget for landed interior renovation in Singapore?

For 2026, broad market guides place typical interior-focused landed renovation around S$120,000 to S$250,000 for terraces, S$180,000 to S$350,000 for semi-detached houses, and S$300,000 to S$800,000 and above for bungalows. Lighter jobs can fall below those numbers. Major A&A or structural works can push well above them. The biggest cost drivers are floor area, structural scope, material level, carpentry volume, electrical replanning and whether consultant submissions are needed.

Can I remove walls to get an open-plan layout?

Sometimes, yes. But only after checking whether the wall is structural and what else runs through it. If it carries load or stabilises the building, the change is not a simple hacking job. You may need a different structural solution, and that can affect ceiling level, cost and timeline.

Ask YC about your own flat.