How to read a Hong Kong floor plan

A Hong Kong floor plan is a scale drawing that shows the layout of a flat as seen from above, measured to the exterior of the enclosing walls. It tells you the dimensions of each room, where the structural walls are, and the location of features such as the bay window and air-conditioning platform. Because the law governing first-hand sales (the Residential Properties (First-hand Sales) Ordinance, Cap. 621) requires precise measurement rules, the plan is your best tool for understanding the flat’s actual size and shape — but it will not tell you the height of the ceilings, the quality of the light at different times of day, or whether the views are worth the price. You must still view the property, and the plan helps you know what to look for.

Scale and dimensions

Every floor plan in a Hong Kong sales brochure must carry a scale, typically 1:50 or 1:100. Use a ruler to check the stated dimensions against the drawn length — if a wall is marked as 3,000 mm and your ruler shows 30 mm, the scale is 1:100. The dimensions are in millimetres; convert to metres by dividing by 1,000. For example, a room labelled 3,500 by 4,200 mm is 3.5 by 4.2 metres.

The area shown on the plan is the saleable area. Under Section 8 of Cap. 621, the saleable area includes the floor area of a balcony, utility platform and verandah, each measured from the exterior of their enclosing walls. It excludes the air-conditioning plant room, bay window, cockloft, flat roof, garden, parking space, roof, stairhood, terrace, and yard — these ten items are not counted in saleable area, but their areas must be listed separately in the brochure and price list. A vendor may not show any other area figure, such as gross floor area, in the schedule.

When you look at the plan, you will see the saleable area of the flat stated (e.g., “Saleable Area: 500 sq ft”). To find the efficiency ratio (實用率), a market term, you would divide the saleable area by the gross floor area. However, because the gross floor area is no longer published in first-hand sales materials, you can only calculate this ratio from the figures you hold — for example, if you have the property’s gross floor area from an old title deed or a second-hand listing, the ratio is saleable area ÷ gross floor area. There is no official definition or typical percentage; it is a private calculation.

Structural walls vs. partitions

On a Hong Kong floor plan, structural walls are drawn with a thick, solid line or a hatched pattern. Non-structural partitions are thin lines. This distinction matters because structural walls carry the building’s load and cannot be removed; partitions can be demolished or moved, subject to building regulations and management approval.

In a typical Hong Kong flat, the external walls of the flat are structural. The internal walls separating the living room from the master bedroom are often non-structural, which is why many owners create open-plan layouts. However, the walls around the kitchen and bathroom are usually structural or contain plumbing and drainage stacks — moving them is expensive and may require a submission to the Buildings Department. Look at the plan: if a wall is thicker than the others, it is structural. If you are considering renovation, identify every thick line before you buy.

Bay window and air-conditioning platform

The bay window is drawn as a recessed panel on the outer wall, often labelled “BW”. It protrudes from the building facade, and its area is excluded from the saleable area (it is one of the ten Schedule 2 items). In many Hong Kong flats built after 2000, the bay window takes up a significant portion of the bedroom wall — sometimes 600 mm deep and nearly the full width of the room — which means you cannot place a full-length bed against that wall. The floor space within the bay window is usable only for seating or storage, not for permanent furniture. Check the plan: a bedroom that looks 8 feet wide on plan may actually have only 6 feet of usable width if the bay window eats into the room.

The air-conditioning platform (often labelled “A/C” or “AC platform”) is a small outdoor ledge, usually located near a bedroom or living room. It is also excluded from saleable area. On the plan, it appears as a small rectangle outside the main wall. It is designed to hold the outdoor unit of a split-system air conditioner; it does not provide usable indoor floor space. Some newer flats include a “utility platform” (covered in the next section) that also holds the A/C unit, but the platform itself is included in the saleable area if it is part of the property.

Which walls can you remove?

You can remove any non-structural partition, but you may need approval from the Incorporated Owners (IO) or the property management. Structural walls cannot be removed unless you obtain a structural engineer’s report and a permit from the Buildings Department — a costly and lengthy process rarely approved for residential flats. The floor plan shows the difference; if you are unsure, ask a structural engineer to mark up the plan. Never cut into a wall based on the plan alone, as pipework or electrical conduits may run inside even a non-structural wall.

Orientation and facing

Most floor plans indicate north with a compass arrow or the letter “N”. Knowing the orientation tells you how much direct sun the flat gets. In Hong Kong’s subtropical climate, a living room facing south or southeast gets strong morning sun and stays bright until midday, but requires good air-conditioning from April to November. A west-facing flat (called “sai ho” in Cantonese) receives intense afternoon heat, leading to higher electricity bills for cooling. North-facing flats are cooler and less humid, but can feel dark in winter. East-facing flats get morning light, which many prefer.

The plan also shows the “facing” of the main windows: if the living room has large windows on the south wall, the estate will list the property as “south-facing”. This matters for light and air circulation. In a high-density estate, your neighbour’s building may block the sun even if the orientation is theoretically good — the plan cannot show that. You need a viewing at different times of day to judge.

Spotting an awkward layout

A good floor plan allows efficient furniture placement and natural flow. Look for these common problems:

• Long corridors. A corridor that is more than 2 metres long and less than 1.2 metres wide wastes space. It cannot be used for furniture and adds to the walking distance from the entrance to the bedrooms. On the plan, measure the corridor’s length and width.
• Unusable corners. If the living room has a recess or a sharp angle (e.g., a 45-degree wall), the corner may be too narrow for a sofa or a dining table. The plan shows the shape; imagine placing a rectangular sofa in it.
• Doors that clash. When two doors open into each other’s path, you cannot open both fully. For example, a bathroom door that opens into the master bedroom door, with only a 10 mm gap on the plan. Check the door swing arcs: if they overlap, the layout is poorly designed.
• Kitchen layout. A galley kitchen with worktops on both sides needs at least 900 mm between them for one person to move. Narrower than that and it feels cramped. The plan shows the exact width.
• Window placement. If the only windows in the living room are small or off-centre, the room may be dark. The plan shows the window dimensions but not the light intensity at different times.

What the plan does not tell you

No floor plan can show:

• Ceiling height. A flat with a 2.5-metre ceiling feels very different from one with 3.0 metres. The height is stated elsewhere in the brochure or on the building’s plans.
• Noise levels. The plan does not show whether the flat is near a main road, a school, or an MTR line. You must view at rush hour.
• Views. The plan shows the direction of the windows, but not what you see — a concrete wall, a park, or another flat’s window. Viewing is essential.
• Condition of the unit. Age of finishes, water leakage, mould, or cracks are not on the plan.
• Airflow. Cross-ventilation depends on the arrangement of windows; a plan with windows on one side only suggests poor natural ventilation.

What to do with this information

Before you view a property, print the floor plan at actual size (use the scale). Mark the structural walls, the bay window, the A/C platform, and the corridors. Identify any room that looks too narrow for a bed or sofa. Take a tape measure to the viewing and verify the dimensions printed on the plan — measure wall to wall, including the thickness of the walls. If the numbers match, the plan is reliable. If they differ significantly, ask the agent for an explanation. Finally, check the SRPA’s website (www.srpa.gov.hk) for the latest guidance on area measurement and brochure requirements; the rules can change, and the figures in this guide are based on the law as at September 2026.