Floor plan symbols are simple shapes, lines and marks that represent parts of a building. They graphically show where walls, doors, windows, stairs and fixtures are located without describing every item in words.
Usually, symbols are easy to recognise, but their look can vary between countries, drawing offices and software. A floor plan legend (key) explains the symbols used on that particular drawing. Check it whenever a mark is unclear.
In this guide we will tell you about common examples and explain how to read them.
Walls, doors and windows
These architectural symbols show the building’s layout and the openings between spaces. You can start by finding the outside walls, then follow the internal walls to identify individual rooms.
Wall and door symbols
| Name | How it is drawn | What it means |
|---|---|---|
| Solid wall | Two parallel edges, often with a solid or patterned fill between them. | A wall shown with its thickness. The fill may identify its material. |
| Partition wall | A narrow band or pair of closely spaced lines. | A wall dividing internal spaces. Its appearance alone does not prove whether it carries structural loads. |
| Single hinged door | A line representing the door panel, with a curved arc from its free end towards the wall opening. | One door panel. The arc shows its opening path and the side on which it swings. |
| Double hinged door | Two door panels in one opening, usually with two swing arcs. | A doorway with two hinged panels. |
| Sliding door | Thin rectangular panels on parallel tracks, sometimes with a movement arrow. | A door that moves sideways rather than swinging into the room. |
| Bifold door | Connected short panels shown at angles, often forming a folded V shape. | A door with panels that fold together as it opens. |
| Door swing arc | A curved line centred on the hinge point. | The path of the door’s outer edge. It helps show where clearance is needed. |
Door arcs are useful when checking a layout. For example, an inward-opening bathroom door may need space beside a basin or toilet. The arc shows the opening path, but it does not show every clearance required around the doorway.
| Name | How it is drawn | What it means |
| Fixed window | Thin parallel lines or a narrow frame inside a wall opening, without an opening arc. | A window that does not open, when confirmed by its label or window schedule. |
| Casement window | A window frame with a hinged panel and, in some drawings, a swing arc. | A window with a sash that opens on hinges. |
| Bay window | Several window sections arranged around a projection beyond the main wall line. | A window area that extends outwards from the room. |
Sweet Home 3D can display opening arcs for suitable door and window models. The exact appearance depends on the selected object.
Stairs, openings and levels
Stair blueprint symbols help you understand how different floors connect. Look at the shape of the staircase, its landings and any direction labels.
| Name | How it is drawn | What it means |
| Straight stair run | A long rectangular outline divided by parallel lines across its width. | A flight of stairs. The lines represent the step layout. |
| Stair direction arrow | A line along the stair run with an arrowhead and an UP or DN label. | The direction of travel upwards or downwards from the floor shown. |
| Spiral staircase | A circular outline with wedge-shaped steps around a central point. | Stairs that turn around a central support. |
| Floor opening | An outlined area in the floor, commonly labelled VOID or OPEN TO BELOW. | A space without a floor at the level being shown. |
| Level change | A boundary or step line with a height note, such as +0.150 m. | A change in floor height relative to the drawing’s reference level. |
A construction plan represents the building at an imaginary horizontal cut. A stair flight crossing that cut may have a diagonal or zigzag break mark. Parts beyond it may use dashed lines. Check the drawing’s convention rather than assuming every stair uses the same break symbol.
Sweet Home 3D displays staircase models in plan view. You add direction arrows with the polyline tool and labels with the text tool. Its model view does not automatically reproduce every construction drawing convention.
A ramp is commonly shown as an outlined sloping area with an arrow and a slope or level note. Sweet Home 3D has no dedicated native ramp-symbol tool.
Read how to customise staircases if you want to learn more about stair height, floor openings and direction arrows.
Kitchen and bathroom floor plan symbols
Fixtures and appliances usually appear as simple outlines seen from above. More detailed plans may include bowls, burners, taps or other identifying features.
| Name | How it is drawn | What it means |
| Kitchen sink | A rectangular outline containing one or two smaller bowls, sometimes with a draining area. | The position and footprint of the kitchen sink. |
| Hob or cooktop | A rectangle containing circles or marked cooking zones. | A cooking surface fitted into a worktop or range. |
| Oven | A rectangular appliance outline, sometimes labelled OVEN. | An oven position. A note may identify whether it sits below a worktop or in a tall unit. |
| Refrigerator | A rectangular outline, often labelled FR, REF or FRIDGE. | Space occupied by a refrigerator. |
| Dishwasher | A rectangle beneath or beside the worktop, often labelled DW. | A dishwasher position. |
| WC or toilet | An oval or rounded bowl connected to a smaller rectangular cistern outline. | The toilet’s position and orientation. |
| Washbasin | An oval or rectangular bowl, sometimes inside a counter outline. | A handwashing basin. |
| Bath or bathtub | A long rectangle with a rounded inner outline. | The bath’s position and footprint. |
| Shower | A square or rectangular tray, sometimes with a drain mark and enclosure lines. | A shower area or enclosure. |
These house plan symbols show location and size, but not necessarily the full installation details.
Names also vary. “Hob” is common in the UK, while “cooktop” is common in the US. A bathroom washbasin may be labelled BASIN, LAV or lavatory. WC means water closet and commonly identifies a toilet.
Electrical and plumbing symbols
Electrical plan symbols show where building services are located. They belong to installation or layout drawings. Circuit schematics use a different set of marks to explain how electrical components connect.
The examples below are common forms, especially on North American drawings. UK projects and drawings using international conventions may use different shapes or labels.
| Name | How the symbol is drawn | What it means |
| Socket or receptacle | A small circle crossed by two short parallel lines is a common US duplex-receptacle mark. | A power outlet. Extra letters identify special types or mounting conditions. |
| Light switch | Often an S beside a doorway; numbers or letters may be added. | A switch position and, where marked, its type. |
| Ceiling light | Commonly a circle with an X inside; other shapes identify different fittings. | A ceiling-mounted lighting point or fixture. |
| Wall light | Often a semicircle against a wall line, sometimes with short rays. | A wall-mounted light fitting. |
| Distribution board | A small rectangle with a label such as DB, PANEL or an equipment reference. | The location of an electrical distribution panel. |
| Smoke detector | Often a circle containing S or SD. | A smoke detector position. The legend confirms the detector type. |
Modifiers are also important. For example, WP can indicate weather protection, while GFCI identifies ground-fault protection on US drawings. These labels do not replace the equipment specification.
A community Wirings plug-in can help draw wiring routes in Sweet Home 3D. See the plug-ins and tools page for extension information. Wiring routes are separate from the symbols identifying devices.
| Name | How the symbol is drawn | What it means |
| Cold-water supply | A pipe route marked CW or C.W. | A cold-water supply line. |
| Hot-water supply | A pipe route marked HW, H.W. or HWS. | A hot-water supply line. |
| Waste or sanitary pipe | A line marked W, SAN or SS, depending on the legend. | A pipe carrying wastewater. |
| Vent pipe | A route labelled V or VT, often using a different line pattern. | A pipe that ventilates the drainage system. |
| Floor drain | A small circle or square with a grille-style mark, often labelled FD. | A drain receiving water from the floor. |
| Cleanout | An access-point mark labelled CO, FCO or WCO. | Access for cleaning a drainage pipe; letters may identify floor or wall placement. |
| Valve | A mark across the pipe, commonly two triangles meeting point to point for a gate valve. | A flow-control device. The exact mark identifies the valve type. |
Line patterns, pipe sizes and fixture references provide extra information. Read them together with the symbol rather than treating each mark separately.
Dimensions, notes and orientation
These architectural drawing symbols explain measurements, identify features and show the plan’s direction.
| Name | How it is drawn | What it means |
| Dimension line | A thin line with arrows or ticks at its ends and a number beside it. | The measured distance between two stated points. |
| Extension lines | Thin lines extending from objects towards a dimension line. | The exact points from which the measurement is taken. |
| Text annotation | A room name, label or written note placed beside a feature. | Information that the shape alone cannot explain. |
| Scale notation | Text such as 1:50 or 1/4 inch = 1 foot. | The relationship between drawing size and real size. |
| Compass rose or north arrow | A directional mark with an N label. | The orientation of north relative to the plan. |
Check where extension lines begin. A dimension between finished wall faces is different from one measured between wall centre lines.
At 1:50, one centimetre on the drawing represents fifty centimetres in the building. Resizing a printed page changes that relationship. Written dimensions remain the reference.
Sweet Home 3D supports dimension lines, text and a compass. A written scale note can be added as text, but it must match the actual print settings.
An elevation marker usually combines an arrow or triangle with a drawing reference. It points towards a separate view of a wall or building face. A section mark identifies an imaginary cut through the building and references the corresponding section drawing.
Using floor plan symbols in Sweet Home 3D
Sweet Home 3D draws walls and displays doors, windows and furniture in the 2D plan as you add them. So you do not need to draw each object’s outline by hand.
You can choose the relevant catalogue object, place it, and adjust its size and position. Add dimensions, room names and notes to make the drawing easier to read. Specialist objects may require additional catalogue libraries.
For a clear set of floor plan symbols, use consistent labels and explain any unfamiliar marks in a legend. Keep important measurements visible and avoid covering them with furniture or notes.
Explore the Sweet Home 3D floor plan software or follow the user guide to begin drawing your own layout.
