Floor plan symbols and what they mean
A floor plan is a horizontal slice through a building, taken about four feet above the floor and looked at from above. Everything on it is drawn in a shorthand that has been settled for a century. Once you know the shorthand, a plan reads as easily as a sentence.
Walls, and why they are drawn heaviest
Anything the cut passes through is drawn with the thickest line: walls, columns, the sides of an opening. Anything below the cut but visible — a countertop, a bath, a floor finish — is drawn thinner. Anything above the cut, like a beam or an upper cabinet, is drawn as a dashed line. That hierarchy of line weight is the single most useful thing to know, because it tells you what is structure and what is furniture without a single label.
- Two solid parallel lines, pochéd or hatched between — a wall, drawn at its real thickness. External walls are usually thicker than partitions.
- A small solid square or circle — a column.
- A long dashed rectangle — a beam overhead, or the edge of a floor above.
- A dash-dot line — a centre line, used for setting out rather than for anything you can touch.
- A wall drawn with a diagonal break — the drawing is cut off there, not the wall.
Doors
A door is a gap in the wall with a thin leaf line and a quarter-circle arc. The arc is not decoration — it is the swing, and it tells you three things at once: which side the hinge is on, which way the door opens, and how much floor the open leaf sterilises. Furniture cannot go inside that arc.
| Symbol | What it is |
|---|---|
| Gap with one quarter-circle arc | Single hinged door, opening the way the arc sweeps |
| Gap with two arcs meeting in the middle | Double or French doors |
| Two overlapping parallel rectangles | Sliding door — one leaf passes the other |
| Two arcs on the same hinge, folded | Bi-fold, usually a wardrobe |
| A gap with no leaf and no arc | Cased opening — a hole with a finished frame, no door |
| Two quarter-arcs, one each side | Double-acting door, swings both ways |
The swing is the detail most often drawn wrong, and it is the cheapest mistake to fix on paper. A door that opens into a corridor blocks it; two doors that open into the same corner clash; a door hinged on the wrong side means you walk round the leaf every time you enter. Check every arc before you print.
Windows
A window breaks the wall with thinner lines running across the gap — typically three, representing the frame and the glass, though the exact convention varies between offices. Since the plan is a horizontal cut, the window symbol tells you nothing about its height or its sill; those live in the window schedule, which is why the schedule matters.
- Thin lines across the wall gap — a fixed or casement window.
- The same, with a small arc — a casement that opens, arc showing the hinge side.
- Two offset rectangles — a sliding or sash window.
- A wider gap with the wall stopping short — a bay or bow window, usually projecting outside the wall line.
Stairs
A stair is drawn as the treads seen from above, with a line running up the middle — the walking line — and an arrow. The arrow always points in the direction of travel upward, and it is labelled with the number of risers: UP 16R. Where a floor cuts through the flight, a diagonal break line shows which part belongs to this storey and which to the next.
On the upper floor the same stair reappears with a DN arrow pointing the other way. If a plan shows a stair going up and no corresponding stair coming down on the floor above, something is wrong. See stair dimensions for how the flight is actually sized.
Fixtures and fittings
| Room | Symbol | Reads as |
|---|---|---|
| Bathroom | Rectangle with a rounded end | Bath |
| Oval or circle on a small rectangle | Basin | |
| Oval with a rectangular cistern behind | WC | |
| Square with a diagonal or a small circle | Shower tray, circle being the drain | |
| Kitchen | Rectangle with two squares inside | Double sink |
| Square with four circles | Hob or cooker | |
| Plain square against the wall, labelled | Fridge, dishwasher, washing machine | |
| Anywhere | Dashed rectangle along a wall | Wall cabinet above the cut |
| Rectangle with a diagonal line | Worktop or counter run |
Fixture symbols are the least standardised part of a plan. They vary by country, by office and by drawing package, and nobody minds much — a bath drawn slightly differently is still obviously a bath. Structure and openings are where the conventions are strict.
Dimensions, levels and annotation
- A line with ticks or arrows at each end — a dimension, read in the units the drawing declares. The ticks are slashes in architectural practice, arrowheads in engineering.
- A circle with a letter and number, D1 or W3 — a door or window mark, tying that opening to a row in the schedule.
- A triangle or circle with a figure like +2.75 — a level, given relative to a datum, usually the ground floor at 0.
- An arrow with a letter at each end of a line across the plan — a section mark. It shows where a vertical cut was taken and which way you are looking.
- A circle with a tail, numbered — a detail reference, pointing at a larger-scale drawing elsewhere in the set.
- N with an arrow — north. Always check it before you reason about which rooms get morning sun.
DrawHousePlan draws all of this for you. Walls come out at real thickness with the right line weight, doors get a swing you can flip, windows and doors are marked automatically and collected into a schedule, and the stair gets its walking line and its UP nR label without you drawing a single tread. Print the set and it comes out at a true architectural scale.
Reading a plan you did not draw
Work in this order and an unfamiliar plan gives itself up quickly: find the north arrow and the scale, trace the outside wall to get the shape of the building, find the front door, then find the stair — those three tell you how the house is entered and how it is circulated. Only then read the rooms. Most people start by reading room labels, which is why they miss that the only route to the kitchen runs through a bedroom.
More on that in how to read a floor plan.