Window symbol on a floor plan

A window on a floor plan is a break in the wall with thin lines across it: a line at each side where the wall stops, one or two lines for the glass, and a sill line on the outside face. A tag such as W1 beside it points to the window schedule. Below is why the symbol looks like that, each type of window drawn in plan and in elevation, and what to check on your own plan.

Why a window looks like that on a plan

A floor plan is drawn as if the house were sliced through part of the way up the walls, high enough to pass through the windows, and seen from above. Where the slice meets solid wall, the wall is drawn heavy. Where it meets a window, it passes through the glass, so you see the frame and the glass as thin lines, and below them the sill.

The jamb lines, where the wall stops at each side of the opening.
The glass, drawn thin along the middle of the wall. Some offices draw two lines, for the frame and the glass.
The sill, a line on the outside face where the sill projects to shed rain.
The window mark. W1 sends you to the window schedule for its size, type and sill height.

An illustrative drawing of the convention, not to any scale and not a drawing of any house. The plan cut passes through the window, so the glass shows on the plan and the wall above and below it does not.

Window types in plan

The plan shows how a window opens, not how big it is. The size, the frame and the glass are in the schedule.

Fixed window Jamb lines where the wall stops, one glass line, and a sill line on the outside. Nothing opens, so nothing else is drawn.
Sliding window Two sashes on two tracks, offset so they overlap in the middle. The common aluminium window in a Philippine house.
Casement window A sash hinged at the side, drawn swung open with a dashed arc, like a small door. The arc shows which way it opens and what it clears.
Awning window Hinged at the top and pushed out at the bottom. In plan it looks almost fixed, with the open sash sometimes dashed outside the wall. The elevation tells you more.
Jalousie window Short slanted lines across the opening for the glass or aluminium blades. Cheap and airy, and hard to seal against driving rain.
Bay window The window projects out from the wall line in three faces. It stands past the wall line, so on a tight lot check it against the setback.
Corner window Glass on both walls meeting at the corner, with no wall or post between. The structure has to carry the load another way.
High window A window above the plan cut, high in the wall. The wall is drawn solid and the window dashed, often noted HW with its sill height.

The same windows in elevation

An elevation is the house seen straight on from one side. It shows the shape of each window and, with dashed lines, which way it opens. Read the plan and the elevation together: the plan says where the window is, the elevation says what it looks like and where it is hinged.

Casement, in elevation Dashed lines meet in a point on the hinged side. Read the point as the hinge.
Awning, in elevation The point is at the top, because the sash is hinged at the top.
Sliding, in elevation Two sashes with an arrow on the one that moves.
Jalousie, in elevation Horizontal lines for the blades, close together.

The window schedule

Every tag on the plan, W1, W2 and so on, is a row in the window schedule, usually on the same sheet or on the door and window sheet. Windows of the same size and type share a tag, so the plan may show W2 four times. The schedule is what the fabricator quotes from.

Column	What it tells you
Mark	The tag on the plan, such as W1.
Type	Fixed, sliding, casement, awning or jalousie, often with an elevation drawn beside it.
Width and height	The size of the opening or of the frame. The sheet says which, and in what unit.
Sill height	How far the bottom of the window is above the finished floor. It decides whether furniture fits under it and whether a child can reach it.
Frame and glass	Aluminium, uPVC or timber, and clear, tinted or frosted glass. Frosted is usual in a CR.
Quantity	How many of that window there are, which should match the tags counted on the plans.
Remarks	Screens, grilles, and anything else the fabricator needs to know.

Two rules the windows on a house plan meet

Enough window for the room. The National Building Code asks that a room without artificial ventilation has windows opening to at least one tenth of its floor area (PD 1096 Section 808). Take the room size from the plan and the window sizes from the schedule, and the room size checker does the sum.

Distance from the neighbour. A wall with windows looking onto the next lot must stand at least 2.00 m from the boundary (Civil Code Article 670). On a small lot this decides which walls can have windows at all. The right of way and easements guide sets out the article and its exceptions.

Checking the windows on your own plan

Count the tags. Every window on the plan should have one, and every mark should be in the schedule.
Look for cross-ventilation. A room with windows on two opposite or adjacent walls cools far better than one with a single window. The guide to designing for the Filipino climate explains why.
Check the swing. A casement or awning window that opens onto a walkway, a carport or a neighbour's wall can hit someone or not open at all.
Check the furniture. If the bed or the kitchen counter sits under a window, the sill height in the schedule has to clear it.

Philippine houses have used windows to cool rooms for centuries. The bahay kubo propped its awning windows open on a rod, and the bahay na bato slid whole walls of capiz aside. The full floor plan symbols legend has every other mark on the sheet, and the other symbols drawn in detail are sliding doors and stairs.