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How do you draw a window or door on a floor plan?

An opening on a floor plan isn't just a gap in a line. It has a width, a position along the wall and — for a window — a sill height, and all three figures need to be there if the drawing is going to be any use.

The three figures an opening needs

A line with a gap in it isn't enough. For a contractor, a window supplier or you yourself to actually use the drawing, three measurements need to be in place:

• The width. Measured either as the rough opening (the hole in the wall itself) or as the clear opening measurement (the gap you can actually walk or see through once the frame and reveal are in place). The two figures aren't the same — a 90 cm rough opening typically becomes an 82.5-85 cm clear opening once the door is fitted.
• The position along the wall. Either centred on the wall, spaced evenly alongside other openings, or set at a specific distance from the nearest corner. Position decides what can stand next to it — a window 40 cm from the corner doesn't leave much room for a tall cabinet there.
• The sill height (windows only). The height from the finished floor to the underside of the window. It decides whether you can put a piece of furniture in front of the window, whether a child can see out, and whether a bathroom window gives you any privacy.

How high does a window typically sit?

There's no fixed rule, but there are clear patterns depending on what the room is used for:

• Living rooms and bedrooms: a sill height around 80-100 cm is common. It leaves room for a radiator or a low piece of furniture under the window, while you can still see out sitting down.
• Kitchens: often a bit higher, 90-110 cm, because a kitchen counter typically sits around 90 cm — the window is set to start where the worktop ends.
• Bathrooms: often higher still, 120-150 cm or more, for privacy and because there's usually room needed for a vanity unit or a radiator underneath.
• Basement and roof windows: varies a lot depending on how high the room's walls even reach, and whether the window sits in a sloped ceiling.
• Floor-to-ceiling windows and patio doors: sill height 0 cm — the window starts at the floor. Special safety-glass requirements often apply here, because there's no sill to stop a fall.

These figures are typical ranges, not standards. If you're choosing windows for a new build or an extension, it's the architect's or window supplier's job to settle on the right height based on the room's function, furniture layout and any regulatory requirements — not a rule of thumb from an article.

How is an opening positioned correctly when several share a wall?

If a wall has more than one opening — two windows in a living room, or a window and a door out to a terrace — there are typically three ways to place them:

1. Centred. One opening in the middle of the wall. Simplest, and what looks most balanced in a small room.
2. Evenly spaced. Several openings with equal gaps between each other and to the corners. Typically used for a row of windows in a long façade.
3. Dimensioned from the corner. The opening is set at a specific distance from the nearest corner — necessary when the position has to line up with something else, such as a chimney breast, a load-bearing column, or a kitchen unit that needs to stand next to it.

If you're deciding for yourself where a new opening should go — during a renovation, say — think about the position together with what's going to stand on each side inside: a door that opens straight into a corner blocks a piece of furniture that could otherwise have stood there.

Symbols you'll come across on a floor plan

Most floor plans use a fixed set of symbols for openings, whatever software they were made in:

• Door: a line from the hinge side with a quarter circle (an arc) showing which way and how far the door swings. The arc tells you the swing direction — but it doesn't come automatically from a scan; see the section below.
• Window: typically two or three parallel lines across the wall line, with no arc, because a window doesn't normally swing out into the room the way a door does.
• Sliding or folding door: a dashed or arrow-tipped line along the wall instead of an arc, because it moves along the wall rather than out into the room.
• Opening without a door (a doorless passage): a gap in the wall line with no arc or line pattern — just a break in lines that would otherwise show a solid wall.

Can an app tell on its own how a door opens?

No. A scan — whether it's made with LiDAR or a camera — sees that there's a gap in the wall, and often whether there's a door leaf in it. But it can't see which way the door usually swings, because that depends on where the hinges are — something that's typically only clearly visible when the door happens to be open at the exact moment the scan passes it. So the swing direction is something you always have to set yourself afterwards, whichever app you use.

Measurement errors that cost the most on an opening

A couple of centimetres of error on an ordinary wall line rarely does any harm. On an opening, the margins are smaller:

• Too narrow a width means an ordered door or window simply won't fit the hole, and the rough opening has to be widened — expensive, dusty work once the house is finished.
• The wrong sill height on a window can mean a piece of furniture you'd planned to put under it hits the frame.
• The wrong position along the wall can mean a window ends up in the middle of a planned run of wall cabinets instead of over the sink.

If the measurements are going to be used for an order — a new window, a new door — always measure yourself with a tape measure as a final check, whatever the drawing's source.

What HouseSense does

On HouseSense's drawing board you draw an opening straight onto the wall with your finger and then set whether it's a window, a door or a doorless passage. Position can be set to centred, evenly spaced alongside other openings on the same wall, or at a specific distance from the corner — and for windows, the sill height is set as part of the same step. If you've scanned the home with LiDAR instead of drawing it, the app finds the openings' width and position from the scan on its own, but sill height and swing direction are still added by you, because those are the two things no scan can see.