Guides · Doors · 14 min read · Updated September 2026

Doors inside the house

The tradition read the front door as the mouth of the house and every door inside it as a smaller mouth, and most of what it says about them is about hinges. Which way a door should swing and why; the four faults of interior doors, the door that faces a door, the three in a line, the bedroom’s opposite the bathroom’s; how many doors a room can bear before it is a corridor; the sizes a door should have; what a closed door does to sound; and the one rule about the bathroom that is a smell and not a leak.

Oriented SE 117°

Wood

Fig. 01 A door ajar in the sun. The tradition’s interior doors are read by what they show when they open.

The front door has its own guide because the tradition gave it the most rules; the doors inside a house have had none, though the same manuals give them a page and a designer gives them most of a plan. An interior door decides what a room shows when it opens, what two rooms know of each other, whether a line runs through the house, and whether a room is a place or a passage. This guide gives the tradition’s rules for the hinge, the four faults it names, the counting rule for doors in a room, and the sizes and sounds the joiner and the acoustician add.

The mouth, and the smaller mouths

The yang-house manuals read the front door as the mouth of qi and the doors inside as the mouths of the rooms, and the Ten Books of the Yang House, which the texts page describes, gives the interior doors their own rules: a door should open into the room and not against it, so that the room is seen and the leaf does not stand in the way; it should not face another door across a passage, nor stand in a line with the front door and the back; it should not open onto a stair, a stove or a lavatory; and a room should have as few of them as it can, since every door is an opening through which the room’s breath leaves. The Qing manual that made the door one of three essentials with the main room and the stove, the Three Essentials of the Yang House, treats the interior doors as the smaller members of the same family, and Knapp’s survey of the old dwellings finds the rules kept in the placement of every door in a courtyard house, where the doors of the wings open toward the court and never face one another across it. The rules were written for a house of leaves on wooden pivots, and the joiner’s version of them, which this guide gives, is the same set with hinges.

Four faults, and the hinge that answers each

Fig. 01 Four faults of interior doors and their answers, each a plan of a small room or a piece of corridor with the fault above and the answer below, drawn ghosted. A: the swing. A door hung so that it opens onto the wall shows the visitor a wall and hides the room until they are inside it; hung on the other jamb it opens to show the room, which is the tradition’s first sight and Alexander’s corner door. B: two doors facing each other across a corridor, the door-to-door fault, give each room the other’s comings and goings; offset by the width of a leaf they do not. C: three doors in a line, the front door, an inner door and a back door or window, give the house a single line through it, the through-hall fault; a screen, a turn or one door moved breaks it. D: the bedroom door opposite the bathroom’s, which the manuals dislike for the smell and the sound and a designer for the same reasons; one of the two turned to open the other way, or kept closed, answers it. None of the four needs a wall moved; all of them can be answered with a hinge. The rooms are three metres by two and a half and the corridor a metre wide; the leaves are eighty centimetres. The faults are the yang-house manuals’ and the answers are the joiner’s, which is why the drawing shows hinges and not cures.

The four faults the manuals name most are drawn above, each with the answer beside it, and none of them needs a wall moved. The first is the swing. A door hung so that it opens onto the wall shows the visitor a wall and hides the room until they are round the leaf; hung on the other jamb, it opens to show the room, which is the tradition’s first sight, the entrance guide’s rule for the front door, and Alexander’s corner door, the pattern that puts a door near the corner of a room so that the room opens before the person entering it and the path across it hugs one wall. The second is the door that faces a door across a corridor, the dui men sha the sha catalogue gives, which lets each room see and hear the other’s comings and goings; offset by the width of a leaf, the two do not. The third is three openings in a line, the front door, an inner door and a back door or a window, which the manuals call the through-hall fault, chuan tang, and read as qi entering and leaving in one breath; the answer is a screen, a turn, or one door moved a metre, and the small apartments guide gives the screen. The fourth is the bedroom door opposite the bathroom’s, which the manuals dislike for the smell and the sound and a designer for the same reasons; one of the two turned to open the other way, or kept closed, answers it, and a bathroom door that opens onto a corridor rather than a bedroom is the plan the bathroom page asks for.

Design observation · The joiner’s numbers

A designer hangs a door with three numbers. The clear opening is eighty to ninety centimetres for a room and eighty-five at least where a wheelchair may pass, which Panero gives and the accessibility standards require; the height is two metres to two metres ten; the swing needs its own quarter circle clear of furniture, which is why a door that opens onto the back of a sofa or the side of a bed is a door hung the wrong way. A sliding or pocket door has no swing and is the tradition’s screen made permanent, the right answer in a small room and the wrong one where sound matters, since a slider seals badly. Where the swing is wrong the hinge is moved; where the door is wrong the door is closed off and plastered, which is cheaper than a practitioner’s cure and lasts longer.

The wall that opened

Fig. 02 The hall’s front as the tradition built it, in elevation: a row of six lattice doors between the columns, each a lattice of wood above and a solid panel below, hung on pivots at top and bottom so that any of them can be lifted out. The whole front of the principal hall was doors, and the household opened as many as the season asked: two in spring, all six in summer, when the hall became a roofed part of the court, and none in winter, when paper on the lattice let the light through and kept the wind out. Two are lifted out here and the court is seen through the gap. It is the door the yang-house manuals assume when they say a hall should open to its court and face south, and the reason their rule about a hall is not a rule about a doorway: the hall had no doorway, it had a wall that opened. The modern equivalents are the folding and sliding glass walls of a living room onto a terrace, and the room guides treat them as the tradition treated the lattice, as a front to be opened by the season and screened by the hour. Knapp gives the lattice doors of the halls of the north and the south with their patterns; Ruitenbeek’s carpenter’s manual gives their making. The lattice was papered in winter and open in summer; glass came late.

The manuals’ hall had no doorway, and a reader who pictures one misreads every rule about it. The front of the principal hall of a courtyard house was a row of lattice doors between the columns, geshan, each a lattice of wood above and a solid panel below, hung on pivots at the top and bottom rather than hinges, so that any leaf could be lifted out of its socket by two people and stood against a wall; Knapp gives the patterns of the lattice, which were the carpenters’ pride and a lineage’s signature, and Ruitenbeek’s carpenter’s manual gives their making. The household opened as many as the season asked. In winter every leaf stayed in and the lattice was papered, so that the hall had the light of six windows and the wind of none; in spring the two centre leaves came out; in summer all six went out and the hall became a roofed bay of the court, with the breeze through it and the elders’ chairs looking down the axis to the gate, which is the houses essay’s courtyard used as it was meant to be. When the yang-house manuals say that a hall should open to its court and face south, and when the four animals essay puts the bright hall in front of it, they are describing this wall, and the rule about the hall is a rule about a front that opened, not about a door. The modern flat has the wall’s descendants and does not know it: the folding or sliding glass wall of a living room onto a terrace or a garden is the lattice front in glass, and the room guides treat it as the tradition treated the lattice, a front to be opened by the season and screened by the hour, with the curtain doing in the evening what the paper did in winter. The windows guide gives the glass its physics; this guide gives it its ancestor, and the ancestor’s rule: a front that opens is not a doorway, and the sofa does not turn its back on it.

How many doors a room can bear

Fig. 03 How many doors a room can bear. A: a living room of five metres by three and three-quarters with four openings, one in each wall, the plan a converted house often ends up with; the paths between the doors are drawn, and they cross the room in every direction, so that there is no wall a sofa can stand against without a door behind it or a path across its front. The tradition’s word for the room is a corridor, and the manuals’ rule that a room with three or more doors leaks is this drawing. B: the same room with two doors, one closed off and made a wall, one turned to the corner, the paths gathered to one side of the room and three walls free; the sofa has its back to a wall and the door in view, which is the command position, and the room has a centre, which is the bright hall. The difference between the two is two hinges and a sheet of plasterboard. The counting rule is the yang-house manuals’, where a door is a mouth and a room with too many mouths cannot hold its breath; the designer’s version is Alexander’s, that the paths through a room should be kept to one side of it so that the rest is a place. Both drawings are to the same scale.

The counting rule is the one the manuals state most plainly and the converted house breaks most often: a room with three or more doors is not a room. The drawing above gives a living room with an opening in each wall, the plan a house acquires when a kitchen is knocked through, a conservatory added and a hall opened up, and draws the paths between the doors; they cross the room in every direction, and there is no wall a sofa can stand against without a door behind it or a path across its front. The tradition’s word for such a room is a corridor, and its rule that a room with too many mouths cannot hold its breath is a description of the drawing. The same room with two doors, one closed off and made a wall and one turned toward a corner, gathers the paths to one side and leaves three walls free; the sofa has its back to a wall and the doors in view, which is the command position, and the room has a centre, which is the bright hall. Alexander’s pattern language reaches the same rule from the paths: keep the circulation through a room to one edge of it, so that the rest can be a place. The difference between the two drawings is two hinges and a sheet of plasterboard, and it is the largest change a house can be given for the smallest sum.

Evidence · What a closed door does

The manuals close doors against smell and sound, and the acoustician measures what the closing does. Egan’s handbook gives the figures: a hollow-core door with a gap beneath it stops next to nothing, a solid door with the gap sealed stops a conversation, and the gap matters more than the door, since sound goes round a leaf before it goes through one. The World Health Organization’s night noise guideline, which the quiet guide draws, is met in a bedroom behind a solid door and missed behind a hollow one on the same corridor. The tradition’s rule that the bedroom door should not face the bathroom’s is, in the acoustician’s terms, a rule about a door that will be opened and closed all night by other people; turning it is the answer, and a solid leaf with a seal is the rest of it.

The doors inside, in order

Count them. Two doors to a room; a third makes a corridor. Close one off before buying any furniture.
Hang them to show the room. The leaf against the near wall, the room opening as the door does; move the hinge if it does not.
Offset the facing pairs. Two doors across a corridor a leaf’s width apart, so neither room sees into the other.
Break the line. No straight run from the front door through an inner door to a back door or a window; a screen or a turn.
Turn the bathroom’s. Onto the corridor, not the bedroom; solid leaf, sealed, extractor behind it.
Size them from the ruler. Eighty to ninety clear, two metres up, smaller than the front door and not all alike.
Nothing onto a stair or a stove. A door that opens onto a step or a flame is the one fault the joiner and the manuals both call dangerous.