Chapter XXV. Of the dimensions of the doors and windows

NO certain and determinate rule can be given for the height and breadth of the principal doors of fabricks, or concerning the doors and windows of rooms; because, in making the principal doors, the architect ought to accommodate them to the bigness of the fabrick, to the quality of the master, and to those things that are to be carried in and out of the same.

The best way, in my opinion, is to divide the space from the floor to the superficies of the joysts, into three parts and a half, (as Vitruvius teacheth in the sixth chapter of his fourth book) and allow two to the height, and one to the breadth of the opening, wanting the twelfth part of the height.

The antients used to make their doors narrower at top than at bottom, as is seen in a temple at Tivoli, and which Vitruvius also teacheth, perhaps for greater strength.

The place to be chosen for principal doors, is where a free access may be had to it from

p princip y all parts of the house.

The doors of rooms are not to be made wider than three foot, and six and a half high; nor less than two foot in breadth, and five in height.

IT is to be observed in making the windows, that they should not take in more or less light, ar be fewer or more in number, than what necessity requires: therefore great regard ought to be had to the largeness of the rooms which are to receive the light from them; because it is manifest, that a great room requires much more light to make it lucid and clear, than a small one: and if the windows are made either less or fewer than that which is convenient, they will make the places obscure, and if too large, they will scarce be habitable, because they will let in so much hot and cold air, that the places, according to the season of the year, will either be exceeding hot or very cold, in case the part of the heavens which they face, does not in some manner prevent it.

THEREFORE the windows ought not to be wider than the fourth part of the breadth of the rooms, or narrower than the fifth, and are to be made two squares and a sixth part of their breadth more in height. And altho’ the rooms in a house are made large, middling, and small, the windows, nevertheless, ought to be all equal in the same order or story.

To take the dimensions of the said windows, I like those rooms very much whose length is two thirds more than the breadth, that is, if the breadth be eighteen foot, the length should be thirty, and I divide the breadth into four parts and a half, one I give to the breadth of the void of the window, and two to the height, adding one sixth part of the breadth more; and according to the largeness of these I make those of the other rooms.

The windows above these, that is, in the second story, ought to be a sixth part less in “he height of the void, than those underneath; and in the same manner, if other windows are placed higher, they ought to diminish still a sixth part.

The windows on the right hand ought to correspond to those on the left, and those above directly over them that are below; and the doors likewise ought to be directly over one another, that the void may be over the void, and the solid upon the solid, and all fice one another, so that standing at one end of the house one may see to the other, which affords both beauty and cool air in summer, besides other conveniencies,

For greater strength, it is usual that the lintels or architraves of the doors and windows may not be overcharged with the weight, to make certain arches which are vulgarly called segments, which contribute very much to the duration of the fabrick.

T u windows ought to be distant from the angles or corners of the building, as has been said before, because that part ought not to be opened and weakened, which is to keep the whole edifice upright and together.

The pilasters or jambs of the doors and windows must not be less in thickness than the sixth part of the breadth of the void, nor more than the fifth,

IT remains now that we look into their ornaments.