Of the Solidity of Buildings. ARTICLE I.Of the Choice of Materials. THE Materials of which Vitruvius speaks are, Stone, Brick, Wood, Lime, and Sand. All the Stones are not of one sort, for some are soft, some harder, and some extreamly hard. Those that are not hard are easily cut, and are good for the Inner Parts of the Buildings, where they are cover'd from Rain and Frost which brings them to Powder, and if they be made use of in Buildings near the Those that are indifferently hard, are fit to bear Weight; but there are some sorts of them, that easily crack with the heat of the Fire. There is likewise another sort of Stone, which is a kind of Free-Stone; some are Red, some Black, and some White, which are as easily cut with a Saw as Wood. The best Bricks are those which are only dry'd and not baked in the Fire; but there are many Years required to dry them well: and for this Reason, at Utica, a City of Africa, they made a Law, That none should make use of Bricks which had not been made five Years: For these sort of Bricks, so dry'd, had their Pores so close in their Superficies, that they would swim upon Water like a Pumice-Stone; and they had a particular Lightness, which made them very fit for all sorts of Buildings. The Earth of which these Bricks were usually made was very Fat, and a sort of White Chalky Clay without The Woods which were made use of in all Buildings, are Oak, Poplar, Beech, Elm, Cypress, Firr; but some of them are not so proper for Building as others. The Firr, because it has great plenty of Air, and Fire, and but little Earth and Water, is light, and does not easily bend; but is very subject to Worms and Fire. The Oak which is more Earthy lasts for ever under Ground; but above Ground is apt to cleave. The Beech which has little of Earthiness, Humidity and Fire, but great plenty of Air, is not very solid and easily breaks. The Poplar and the Linden Trees are only good for light Work, they are easily cut and so finest for Carving. The Alder is good to make Piles of in Marshy Places. The Yoke-Elm is likewise pliable, and yet very strong; this is the Reason that they made Yokes for their Oxen of them in Old Time. The Pine and the Cypress have this defect, that they easily bend under any Weight, because of their great Humidity; but they have this Advantage, that their Humidity does not engender Worms, because of their Bitterness which kills them. The Juniper and the Cedar have the same Vertue of hindering Corruption: the Juniper by its Gum, which is call'd Sandarax, and the Cedar by its Oil call'd Cedrium. The Larch-Tree has likewise the same Vertue, but its particular property is, that it will not burn. There is a remarkable Story of this Wood, which is, That when Julius CÆsar besieg'd a Castle at the Foot of the Alpes, there was a Tower built of this Wood, which prov'd the Principal Defence of the Place. He The Olive-Tree is likewise very serviceable, if it be put in the Foundations, and Walls of Cities; for after it has been singed a little, and interlaced among the Stones, it lasts for ever, and is out of all danger of Corruption. Lime is made of White Stones or Flinty Pebbles, the harder the Stones are which 'tis made of, the better it is for Building. That which is made of soft Spongy Stones, is proper for Plastring. There are five sorts of Sand; viz. Sand that is dug out of the Ground, River Sand, Gravel, Sea-Sand, and Pozzolana, which is a Sand peculiar to some Parts of Italy. The best Sand is that which being rubb'd between the Hands makes a little Noise, which that Sand does not, which is Earthy, because it is not rough. Another Mark of good Sand is, that when 'tis put upon any The Sand which is dug out of the Earth has all these Qualities, and is esteem'd the best. Vitruvius makes four sorts of it; viz. White, Black, Red, and Bright like a Carbuncle. If it happen that there be no good Place to dig Sand in, we may make use of Sea-Sand, or River-Sand, which is likewise better for Plastering than the Sand which is digged, which is excellent for Building, because it drys quickly. Gravel likewise is very good, provided the grosser Parts be taken away. Sea-Sand is worst of all, because 'tis long adrying; and for this Reason, where 'tis made use of in Building, they are forc'd to desist sometimes till it dry. The Sand which is found near Naples call'd Pozzolana is so proper to make good Mortar, if it be mixed with Lime, that not only in the ordinary Fabricks, but even in the very bottom of the Sea it grows into a wonderful hard Body. In Old Times they made use of it for Moles or Ports ART. II.Of the Use of the Materials. THE first thing we should have a Care of before we begin to build, is, to have the Stones dug out of the Quarry before they be used, and to expose them in some open Place, to the end that those which are endamaged by the Air, during this Time, may be put in the Foundation, and those that prove Durable and Good may be kept for the Walls above Ground. We must likewise have a great care of the Wood which we make use of; That it be cut in a seasonable Time, which is in Autumn and This superfluous Humidity endamages Trees so much, that we are sometimes constrain'd to make a hole at the foot of the Tree and let it run out, which is the occasion of the Practice which is observ'd in cutting of Wood for Building, to Tap that Tree at the Foot, cutting not only the It is likewise easie to judge of what great Importance the draining of this superfluous Humidity is for strengthning Lib. 1. Lib. 1. They likewise never made the top of their Walls with Brick; for the Brick of the Ancients not being baked, this part of the Wall would have been easily endamaged; for this reason they built it with Tiles, a foot and a half high, comprizing the The Walling with Brick was so much esteem'd among the Ancients, that all their Fabricks, as well publick as private, and their most beautiful Palaces were built with them. But that which principally made this sort of Building be esteem'd, was its great Duration; for when expert Architects were called to make an Estimate of Buildings, they always deducted an 80th. part of what they judged the Building cost for every Year that the Wall had been standing, for they supposed that the Walls could not ordinarily endure more than Fourscore Years; but when they valued Buildings of Brick, they always valued them at what they cost at first, supposing them to be of an Eternal Duration. The way to know whether the Lime be well Quench'd, is thus: You Lib. 7. Lib. 2. Lib. 7. ART. III.Of the Foundation. Lib. 6. To lay the Foundation well, you Lib. 1. Lib. 3. Lib. 1. To make the Binding of the Stones the stronger in the Foundation of great Fabricks, you must put Piles of Olive a little singed and placed very thick from one Parement or Course to another, which serves, as it were, for Keys and Braces; for this Wood so prepar'd, is not subject to Worms, and will endure for ever, either in the Earth or in the Water, without the least Damage. Lib. 6. ART. IV.Of the Walls. Lib. 4. The Net-Masonry is that which is made of Stones perfectly squar'd in their Courses, and are laid so, that the Joints go obliquely, and the Diagonals are the one Perpendicular, and the other Level. This is the most pleasing Masonry to the Sight, but The Masonry call'd the Bound-Masonry, is that, as Vitruvius explains it, in which the Stones are plac'd one upon another like Tiles; that is to say, where the Joints of the Beds are Level, and the Mounters are Perpendicular; so that the Joint that mounts and separates two Stones falls directly upon the middle of the Stone which is below. Some Authors call this sort of Masonry Incertain, but they are mistaken; for they read Incerta instead of Inserta; it is not so Beautiful as the Net-work, but it is more solid and durable. See the Figure BB. Table I. The Masonry which Vitruvius says is particular to the Greeks, is that, where after we have laid two Stones, each of which make a Parement or Course, another is laid at the end, which makes two Parements or Courses, and all the Building through observe this Order. This may be call'd Double-Binding; for the Binding is not only of Stones of the same The manner of Walling by unequal Courses call'd Isodomum by the Ancients, differs in nothing from the Masonry call'd Bound-Masonry, but only in this, that the Stones are not hewed. See Figure D. Table I. The other manner by unequal Courses call'd Pseudisodomum is also made of unhewed Stone, and laid in Bound-Work, but they are not of the same thickness, and there is no equality observ'd, but only in the several Courses, the Courses themselves being unequal one to another. See Figure A. Table I. The Masonry which is fill'd up in the middle, call'd by the Ancients Emplecton, is likewise made of unhewed Stone and by Courses, but the Stones are only set in order as to the Parements or Courses, but the middle is fill'd up with Stones thrown in carelesly among the Mortar. See Fig. FF, GG, H. Table I. For this reason Vitruvius proposes another sort of Masonry, which may be call'd the Compound Masonry, for it is all the former together, of Stones hewed and unhewed, and fastned together with Cramp-Irons. The Structure is as follows: The Courses being made of hew'd Stone, the middle place which was left void is fill'd up with Mortar and Pebbles thrown in together; after this they bind the Stones of one Parement or There are many Precautions to be given to make the Masonry more firm and durable, and these Precautions are common to all the different sorts of Masonry. Lib. 1. Lib. 6. There are also two ways of strengthning the Walls, which are either to ease them of their own weight, or of that of the Earth which they are to support. The first way of easing is in those Places where there are void spaces, as above Doors or Windows. These easements may be made two different ways; the first is to put over the Lintel which supports the Wall, which is over the void space of the Gates and Windows, two Beams, which lying or resting below directly upon Pieds-droits or Piers meet together above. The other way is, to make directly over the void spaces Vaulted Arches with Stones cut corner-ways and tending to one Center. For the Walls be so strengthned by the means of these easements, that part of the Wall which is below will not sink at all being easied of the load of the part that is above, and if some de The second way of easing, is, for Walls that are made to support the Earth; for, besides the extraordinary thickness which they ought to have, they should have likewise Buttresses on that side next the Earth, so far distant one from another as is the breadth of the Wall; they ought likewise to have an Emparement or large Foundation which must be equal to the height of the Wall, so that they go diminishing by degrees from the bottom to the top, where they come to equal the height of the Wall. Lib. 1. Lib. 6. ART. V.Of Flooring and Ceiling. THere are four sorts of Flooring, some are upon the Superficies of the Ground, others between two Stories, others make the Roof of the House in Plat-form, and the last is Plat-Fond. To make those Floors that are upon the Ground, you must first make the Earth smooth and plain, if it be firm and solid, if not, it must be beaten with a Rammer with which they ram down their Piles; and after having cover'd the Earth with the first Lay or Bed, call'd Statumen by the Ancients, which was of Flinty Stones about the bigness of ones Fist, among which was mixed Mortar made of Lime and Sand. Then they laid the second Bed, which they call'd Rudus, which was made of lesser Stones, of which there were three Parts for one The Greeks had a way of making their Lib. 7. For the Floors which are between two Stories, there must be a particular care taken, that if there be any Partition below it, that it may not To make these Floorings, the Boards must be nailed at each end upon every Joist, to the end they may not warp; these Boards or Planks being cover'd with Straw, to hinder the Lime from wasting the Timber, the first Bed must be laid, made of a mixture of Mortar and little Stones a hand breadth, which must be beaten a long time with Iron-Levers, and so it must make a solid Crust which must be nine Inches thick; upon it shall be laid the Noyau or Ame, which must be at least six inches thick: It must be made of Cement, with which must be mix'd one part Lime for two parts Lib. 7. The under part of the Flooring, and the Plat-Fonds, must be made also with great Care. To make the Plat-Fonds or Flat-roofs, in the The Ancients sometimes made double Lib. 5. The Corniches which are made use of under the Plat-Fonds, ought to be little, lest their great Jetting out, or Projecture should make them heavy, and apt to fall. For this Reason they ought to be made of pure Stuck of Marble, without any Plaster, that all the Work drying at the same time, may be less apt to break. ART. VI.TO make Plaster that it may continue a long time, and not crack; you must take Care to lay it on Walls that are very Dry; for if the Walls be Moist, the Plastering being expos'd to the Air, and drying faster than the Walls, will crack. They took likewise a great deal of Pains to run several times over and beat the Plaster, which gave it a Hardness, a Whiteness, and Polish'd it so well, that it shin'd like a Mirror. These Plasterings so made, serve to Paint in Fresco upon; for the Colours being laid upon the Mortar before it was dry, pierced it, and Embodied with it; so that the Painting could not be defaced though it were wash'd; which would easily be wash'd off if the Mortar were dry. For the Plastering of low and moist places, they had a great many other Lib. 7. But as to the Inward-parts of the House, when the Ground without was higher than the lowermost Flooring; they run up a little narrow Wall against the great one, leaving betwixt the two Walls only the distance of a Channel or Sewer, which they made lower than the Flooring, to receive the Water which might be gather'd against the Walls, and let it run out; When the Place was too narrow to permit those Counter-Walls to be made within, they put hollow Tiles one upon another against the Wall, and placed and plaster'd them over with Mortar and Stuck. These Tiles which were Pitch'd over within, and were Demi-Channels, let the Water fall down into the Sewer, which sweat from the great Wall, and so let all the Vapours, which were engendred by Humidity, go out at the Vents. ornament. |