Plates 19 to 45
The scale drawings of a building are those which show the general layout of the building as a whole, locating the various features of the scheme, showing their relation to each other and giving the principal dimensions.
The scale drawings of the architect correspond in a sense to the assembly drawings of the machine designer. The characteristic of the architect's scale drawing is that it deals with general conditions and represents them by symbols rather than to show each feature exactly as it would appear. On Plates 19 and 20 are given these symbols which represent the various materials of construction and the fixtures which are usually found in the average building. The use of the plan symbols is illustrated on Plates 21, 22 and 23.
In general, when any feature is to be given afterward in a detail drawing, it is shown on the scale drawing merely by a quickly made symbol or a note. This is also true of features with which the builder is familiar and of which there will be no detail drawn. Do not indicate or dimension a feature in detail on the scale drawings when you intend later to make a large scale or full-size drawing of it, as this would be useless repetition.
For example, a fireplace is often located on the scale drawings by dimensioning to its center line on the plan and giving but few other figures. Then on the detail, everything is carefully shown and thoroughly dimensioned.
Thus it will be seen that the scale drawing is merely an indication while the accurate description is left for the detail.
The first thing to be decided about the so-called scale drawings is the scale at which they shall be drawn. This is fixed by the size of the building and the degree of fineness with which we wish to go into detail.
The average residence is drawn at a scale of 1/4" = 1' - 0", while a very large house must be drawn at a scale of 1/8" or 1/16" = 1' - 0". In deciding the size of the sheet to use, bear in mind the fact that the tracing cloth and blueprint paper of which we will hear later, come in widths of 30, 36 and 42 inches and sometimes wider. For sizes of other paper see page 10.
Plans are usually drawn with the front of the building toward the bottom of the sheet. If however the building is very deep and narrow, this may not be possible.
The principal plan should be laid out first. This in most buildings will be the first floor plan. Then the second, third, etc., floor plans are drawn, the basement plan usually being drawn last. This is almost always the best order of procedure, no matter what the building may be.
If the plan is to be symmetrical about a center line, this line is the first thing to be drawn and the plan worked out each way from it. Ink this center line to prevent its being erased when changes are made in the pencil drawing. Notice how the plan on Plate 32 has been worked from the several center lines. This is true also of elevations; see Plate 24.
After locating the center lines if there are any, lay out the rooms according to the previous approximately determined dimensions without indicating doors or windows. Draw the lines very lightly with an H pencil.
Now locate the doors and windows by center lines only. Second story windows are usually located directly above those of the first story but this is a matter to be determined by the design of the elevation as is also the width of these openings. After the elevations have been worked up, these features may be drawn on the plans, using the symbols of Plates 19 to 23 and 48 to 51.
The Width and Kind of Doorways and other openings, will be determined by the kind of building with which the draftsman is concerned or by the use to which the building will be put. Thus the front door of a residence should not be less than 3' - 0" wide and other outside doors not less than 2' - 10" wide. The communicating doors or those in the partition walls of a residence should be at least 2' - 8"wide to allow the passage of furniture. Closet doors may be 2' - 6" wide or less.
Door Heights will vary according to the design of the room. Sometimes a panel is placed above the door to give a feeling of additional height. It looks well in a residence to have both window and door heads at the same height above the floor if this can be done.
The term right-hand or left-hand door will be met with and should be understood. When you enter the house, if the door opens away from you and swings toward your right, it is a right-hand door; if it swings away from you and toward your left, it is a left-hand door. A knowledge of this is quite important in buying hardware.
Stock sizes of material often have a bearing on the design of a building. This is particularly true of residence work. For example, joist come only in even lengths, and if a room were 14' - 0" X 20' - 0" the nearest size of joist to span this room would be 16' - 0" long, leaving a waste of about 1' - 4" for each joist. If this room were made 13' - 4" or 15' - 4" wide the entire 14' - 0" or 16' - 0" joist could be used, for the joist extend into the wall about 4" at each end. Of course it is not always possible to prevent this waste.
Wall thicknesses are fixed by the material of which the wall is built. A frame wall is about 6 inches thick, a brick wall is 9, 13, 17, etc., inches thick and stone walls vary from 12 inches up.
Where soil pipes are placed in the walls, the pipe joints would project through the plaster and into the room if 4 inch studs or framing timbers were used. To prevent this the studs must be furred or framed out far enough so that the plaster will cover the pipe. Sometimes 6-inch studs are used in such a wall.
Window glass comes in even sizes and for this reason it is well to make all window frames of a size to take the stock glass, particularly if there are a great many of the lights to be furnished.
Due To The Fact That The Plans Of Different Draftsmen Would Be Likely To Have The Various Fixtures Etc. Represented In Widely Differing Manners, It Is Well To Accept A Standard Symbol For. Each Feature Of The Building. This Makes For, Ease In The Interpretation On The Drawings By Everyone Concerned. The Symbols Generally Used For Plumbing And Heating Fixtures Are As Shown . The Wiring Symbols Have Been Adopted By The National Contractors Association And The American Institute Of Architects And Are Accepted By Most Offices . The Symbols Used For Piping And For_ Building Material Are At Greater Variance, Most Offices Establishing Their. Own Standard According To The Needs Of Each Case. If This Is Done. A Key To These Symbols Should Accompany The Drawing.