As noted in Chapter 5, dimensioning is done in a hierarchical manner. Buildings, structural framework, rooms, and fixtures are dimensioned in decreasing size order. The actual number of dimensions on a plan is dependent upon how much latitude the designer affords the contractor. A very detailed and dimensioned plan gives the builder little room for deviation from the original design. However, if only a few key dimensions are shown, the builder is trusted to determine exact locations of interior components. A good guideline for dimensioning falls somewhere between these two approaches. An overdimensioned plan allows the builder little freedom to make field adjustments or substitute cost-saving techniques. However, too few dimensions can produce a lot of guesswork and increase the chances for error in the field and in coordination between subcontractors.
Dimensioning Techniques:-
Dimensions are placed on the floor plan as shown in it. Note that the dimension lines are drafted lighter than wall lines and are generally done as a continuous group or string of numbers along a line. The extension line begins slightly away from the object (a minimum of 1⁄16 inch or 1.58 mm), never touching it. It extends about 1⁄8 inch (3.17 mm) beyond the dimension line. Arrows, dots, or 45-degree tick marks (most common) are used at the extension line and dimension line junction. The arrows, dots, or tick marks are drawn with a thicker and/or darker line to make them stand out graphically. The 45-degree tick marks are drawn in a consistent direction. However, some draftspersons slope the tick marks for vertically read dimensions from left to right and horizontally read dimensions from right to left. When using the computer, any of these three graphic symbols (arrows, dots, or ticks) can be called up and consistently inserted for all dimensions.
All dimensions in this floor plan are to the face of a stud,except for the wall between the closets.It is dimensioned to the centerline of the wall.The centerline technique can also be used to locate exterior windows and doors.as seen in this example,Note that the dimensions on this partial floor plan are placed outside of the spaces.The extension lines do not touch the walls,and dark 45 degree tick marks indicates the extent of the dimension.
Dimension on a floor plan usually requires two or three continues dimension lines to locate exterior walls,wall jogs,interior walls,windows,doors,and other elements,as shown in it.Exterior walls of a building are dimensioned outside the floor plan.The outermost dimension line is the overall building dimension.The next dimension line,moving toward the plan,indicates wall locations and centerlines to doors and windows.Other minorcel-laneous details in the plan (such as minor offsets,jogs,or cabinetry and fixtures) are located on a third dimension line.This hierarchy of line work allows the carpenters and other trades to quickly locate major framing elements and minor details by referring to the appropriate dimension line.
Designation of Materials:-
Floor plans are generally not used to designate specific materials,as finishes might be too small to show in plan and their selection might be changed later.The amount of material information provided on a floor plan depends on the size and complexity of the proposed construction.The plans for a small residential project may contain more detailed information,such as the finished floor materials,because the design may be simpler and very few materials used,as illustrated in it.
0 Comments