Neal Vogel and Christopher
New York Landmarks Conservancy
Common Bond Winter, 1991
Part 1 of this article, which appeared in the Fall 1990 issue of Common Bond, discussed documenting historic religious buildings with photographs, and offered various tips on appropriate photographic techniques. The following will address measured drawings.
Measured drawings are made by measuring each part of a building and conveying this information in graphic form. Analytical in nature, measured drawings are, in a sense, the reverse of an architect's working drawings. Measured drawings depict a building in its existing state and show not only its "as-built" condition (which often differs markedly from the architect's or builder's original drawings), but also the effects of age and various alterations over time. These drawings also measure and record the numerous quirks that all old buildings exhibit, such as uneven floors and out of plumb walls. Measured drawings have many advantages over photographs. Views of a building that cannot be portrayed by photographs, such as floor plans or sections, or features that are normally hidden from view, such as construction details, can accurately documented in measured drawings. In addition, the dimensions of various building features can be easily determined from measured drawings, making them an invaluable resource for restoration projects, especially if the building is ever badly damaged by fire or another disaster. They are also particularly helpful in obtaining more accurate and consistent bids for repair and restoration work.
Measured drawings are done in orthographic projection; that is, all lines and features are drawn in scale as they actually exist. The principle types of architectural drawings are plans, sections and elevations. A plan is a view looking down through a horizontal slice of a building. A heavy line indicates where the plan slices through the walls and other significant features; features beyond the slice are drawn in lighter lines. A section is a vertical slice through the building. A heavy line indicates where the section bisects the floors, ceilings and other features. An elevation is a view of a vertical surface of a building. Detail drawings are large-scale drawings of particular structural or decorative elements.
Plans, sections and elevations are all essential to include in a documentation project. Plans should be drawn first, starting with a foundation plan, first floor, gallery or loft (when applicable) and finally a roof plan. Sections are the most difficult drawings to execute but are typically the most valuable to have. They not only reveal the overall measurements, but also show the interior dimensions, proportions, finishes and often the wall, roof and floor construction. It is usual for at least two sections to be drawn of a building-one across the longer dimension and one across the shorter. Complex buildings sometimes require more than two sections in order to record the various architectural features. Elevations and detail drawings should follow the plans and sections. Elevations should include each of the building's exterior facades, including those not normally seen by the public. Detail drawings may focus on structural elements, such as the roof construction, or focus on architectural and decorative elements. For documentation purposes, however, complex decorative features can often be more easily and better recorded through photography.
Unlike photography, which can often be done as an "in-house" project, measured drawings require considerably more time than photography. Consequently, few skilled draftspersons can afford to execute a well-prepared set of drawings on a "pro-bono" basis. However, members of the congregation can often help in the process of measuring a building, which usually requires at least three people, thus reducing the cost of the project. It is important for the individual who will actually execute the drawings to be on-site while measurements are being taken to direct the measuring process and to take field notes.
Another cost-saving option for making measured drawings is to use architectural or trade school students. The production of measured drawings can be an excellent summer job opportunity for a student. Since only existing buildings are drawn for documentation projects, advanced design or structural knowledge is not required. Students, in turn, can learn a great deal about historic materials and construction techniques through participation in a documentation project. Often they will produce excellent drawings.
To examine the feasibility of using student interns or summer employees, contact state and private universities in your area that have architectural programs. Trade schools with drafting programs should also be approached. (Trade school students typically develop superior drafting skills, since trade school students are often required to execute highly detailed technical drawings.) Carefully check each applicant's portfolio and qualifications and develop a pay scale based on the cost of living in the area. Often a religious institution can lower costs even further by providing housing for the students, especially if the students hired live outside the immediate area.
Equipment needed to complete a basic set of measured drawings includes: a 25' measuring tape; a 100' tape for overall measurements; a plumb bob to check vertical walls, steeples, etc.; a level to establish horizontal reference (or datum) lines; an oversized clipboard; 11" x 14" graph paper (preferably with 12 squares per inch); a straight edge, such as a draftsman's triangle; soft 2H or H pencils; and, most importantly, an eraser. (As the celebrated 19th century architect H.H. Richardson said, "An eraser is the draftsman's best friend.") Other helpful tools include ladders, flashlights and binoculars.
Another essential piece of equipment for most measuring projects is a profile gauge. A profile gauge is the most accurate tool commonly available to measure a complex molding in place, and it is usually necessary if a set of drawings will include anything beyond a bare outline of ornamental detail. Profile gauges are typically composed of a magnetic handle threaded with short, stiff wire rods. When a profile gauge is placed against a molding, the wire rods reproduce the profile of the molding. This shape is then traced from the profile gauge onto a sheet of paper and later incorporated (at a reduced scale) into the final drawings.
More sophisticated measuring equipment is available, such as electronic measuring devices and optical plumb bobs. Civil surveying equipment can also be extremely useful in establishing accurate reference points. X- ray techniques c also be helpful, when necessary, to examine hidden structural conditions, such as the interior of wall cavities. However, this is very expensive and should only be utilized when the condition of the building warrants the cost.
Approaching a large church or synagogue on the first day of measuring armed only with measuring tape, pencil and blank piece of graph paper can be intimidating, even for an experienced professional. It is important not to get muddled with excessive detail at the beginning of the project, and to focus on "the big picture." Using the grid paper, establish a rough scale for the field drawings. Establish reference points to measure from and think of the building in terms of vertical and horizontal planes. For example, a water table, if level, may be a good reference line for vertical measurements. Approach the building in a systematic way. Start measuring from the left corner of the front facade (while facing the building) and work counter-clockwise around the building. Using this technique, all the measurements for the field notes and final drawings will be read from left to right.
When measuring, take cumulative or "running" measurements. Hold the measuring tape at one corner or "datum point" and read all desired points along that line without moving the tape, rather than continually moving the tape and taking each measurement from the last reading.
This prevents the accumulation of small errors and makes any measuring errors quickly apparent. As a way of verifying the accuracy of the exterior measurements, make checks from the interior once the wall thickness is determined. After the building's main dimensions are established, go back for detailed measurements of typical features, such as windows, columns and pinnacles.
Don't assume that rooms or buildings are square, walls are plumb, or floors are level. Take diagonal measurements and check walls and floors to determine distortion early in the documentation project.
Establish datum lines and planes as reference points.
Cumulative measurements are more accurate than consecutive measurements because they use a common zero point and thus do not require the tape to be relocated after each measurement.
Hold the tape taut when making measurements. Temperatures, tension and wind can affect the accuracy of tape measurements by causing the tape to stretch, shrink or sag.
Know where the zero point is on the tape. It is not always at the end.
Horizontal distances must be measured with the tape held level. Use a plumb line to measure points displaced vertically.
Access to roofs, vaulted ceilings, steeples and crawl space is often a major difficulty. However, it is vitally important that these areas are measured. Vital information, such as the thickness of the wall, the structure of the ceiling, and the pitch of the roof and its structural framing, can often only be determined by taking measurements in attics or crawl spaces.
The process of measuring a building can be simplified if a construction project is in progress. Scaffolding and cherry pickers allow access to otherwise hard to reach parts of the building. If the walls need to be opened up in order to replace mechanical systems or investigate structural problems, use the opportunity to examine and measure the internal construction of the wall.
The drawings should first be traced in pencil on vellum and reviewed by someone experienced with documentation projects. Final drawings should be traced in ink on Mylar.