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Shedding The "Pencil And Paper" Mentality;
Part 8 "Efficient" Drawings
By Thomas E. Irvin, CCS, CSI, Architect In Private Practice
© 2002, tei Architect, Specifications Consultant, teiarch@chorus.net

In the article, P & P Part 6 "How To Get Started" I suggested choosing a self-taught path for learning CADD versus taking a formal training course. The rationale for this was that most people retain more knowledge about software if they’re doing real work instead of wading through generic classroom examples. Besides learning how to use the software, you should learn how to be an efficient CADD user as well.

When you save a CADD drawing, you create a drawing file that’s stored on a floppy disk, a hard disk (fixed or removable) or a compact disk. As you add develop the project, the drawing file gets bigger and bigger. Drawing file sizes of large projects and/or those containing 3 dimensional elements can eventually become so large they can become almost unmanageable. This wasn’t a concern in the pencil and paper days but with to electronic storage media, it is. As you develop your CADD drawings, remember to keep file size in mind.

While producing your latest masterpiece, think about efficiency in terms of file size. Very large file sizes are often necessary but thinking efficiency means that they don’t have to be any larger than necessary to contain the information for the drawing. Some will say: "Why bother? Don’t I have enough to worry about just getting a drawing done in CADD?" Well, sure you do, but once you start using CADD, you also have to be aware of some of the issues that accompany it.

Why is drawing file size important? Given two building projects of the same size and complexity, the drawing files for one building can be several times larger than the other, depending on how well the CADD user understands what is going on. Everything else being equal, the project with the larger file sizes is not as efficient as the one with smaller file sizes.

Large file sizes take longer to open up, regardless of the computer’s processor speed, random access memory (RAM) and hard disk access time. In extreme cases, the time spent waiting while a larger-than-it-needs-to-be drawing file "loads" could be spent working on the drawing itself.

Large files take longer to save and require more space on your hard disk. A few years ago, large capacity hard drives were extremely expensive. While this is no longer true, the fact that huge, inexpensive hard drives are available is no excuse for keeping drawing file sizes as small as possible.

Larger than necessary files take longer to plot. A plotter must sort through an entire drawing file to determine what’s to be plotted and what’s garbage. Unnecessarily large drawing files can significantly slow down plotters and increase plotting times!

STOP MAKING MISTAKES WHEN SPECIFYING
PORTLAND CEMENT PLASTER (STUCCO)
By Walt Pruter, CSI, Member Emeritus

Confusing and often contradictory, specifications for lath and Portland cement plaster work have resulted in job delays, unforeseen extra charges and compromised construction on many projects. What caused the ambiguity in the specs, which are intended to supplement and clarify the intent of the architectural drawings -laziness, lack of knowledge, unrealistic headlines or inadequate compensation, all or individually, have been ascribed as the cause of poor specifications.

REFERENCING OUTDATED STANDARDS

The new model INTERNATIONAL BUILDING CODE and INTERNATIONAL RESIDENTIAL CODE are reference codes in that they use published standards such as ASTM to describe materials and how they should be installed. This is contrary to the UNIFORM BUILDING CODE and CALIFORNIA BUILDING CODE, which prescribe how work is to be done. They might also be called performance codes.

ASTM Standards for materials often are changed every year. Because they are so current, they have replaced many Federal Specifications and American National Standards Institute (ANSI), specifications, which although out of print for over twenty years, are still referenced.

For example:

ANSI A 42. 1, Standard Specification for Application of Interior Gypsiin7 Plaster, was replaced in 1976 by ASTM C 842.

ANSI A 42.2, Portland Cement and Portland Cement-Lime Plastering Exterior (Stucco) and Interior, was replaced in 1976 by ASTM C 926

ANSI A 42.3, Lathing and Furring.for Portland Cement and Portland Cement-Lime Plaster Exterior (Stucco) and Interior, was replaced by ASTM C 1063 in 1976.

ANSI A 42.4, Standard Specification, Installation of interior Lathing and Furring was replaced by ASTM C 841.

These are all standard installation specifications and should be referenced in every job specification requiring more than building code compliant minimum standards. There are also ASTM product specifications to differentiate between products intended for the source use such as expanded metal and wire fabric types of plaster reinforcement. ASTM C 847 is for expanded metal lath; ASTM C 933 for welded wire lath and ASTM C 1032 is for woven wire plaster base. The specification writer would be advised to further call out brand names of products reputed to be of superior quality, providing they are available in the local market. Too many specifications list brand names of products and materials no longer manufactured or not available in the region where the project is located.

UNDERSTANDING LATH AND PLASTER CONSTRUCTION

Although building codes and supporting fire tests do not require that the weather-resistive barrier be fire resistant or flame resistant, specifications often contain a requirement for this material. The Kraft paper, weather resistive barrier has nothing to do with the fire rating of a wall construction. Drawings often show details that are contradicted by specification requirements. An example of this would be where a detail of asuspended ceiling grillage shows the main channels supported by hangers to be installed within six (6) inches of abutting construction and the lath on the ceiling terminated with a casing bead. This is good unrestrained construction! The specifications; however, may include instructions to install CORNERITE in the re-entrant angle, which would negate the efficacy of the unrestrained detail.

We frequently see plaster specifications listing lime as a required constituent for the Portland cement plaster then plastic cement for the cement. Building codes are specific in stating that lime or any other plasticizing agent cannot be used with plastic Portland cement (ASTM C 1328) because plasticizers are introduced in the manufacturing plant.

Some spec writers insist on including water-repellent admixes that they specify for concrete to also be added to the plaster mix. This is in spite of the Portland Cement Association's caution that, "Laboratory tests that measure time of setting and water permeability of plaster show that water-repellent compounds may actually retard Portland cement hydration and increase permeability."

Some specification writers don't understand the difference between "moist curing" and "air drying." As a result many cement plaster installations end up insufficiently hydrated. We even see requirements for gypsum plaster to be moist cured, which is totally wrong.

IRRELEVANT ITEMS

The office master specification developed by an architectural firm usually contains all the requirements for different plasters to be applied in a variety of ways. This means that the master spec will have requirements for plastering on lath over open framing, plastering over lath with sheathing on the framing, plastering on masonry and monolithic concrete, suspended ceilings and many other conditions.

A particular job specification; however, must be specific to the job at hand and contain only those requirements necessary for the project. This would require that a master spec be revised to eliminate items and requirements not applicable to the job in question. This requires time and effort, and too many architects find it easier to use the office master spec on every job. They assume that this will assure that there will be no overlooked omissions that the architect wants to avoid so that the contractor cannot request a change order extra to provide something that was not included in the contract documents.

Inclusion of irrelevant items is not only undesirable but also costly. Even though a specification requirement cannot be located on the plans, the contractor has to provide an allowance in his bid assuming that it is there somewhere and will be required. This results in over-priced bids and obfuscates the true job requirements.

These are only a few of the "boo bo os" that come to mind. A specification writer can have their specs reviewed and critiqued by unbiased technical representatives affiliated with the local wall and ceiling trade association. In Southern California that would be the TECHNICAL SERVICES & INFORMATION BUREAU in Fullerton (Phone- 714/256-1708) and in Northern California the LATH & PLASTER INSTITUTE OF NORTHERN CALIFORNIA (Phone: 925/283-5160).

This article was prepared by Walt Pruter, a Consultant to the TECHNICAL SERVICES& INFORMATION BUREAU and Member Emeritus of CSI. Walt is a long time member of the Orange County and Los Angeles CSI Chapters. Walt's e-mail is: wf.pruter@gte.net