Architectural Detailing

Function, Constructibility, Aesthetics

Edward Allen, Patrick Rand

• Publisher: Wiley
• Year: 2016
• ISBN:
  9781118882504
• Edition: 3
• Topic: Architecture
• Subtopic: Architecture Design

The industry-standard guide to designing well-performing buildings

Architectural Detailing systematically describes the principles by which good architectural details are designed. Principles are explained in brief, and backed by extensive illustrations that show you how to design details that will not leak water or air, will control the flow of heat and water vapor, will adjust to all kinds of movement, and will be easy to construct. This new third edition has been updated to conform to International Building Code 2012, and incorporates current knowledge about new material and construction technology. Sustainable design issues are integrated where relevant, and the discussion includes reviews of recent built works that extract underlying principles that can be the basis for new patterns or the alteration and addition to existing patterns. Regulatory topics are primarily focused on the US, but touch on other jurisdictions and geographic settings to give you a well-rounded perspective of the art and science of architectural detailing.

In guiding a design from idea to reality, architects design a set of details that show how a structure will be put together. Good details are correct, complete, and provide accurate information to a wide variety of users. By demonstrating the use of detail patterns, this book teaches you how to design a building that will perform as well as you intend.

• Integrate appropriate detailing into your designs
• Learn the latest in materials, assemblies, and construction methods
• Incorporate sustainable design principles and current building codes
• Design buildings that perform well, age gracefully, and look great

Architects understand that aesthetics are only a small fraction of good design, and that stability and functionality require a deep understanding of how things come together. Architectural Detailing helps you bring it all together with a well fleshed-out design that communicates accurately at all levels of the construction process.

PART I
DETAIL PATTERNS

SECTION 1
FUNCTION

For a building to function well, its details must function well. When designing details for a building, the detailer has countless choices to make and no prescribed path toward the best solution. This portion of the book guides the detailer along this path by describing factors that affect the functional performance of details.

In architecture, function certainly includes the technical performance of the details that contribute to making a building safe and secure for its occupants. But function also includes features that affect the qualities of the forms, surfaces, and spaces that compose the building. A space that is firm and dry but that has an aggravating echo or glaring light does not function as well as it could.

The detailer is challenged to address the function needs of the building when it is new, but also long into the future and sometimes beyond the lifetime of those who designed or constructed it. Buildings constantly change in response to natural forces, such as the daily cycles of temperature and light, as well as in response to seasonal changes. A basic grasp of physics and of biological and chemical processes is part of the detailing process. Other functions concern the people who engage with the building every day, altering it internally and externally through countless actions.

The detail patterns that relate to function address the breadth of these topics. They are organized into thematic groups to focus the detailer's attention on each topic individually. Each pattern builds awareness of the issue and includes directions toward possible solutions. The patterns describe the natural processes involved, as well as the codes, standards, and conventional practices that are relevant to discovering appropriate detailing solutions.

CHAPTER 1
Controlling Water

INTRODUCTION

Water must be controlled in order to prevent leakage, which is the penetration of water through a building assembly. For water to penetrate through a building assembly, three conditions must all occur at the same time:

1. There must be an opening through the assembly.
2. There must be water present at the opening.
3. There must be a force to move the water through the opening.

If any one of these three conditions is not met, water will not penetrate the assembly. In designing any exterior detail, therefore, we can pursue one or more of three strategies:

1. We can try to eliminate openings in building assemblies.
2. We can try to keep water away from openings in building assemblies.
3. We can try to neutralize forces that move water through openings in building assemblies.

Complete success in any one of these three strategies will result in the complete elimination of water leaks, but sometimes in detailing we pursue two of these strategies or even all three of them at the same time. This approach gives added security in case one of the strategies fails as a result of poor workmanship or building deterioration. Let us consider each of these strategies briefly and list the detail patterns that relate to each. All of the patterns listed will be further explained later in this chapter.

1. Eliminating openings in building assemblies

Every building is full of openings. A shingled roof has an opening under each shingle. A wall has cracks around windows and doors, and around joints between the units of material from which the wall is made. Additional cracks and holes may form as the building ages and deteriorates. We can attempt to eliminate all these openings by using preformed gaskets and sealants. As the sole strategy, this is unreliable, however. Gaskets may not seal securely if they are the wrong size or resiliency, or if the surfaces they touch are rough or unclean. Sealants may fail to adhere properly if the materials to which they are applied are not scrupulously clean and properly primed, or if the installer does not compress the sealant fully into the seam. Both sealants and gaskets can deteriorate from weathering and from the flexing and stretching they may undergo as the building ages. A building skin that relies on sealants and gaskets alone for watertightness will leak sooner or later. Furthermore, even a small defect in a sealant or gasket that is exposed to the weather can leak very large amounts of water, just as a small hole in a bathtub can create a very large puddle.

Sealants and preformed gaskets are extremely useful, however, as components of an overall strategy for making a building skin watertight. Therefore, it is important to know how to detail sealant joints and gasket joints correctly and how to incorporate them into more complex schemes for controlling water penetration. The detail pattern that relates to eliminating openings in building assemblies is:

• Sealant Joints and Gaskets (p. 36)

2. Keeping water away from openings in building assemblies

There are a number of effective ways to keep water away from openings. Often it is useful to keep most water away from an opening simply to reduce the volume of water that must be dealt with at the opening itself. In many cases we can easily and securely keep all water away from an opening.

The detail patterns that relate to keeping water away from openings in building assemblies are the following:

• Wash (p. 7)
• Overlap (p. 12)
• Overhang and Drip (p. 15)
• Drain and Weep (p. 19)
• Ventilated Cold Roof (p. 22)
• Foundation Drainage (p. 24)

3. Neutralizing forces that move water through openings in building assemblies

There are five forces that can move water through an opening in a wall or a roof: (1) gravity, (2) surface tension, (3) capillary action, (4) momentum, and (5) a...