Essential Building Science

Understanding Energy and Moisture in High Performance House Design

Jacob Deva Racusin

• Publisher: New Society Publishers
• Year: 2016
• eBook ISBN: 9781550926293
• Topic: Architecture
• Subtopic: Sustainability in Architecture

Down and dirty – a complete step-by-step guide to making, installing and living with beautiful, all-natural earthen floors

Poor heat and moisture management are the enemies of durable, comfortable, and efficient housing, and good building design and construction starts with a solid understanding of good building science.

Essential Building Science provides a highly visual and accessible introduction to the fundamentals of building science for residential construction.

Part one covers the rationale behind high-performance design and the fundamentals of building physics, including thermal dynamics, moisture transfer, and hygro-thermal dynamics such as vapor drive and condensation.

Part two teaches the vital critical thinking skills needed to consider buildings as whole systems and to develop thermal and moisture control strategies regardless of the specifics of the design. Case studies and examples from across North American climatic zones illuminate real-life problems and offer builders, designers, and DIYers the insights and tools required for creating better new buildings and dramatically improving old ones.

Good science plus critical thinking equals high performance buildings.

Chapter 1

Establishing Goals

BEFORE WE DIVE INTO THE THEORY, strategies, and details of how to manage heat and moisture in our buildings, it is critical that we begin by establishing the values and goals for our building projects, knowing that every project, with different stakeholders and serving specific purposes, will have a unique composition of values and goals. Why is this so important? After all, the physics are the same; heat and moisture don’t change based on your proclivities. The importance lies in being able to ensure that the many decisions you will have to make in response to the guidelines presented in this book all lead toward a result that matches your original intentions. This is not something unique to building science — this is an important approach for any project. It is all too easy to think that there is a “right way” from a building science perspective, that just needs to be identified. Rather, the information concerning the performance of our buildings can be used in support of our goals — or it can lead us away from them if we haven’t done a good job of setting clear objectives.

Fig. 1.1

There are many definitions and graphical flowcharts representing this process. Here is a simple structure that runs through the exercise with a few basic examples:

Identify Values

First, what values motivate this project and what are your priorities? It is very important to note that you will have values that will conflict with each other; you will have to assign a hierarchy of importance to them. The more time you can spend getting clear about your priorities (and practicing how to communicate them clearly to others), the easier it will be to make decisions to resolve inherent conflicts — many of which inevitably involve cost — when they surface.

Define Goals

Next, what are the specific goals and results you are working toward? The goals should reflect your values. Set these goals early in the design process to guide the strategies and details.

Table 1.1

Value: Health and Safety
Goal: Good indoor air quality
Strategies	Actions
Keep building dry (avoid mold)	Follow moisture control strategies to create a well-detailed enclosure that avoids leaks, condensation, and groundwater intrusion.
Good ventilation	Install a well-sized and appropriately designed ventilation system for the home, and ensure it runs correctly.
Reduce pollutants	Avoid products with off-gassing chemicals such as the solvents and glues common in paints, floor covering, and furnishings.
Combustion safety	Avoid the use of combustion appliances and/or use sealed combustion appliances when necessary.
Goal: Safe Use for All
Universal Design (UD)	Follow established UD guidelines to ensure access to those needing assistance moving about in the home.

Table 1.2

Value: Comfort
Goal: Stable indoor temperature
Strategies	Actions
Control heat transfer	Follow thermal control strategies for a well-detailed, airtight and well-insulated enclosure, and include thermal mass inside the building.
Provide appropriate heating and cooling	Install a well-sized and appropriately designed heating/AC system for the home, and ensure it runs correctly and is serviceable.
Keep surface temperatures warm	Insulate slabs, walls, and ceilings. Install thermally efficient windows.
Goal: Controlled air flow (no drafts when cold, circulation when warm)
Install quality air barrier	Ensure air barrier detailing in design, and perform quality control in the field with a blower-door test.
Good ventilation	Install a well-sized and appropriately designed ventilation system for the home, and ensure it runs correctly.
Goal: Controlled humidity levels
Same as for other goals addressing comfort	Keep building dry, keep surfaces warm, install an appropriate ventilation system.

Setting measurable targets will make it easier to identify strategies and understand the results. Examples might include wanting a net zero energy home, or avoiding the use of any of the materials on the “Living Building Challenge Red List.”

Develop Strategies

How can you reach your goals? You will need to decide on the steps and solutions that are likely to give you the results you seek. The strategies laid out in this book that support good moisture and thermal control may be valid unto themselves, but depending on the other goals you have set for this building, some of these strategies will be highly relevant, and others less so.

This is a deeply personal exercise, whether for owners or for professionals. The more intention you can bring to this process, the more likely it is that the final project will reflect your values, reach your goals, and employ successful strategies. In the world of high-performance building, common priorities emerge; some of these appear in the list below...

Table of contents

• Cover
• Title Page
• Copyright Page
• ACKNOWLEDGMENTS
• INTRODUCTION
• Part I: Rationale
• Part II: Fundamentals of Building Physics
• Part III: Developing Strategies
• ENDNOTES
• RESOURCES
• INDEX
• ABOUT THE AUTHOR
• A NOTE ABOUT THE PUBLISHER