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climates

Very Cold - A very cold climate is defined as a region with approximately 9,000 heating degree days or greater (65°F basis) or greater and less than 12,600 heating degree days (65°F basis).

Cold - A cold climate is defined as a region with approximately 5,400 heating degree days (65°F basis) or greater and less than approximately 9,000 heating degree days (65°F basis).

Mixed-Humid - A mixed-humid and warm-humid climate is defined as a region that receives more than 20 inches of annual precipitation with approximately 4,500 cooling degree days (50°F basis) or greater and less than approximately 6,300 cooling degree days (50°F basis) and less than approximately 5,400 heating degree days (65°F basis) and where the average monthly outdoor temperature drops below 45°F during the winter months.

Hot-Humid - A hot-humid climate is defined as a region that receives more than 20 inches of annual precipitation with approximately 6,300 cooling degree days (50°F basis) or greater and where the monthly average outdoor temperature remains above 45°F throughout the year. This definition characterizes a region that is similar to the ASHRAE definition of hot-humid climates where one or both of the following occur:

  • a 67°F r higher wet bulb temperature for 3,000 or more hours during the warmest six consecutive months of the year; or
  • a 73°F or higher wet bulb temperature for 1,500 or more hours during the warmest six consecutive months of the year.

Hot-Dry/Mixed-Dry - A hot-dry climate is defined as region that receives less than 20 inches of annual precipitation with approximately 6,300 cooling degree days (50°F basis)or greater and where the monthly average outdoor temperature remains above 45°F throughout the year.

A warm-dry and mixed-dry climate is defined as a region that receives less than 20 inches of annual precipitation with approximately 4,500 cooling degree days (50°F basis) or greater and less than approximately 6,300 cooling degree days (50°F basis) and less than approximately 5,400 heating degree days (65°F basis) and where the average monthly outdoor temperature drops below 45°F during the winter months.

Marine - A marine climate meets is defined as a region where all of the following occur:

  • a mean temperature of the coldest month between 27°F and 65°F;
  • a mean temperature of the warmest month below 72°F;
  • at least four months with mean temperatures over 50°F; and
  • a dry season in the summer, the month with the heaviest precipitation in the cold season has at least three times as much precipitation as the month with the least precipitation.

information

Building Science Insights are short discussions on a particular topic of general interest. They are intended to highlight one or more building science principles. The discussion is informal and sometimes irreverent but never irrelevant.

Building Science Digests provide building professionals from different disciplinary backgrounds with concise overview of important building science topics. Digests explain the theory behind each topic and then translate this theory into practical information.

Published Articles aare a selected set of articles written by BSC personnel and published in professional and trade magazines that address building science topics. For example, our work has appeared in Fine Homebuilding, Home Energy, ASHRAE's High Performance Buildings, The Journal of Building Enclosure Design and The Journal of Building Physics. We thank these publications for their gracious permission to republish.

Conference Papers are peer-reviewed papers published in conference proceedings.

Research Reports are technical reports written for researchers but accessible to design professionals and builders. These reports typically provide an in-depth study of a particular topic or describe the results of a research project. They are often peer reviewed and also provide support for advice given in our Building Science Digests.

Building America Reports are technical reports funded by the U.S. Department of Energy (DOE) Building America research program.

Designs That Work are residential Case Studies and House Plans developed by BSC to be appropriate for residential construction in specific climate zones. Case Studies provide a summary of results for homes built in partnership with BSC’s Building America team. The case study typically includes enclosure and mechanical details, testing performed, builder profile, and unique project highlights. House Plans are fully integrated construction drawing sets that include floor plans, framing plans and wall framing elevations, exterior elevations, building and wall sections, and mechanical and electrical plans.

Enclosures That Work are Building Profiles and High R-Value Assemblies developed by BSC to be appropriate for residential construction in specific climate zones. Building Profiles are residential building cross sections that include enclosure and mechanical design recommendations. Most profiles also include field expertise notes, material compatibility analysis, and climate challenges. High R-Value Assemblies are summaries of the results of BSC's ongoing High R-Value Enclosure research — a study that BSC has undertaken for the U.S. Department of Energy (DOE) Building America research program to identify and evaluate residential assemblies that cost-effectively provide 50 percent improvement in thermal resistance.

Guides and Manuals are "how-to" documents, giving advice and instructions on specific building techniques and methods. Longer guides and manuals include background information to help facilitate a strong understanding of the building science behind the hands-on advice. This section also contains two quick, easy-to-read series. The IRC FAQ series answers common questions about the building science approach to specific building tasks (for example, insulating a basement). The READ THIS: Before... series offers guidelines and recommendations for everyday situations such as moving into a new home or deciding to renovate.

Information Sheets are short, descriptive overviews of basic building science topics and are useful both as an introduction to building science and as a handy reference that can be easily printed for use in the field, in a design meeting, or at the building permit counter. Through illustrations, photographs, and straightforward explanations, each Information Sheet covers the essential aspects of a single topic. Common, avoidable mistakes are also examined in the What's Wrong with this Project? and What's Wrong with this Practice? mini-series.

Research Reports
Joseph Lstiburek, Terry Brennan, Nathan Yost

This article briefly repeats some of the information in the other mold articles but also includes information on how to prevent mold in residential structures. Mold requires water. No water, no mold. Mold is the result of a water problem. Fix the water problem, clean up the mold and you have fixed the mold problem. For more information, see Popular Topics/Homeowner Resources.

Research Reports
Joseph Lstiburek

Builders for many years have put mechanical equipment and ducts in non-living spaces such as crawlspaces and attics primarily to save valuable floor space. Be that as it may (there are lots of good reasons for having this equipment in conditioned spaces, GIVEN proper attention to ventilation and pressurization issues), it makes perfect sense to condition these areas, for a variety of energy, moisture and durability reasons.

Published Articles
Joseph Lstiburek

Top ten blunders that rot your house, waste your money, and make you sick. Reprinted with permission from Fine Homebuilding Magazine, April/May 2004, pages 52-56. 

Information Sheets
Crawlspaces should be designed and constructed as mini-basements.  Crawlspaces should not be vented to the exterior (see FAQ on Crawlspace Venting). They should have their floors uninsulated, the...
Information Sheets
Water managed foundation systems prevent the build-up of water against foundation walls, thereby eliminating hydrostatic pressure. No pressure, no force to push water through a hole. Groundwater...
Information Sheets
Joseph Lstiburek
Joseph Lstiburek's classic list of building practices not recommended for hot-humid climates. This list was first posted on Building Science Corporation's website in 1997.10. Vented Attics and...
Guides and Manuals
Betsy Pettit, Ken Neuhauser, Cathy Gates
The purpose of this guide is to provide useful examples of high performance retrofit techniques for the building enclosure of wood frame residential construction in a cold and somewhat wet climate....
Cold
Guides and Manuals
Joseph Lstiburek
This pamphlet is designed for members of the residential construction and remodeling industries, as well as owners and managers who work in affordable housing. It presents building guidance for both...
Building Science InsightsNewsletters
Joseph Lstiburek
I remember sitting around listening to stories my dad and his friends would tell when they were hanging around in the basement playing cards. They would laugh uproariously, tease each other, get...
Building Science InsightsNewsletters
Joseph Lstiburek
Imagine a three-dimensional molecular billiard game with billiard balls that are sometimes sticky, and where the rules depend on where you are on the table. Then assume that there are many different...
Building Science Insights
Joseph Lstiburek
It’s pretty easy to deal with new basements. They are not hard to insulate. The majority of them do not leak or smell and the buildings on top of them are generally not rotting.1 If you want a...
Building Science Insights
Joseph Lstiburek
Mold is pretty easy to understand.  No water no mold.  Any questions?  Well, there are a few.  For one we have more mold today, but we don’t have more water.  What’s with that?  We’ve always built...
Building Science Insights
Joseph Lstiburek
Crawlspaces stink, they rot, and are just plain icky. Photograph 1 shows the modern crawlspace, which is a forest of water droplets on the underside of fiberglass batt insulation. The exposed wood...
Mixed-HumidHot-Humid
Building Science Digests
Joseph Lstiburek

We learn our lessons from disaster. Hurricane Andrew taught us about wind. Hurricanes Charley, Frances and Jeanne taught us about rain. The Red River of the North Basin taught us about floods. Hurricane Katrina had it all: wind, rain and flood. That we will rebuild, and rebuild in the same place, is not in doubt. This is what we do – for better or worse. If we are to rebuild and if we are to rebuild in the same place how should we rebuild?

Mixed-HumidMarineHot-Humid
Building Science Digests
Joseph Lstiburek

Moisture accumulates when the rate of moisture entry into an assembly exceeds the rate of moisture removal. When moisture accumulation exceeds the ability of the assembly materials to store the moisture without significantly degrading performance or long-term service life, moisture problems result.

Building America Reports
Kohta Ueno, Joseph Lstiburek

Basements can account for up to one quarter of the typical energy consumption in a house. Therefore, insulating foundations is a critical measure for achieving high performance buildings. However, many foundations are damp (either due to bulk water or capillary “wicking” of moisture) or of a type of construction that is not easy or straightforward to insulate (such as rubble foundations). Damp foundation repair methods can be “leveraged” to provide energy efficiency benefits. An example of this “hybrid” approach is spray foam insulation, which can be an effective means of liquid phase water control (leaking basement), vapor phase water control (diffusion and air leakage transported condensation) as well as an effective insulation.

Building America Reports
Kohta Ueno, Joseph Lstiburek

Successfully executing strategies to control bulk water for foundations is critical for building durability, indoor air quality, and creating acceptable conditions and/or living spaces within the foundation space. Although the energy impacts of properly done bulk water control are small to insignificant, it should be considered a base requirement for any high performance house. In addition, measures such as basement insulation are predicated on properly managed foundation bulk water.

Building America Reports
John Straube

The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. Many concerns, including the rising cost of energy, climate change concerns, and demands for increased comfort, have led to the desire for increased insulation levels in many new and existing buildings. Building codes and green building codes are being changed to require higher levels of thermal insulation both for residential and commercial construction. This report will review, and summarize the current state of understanding and research into enclosures with higher thermal resistance, so-called “High-R Enclosures.” Recommendations are provided for further research. For more information see Popular Topics/Foundations and Slabs and Popular Topics/High R-Value Walls.

Building America Reports
Joseph Lstiburek

Conditioned crawlspaces perform better than vented crawlspaces in terms of safety, health, comfort, durability and energy consumption. Conditioned crawlspaces also do not cost more to construct than vented crawlspaces. Despite that, there is not a significant trend towards the construction of conditioned crawlspaces. The model codes do not allow the construction of “unvented” crawlspaces – except in very limited circumstances, but they do allow the construction of “conditioned” crawlspaces. The distinction is important and necessary. Four conditioned crawlspaces were constructed and monitored over a 12-month period. The data is presented and used to support the current code requirements for the construction of conditioned crawlspaces.