mold

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Two Rules for Humidity

To prevent moisture damage from humid air, just do these two things

Posted on Nov 29 2017 by Allison A. Bailes III, PhD
prime

Because I've written so much about moisture in buildings, I get a lot of questions on the topic. Some are about walls. Some are about the attic. Some are about windows. Some are about the crawl space (which generates the most questions on this topic).

The key to answering a lot of those questions boils down to an understanding of how water vapor interacts with materials. Once you know that, it's easy to see the two rules for preventing damage from humidity.


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Image Credits:

  1. Andy Bell
  2. Energy Vanguard

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There’s Mold in My Attic

After converting a seasonal cabin to a year-round use, a homeowner discovers a problem

Posted on Nov 27 2017 by Scott Gibson

A three-season cabin built in the 1940s became a year-round dwelling two years ago, but owner Marty Pfeif has discovered an alarming problem: a bumper crop of mold in the attic.

In a post at the Q&A forum, Pfeif ticks off the particulars, including no apparent attempts at air-sealing, "shake and rake" R-19 insulation on the attic floor and some batting against the walls, no vapor barrier, and a ridge vent but no gable vents.


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Image Credits:

  1. Marty Pfeif

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An Interesting Moisture Problem in a Trendy Restaurant

Observations by astute diners give clues as to the source

Posted on Sep 6 2017 by Allison A. Bailes III, PhD
prime

I've got the curse, you know. I can't walk into a building and not check out what's going on with ductwork, windows, and anything else that lets me apply what I know about building science.

Recently, I went to lunch at a trendy restaurant near Emory University and of course looked up at the ceiling. You can see what caught my attention in photo at right. The restaurant is only three or four years old, so I've been watching this problem get worse for a while now.

I have a few ideas about what's happening here. Do you?


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Image Credits:

  1. All photos: Energy Vanguard

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Pete’s Puzzle: Mold on Painted Clapboards is Food for Thought

There is mold on the factory-primed, latex top-coated wood clapboards on the south but not the north side of our house

Posted on Jul 20 2017 by Peter Yost

Whenever my wife starts a conversation with, “OK, Mr. Building Scientist,” I know I am in some kind of trouble. That proved to be the case one day when we were out hanging laundry on the south side of our house.


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Image Credits:

  1. All photos: Peter Yost

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Pete’s Puzzle: Mold in Certain Closets

After putting up with mold for a long time, a homeowner finally bites the bullet and hires a moisture management expert

Posted on Dec 22 2016 by Peter Yost

Author’s Note: I am setting up a series of building investigations that I have done over the years as puzzles, presenting successive pieces as an interesting way to tell the story. As with any story, you can read the end first if you want, but that approach cuts down on the drama (admittedly not a bad thing for some folks…)


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Image Credits:

  1. Most photos by Peter Yost — Photo #2 by Frank Steiner — Photo #7 by Rich Misner

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Do Humidifiers Create IAQ Problems?

Adding water vapor to your indoor air may do more than you think

Posted on Nov 16 2016 by Allison A. Bailes III, PhD
prime

It's that time of year when heating systems start coming out of their summer hibernation. (Except maybe in Vermont. Michael Blasnik's Nest data showed that Vermonters are about the last to start heating their homes in the fall.) Then everyone starts looking for their lotion and lip balm. Gaps appear in hardwood flooring as it dries out. Buildings begin to creak and pop. And then the humidifiers come out.

Yes, humidifiers can help with low indoor humidity. But what effect might they have on indoor air quality?


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Image Credits:

  1. Images #1 and #3: Energy Vanguard
  2. Image #2: Adapted from "Criteria for Human Exposure to Humidity in Occupied Buildings," Dr. Elia Sterling, 1985

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Building Science Puzzles: The Jigsaw Approach

Tracking down performance problems is all about getting the building science right — and following the rules of jigsaw puzzles

Posted on Oct 20 2016 by Peter Yost

Just about every week, I get a call or an email that turns into a building science puzzle. While the problems are varied, how you solve them doesn’t change.

First, you understand how heat and moisture move through building assemblies. Second, you follow the advice of your spouse.

My wife of 27 years is a real master at jigsaw puzzles, and she would laugh to learn that I think of myself as a puzzle master of any sort, since I am useless at the jigsaw ones. But she completely agrees that I should use her method of solving jigsaw puzzles in my work on building science problems.


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Image Credits:

  1. Images #1 and #2: Peter Yost

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Indoor Microbes and Human Health

How do the bacteria and fungi living in our homes affect our health?

Posted on Sep 16 2016 by Martin Holladay
prime

The word “health” is usually reserved for living things. Our children can be healthy or unhealthy, and so can our pets and the apple trees in the back yard. But what’s a “healthy house”?

Most people use the phrase “healthy house” to describe a house that either promotes the health of the occupants or, at a minimum, doesn’t make the occupants sick. Of course, everybody wants a healthy house: Who wants to live in a house that makes you sick?


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Image Credits:

  1. Craig Haas / www.markshomeinspection.com

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Being a Carpenter Isn’t Simple Anymore

A self-described ‘forensic carpenter’ encounters shoddy construction practices in Colorado

Posted on Sep 2 2016 by Martin Holladay
prime

After working for years as a carpenter, Bart Laemmel, a resident of Crested Butte, Colorado, decided to upgrade his skills. “I have a thirst for knowledge,” he said. Speaking at a presentation at the recent Westford Symposium on Building Science, Laemmel deployed his self-deprecating humor. “I am a HERSIndex or scoring system for energy efficiency established by the Residential Energy Services Network (RESNET) that compares a given home to a Home Energy Rating System (HERS) Reference Home based on the 2006 International Energy Conservation Code. A home matching the reference home has a HERS Index of 100. The lower a home’s HERS Index, the more energy efficient it is. A typical existing home has a HERS Index of 130; a net zero energy home has a HERS Index of 0. Older versions of the HERS index were based on a scale that was largely just the opposite in structure--a HERS rating of 100 represented a net zero energy home, while the reference home had a score of 80. There are issues that complicate converting old to new or new to old scores, but the basic formula is: New HERS index = (100 - Old HERS score) * 5. rater,” he said. “It was an intense training — seven days straight. I figured I knew everything. And I am a LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. professional. I know how to check stuff off.”


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Image Credits:

  1. All photos: Bart Laemmel

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Preventing Water Entry Into a Home

To lower your home’s indoor relative humidity, you need to address all sources of water entry

Posted on Jan 15 2016 by Martin Holladay
prime

If it is designed well, the thermal envelope of your home should control the flow of heat, air, and moisture. Unfortunately, the floors, walls, and ceilings of older buildings are often leaky: they leak heat, they leak air, and they leak moisture.

If you are building a new house, you have the opportunity to control the flow of heat, air, and moisture through your home’s building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials.. The result will be a durable, comfortable building that doesn’t cost much to heat and cool.


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Image Credits:

  1. Martin Holladay

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