Air Date: 1-11-2019|Episode 529
Henry spent 11 years working on this over 500 page masterpiece and created a truly remarkable book. Order your copy and learn all the science behind better buildings. Buildings Don’t Lie includes all the science behind creating better buildings and houses.
Buildings Don’t Lie
Henry Gifford is a building scientist with 25+years of experience fixing problems in buildings and making them more energy efficient. He spent 11 years working on a remarkable book about the science behind creating better buildings.
I can’t improve on Popular Mechanics editors’ review of the book: “Henry Gifford is what is known as a building scientist: He studies how buildings work and, just as important, why some don’t. He has written and published a remarkable book called Buildings Don’t Lie, with nearly 600 full-color pages stuffed with information, infrared photography, diagrams, and—the best part—quizzes to test your knowledge.
The book is as beautiful as it is exhaustive, covering airflow, water, light, sound, fire, pests, ventilation, air quality, and a lot more. You’ll learn how fire causes buildings to collapse; the best placement for pipes to avoid freezing; where your house might have thermal bridges that suck outside temperatures in; and the best shade style to let the sun heat your home in the winter, but not in the summer. You’ll worry at first that you didn’t know all this before, and you’ll be grateful that you do now.”
Nuggets mined from today’s interview:
Wrote the book because he sees a general information vacuum, where given advice from experts fits specific situations only and isn’t widely applicable.
“New buildings start life wet.” Because most construction trades add moisture to a building [and because materials get wet from rain on the truck or on the jobsite].
Efflorescence is when salts accumulate on surfaces. The cycle causing it is water getting in, as water moves it dissolves salts, when water evaporates salts are left behind. Efflorescence indicates where moisture is leaving the surface.
Surface wetting can be predictable. Windy side(s) of a building, above 2 stories wetting is less predictable because wind movement is much, much slower at ground level.
Overhangs and eaves only protect 1-2 stories underneath.
Corners of buildings get wetter and are colder because there is more exterior surface [than interior surface]
Insulation can be problematic because (with tongue in cheek) “removing insulation stops all moisture problem in building and improves durability”. Insulation inevitably makes one side of the wall cooler.
Cold wall=condensation with less heat available for material drying.
Passive home people use air barriers. Leaky air barriers allow an infinite [amount] of water vapor through resulting in mold growth on backside of gypsum board.
Can broadly classify the majority of buildings into 3 categories:
Stage 1- no barriers
Stage 2- barriers to heat, no barrier to air.
Stage 3- barriers to both heat and air.
Construction practice varies widely in every geographic region.
Important drip edge and flashing installation diagrams and photos showing the consequences of improper installation.
Weep-holes are holes near the bottom of an assembly to let liquid moisture drain out. Placing weep-holes too high is a common problem.
Subfflorescence- aka rising damp in Europe is when liquid is absorbed from soil upward into walls and salts are left behind. After salts fill the cavities additional salts exert tension/pressure which causes masonry to break. Fixes include: removal of heat source so are remains cold, removing on grout from both sides of wall and install of metal installation and installation of sacrificial coating. Capillary breaks (tar or plastic) in new construction prevent this from occurring.
More new buildings will need dehumidifiers than older buildings.
The “perfect wall” is how Joe Lstiburek describes a wall that works anywhere. Henry prefers the use “perfect sequence” to describe this type of wall. It places insulation further towards the exterior keeping the inside wall temperature closer to inside temperature of room, reducing peak and overall cooling loads, avoids air leakage through insulation getting to sheathing or other moisture vulnerable materials.
Henry Gifford’s contact info : 212-662-2768
https://buildingsdontlie.com/ link to order book
Z-Man signing off
Name the building scientist who stated “performance can only be defined when we know the limiting condition, i.e. the failure. Only then can we measure the actual performance as a distance to the failure criterion.