7 Minutes of BS (#BuildingScience w/a BEAT): Recent Episodes
ProTradeCraft.com
Dark roofs absorb heat, and light roofs reflect it.Light roof shingles—combined with more insulation in the attic— can go a LONG way towards reducing the heat stress people in southern climates experience three seasons of the year.
Dr. Joe Lstiburek explains the fourth state of water: ADSORPED water. It exists on surfaces as tiny monolayers that can fill pores on the surface and cause mold. It also explains why expansive soils expand. If you thought you understood diffusion and capillarity, buckle up.
Vapor Diffusion Ports: Air Barriers That Let Moisture leave
Dr. Joe Lstiburek explains what Vapor Diffusion Ports are, how they work, why they're needed, and how to construct them—in about nine minutes.
The skinny version: they're like a modified ridge vent but for an unvented roof. They allow moisture to escape unvented roof assemblies without letting air leak out.
An overview of water, the liquid that makes life possible, rots buildings, and makes great wine.
In this episode, we are joined by Dr. Joe Lstiburek, out favorite crawlspace buddy, to talk about the origin of hot roof and cold roof labels.
This time on 7 Minutes of BS, Jonathan Smegal, M.S., describes his work at RDH Building Science Laboratories testing various wall sheathing materials for air tightness. The results are somewhat surprising but, truthfully, not a deal-breaker for most builders and remodelers.
Today's guest expert is Tanya Brown-Giammanco, formerly the Managing Director of Research at the Institute for Business and Home Safety (when we recorded this episode) and currently the Director of Disaster and Failure Studies at the National Institute of Standards and Technology (congratulations on the new gig, Tanya!).
Tanya explains how hail damage works, why hail damage matters, and how to minimize damage from hailstones by selecting the right roofing shingles.
This episode of 7 Minutes of BS explores how to install PVC siding and trim to reduce the effects of shrinkage.
PVC moves differently than wood, so it also behaves differently than wood.
Here's the inside dope.
Wildfire is different from wildland fire. Wildland fire is a regular part of a region’s ecology. Wildfire is a wildland fire that burns out of control. In this episode, we are joined by Daniel Gorham, a fire engineer at the Insurance Institute for Business and Home Safety.
We talk about what wildfire resistant construction is, how it works, why it matters so much these days, and how to do it right.
Guest Rob Matuga, Assistant Vice President for Health, Safety, Jobsite regulations at the National Association of Homebuilders (NAHB) discusses how to re-open jobsites safely.
Guest Jonathan Smegal, from RDH Building Science Laboratories, explains the mechanisms of heat flow, and how it can actually flow around insulation.
Guest: Dr. Anne Cope, Ph.D., P.E., Chief Engineer of the Insurance Institute for Business & Home Safety explains why calling it hurricane resistance puts so many people at risk.
Can a wall plummet from R-50 to R-12 because of the studs?
In this episode, we are joined by Jonathan Smegal, M.A. SC a Senior Project Manager with RDH Building Science Laboratories breaking down the nuts, bolts, what, why and how of R-value, insulation, and building assemblies.
This time we discuss dew point with Dr. Allison Bailes, aka, the Energy Vanguard.
“Dew point is the temperature at which water vapor in the air will condense on surfaces. So, if you have a surface that is at the dew point temperature of the water vapor that’s in the space around that surface, the water vapor will start condensing on that surface."
“Stucco is an exterior finish, and more specifically, we tend to think of it as an exterior plaster finish.
In some of the literature and in architectural dictionaries, stucco can be used for both exterior and interior finish work, but really in this day and age, we talk about plaster, particularly in North America, for interior work.”
—Sarah Gray, an engineer with RDH Building Science
"ViscoElasticity is what we’re talking about and that is the property of a material that exhibits the viscous nature of a liquid but also the elastic nature of a solid." —Allen Sealock, the product director for ZIP Systems with Huber Engineered Woods talking about the pressure-sensitive adhesives that are used on construction tapes.
Psychrometrics is the physics which deals with the process and properties of moist air, a combination of water vapor and dry air.
Low-e coatings screen infrared heat from moving through windows, either inward, outward, or both
Today Ray Garries, Vice President of Engineering and Innovation at MI Windows and Doors joins the show to explain what low-e coatings are, how they work, and why they matter for windows in your home.
Like an out-of-plumb wall, insulated and unvented roofs can work well—or not.
In this episode, we are joined by Jonathan Smegal, M.A. SC a Senior Project Manager with RDH Building Science Laboratories breaking down the nuts, bolts, what, why and how of an unvented roof assembly.
People have been growing houseplants in houses for a long time. They balance relative humidity, they clean the air, and they generally make the place homier.
But a marijuana grow-room is different—large bushes filling a bedroom, demanding resources that typical houseplants do not demand.
This can produce a lot of unwanted situations from moisture and indoor air quality problems, increases water and electrical usage, and possibly com plaints from the neighbors about aroma.
A lot more info is here: https://www.protradecraft.com/engineering-building-science-and-code-implications-marijuana-grow-rooms
If you can't build to stay dry, build to tolerate wet.
In this episode of 7 Minutes of BS, 'Dr. Joe' Lstiburek, PhD , P. Eng, ASHRAE Fellow, and founding principal of Building Science Corporation explains why flood water cleanup is critical, and how to rebuild with tolerance in mind.
Flood resistant construction is two things:
One approach is to build above the flood level, and it doesn't matter. That's an insanely logical way of doing it, you don't have to use special materials once you get above the flood level.
The second is that you assume the materials in the assembly are going to get wet, and saturated, so you build it in such a way that it is easy to dry and clean the building and pout it back together after the event happens.
A Drip edge is the leading edge of a flashing, sill, overhang or other linear, horizontal building element, designed to shed water.
they’re commonly found at enclosure details such as flashings, overhangs, or transition details between enclosure elements.
Like where one type of siding meets another. Or at the base of a wall where siding sets above a water table band.
"Science is a method of understanding how things work in the universe." Allison Bailles, Ph.D. is the gest for this episode of 7 Minutes of BS. We decided to back out of Building Science for a minute to talk about what science is, how it works, why it matters, and whether only ostrichs do not understand that climate change is a thing.
Three-pronged solution to indoor pollution: Isolate, eliminate, and ventilate.
For today's topic, we have Jim Shelton, Vice President, Panasonic Eco Solutions of North America as he breaks down the nuts and bolts of cleaning the air inside a building and keeping that way.
Heat stress is a net heat load to which a worker is exposed from the combined contributions of metabolic heat, environmental factors, and clothing worn, which results in the increase in heat storage in the body.
Too much heat stress can increase the risk for experiencing a heat-related illness such as heat stroke, heat exhaustion, heat cramps, heat rash— and DEATH.
Image: Guian Bolisay via Wikimedia Commons
"You can't simply go down to the hardware store and buy a box labeled air barrier."
This episode features Jonathan Smegal, M.A. SC a Senior Project Manager with RDH Building Science Laboratories breaking down the topic of air barriers in walls and roofs.
"A layer in the enclosure that stops the air movement from the interior to the exterior, and it often requires many components that are put together to make a durable continuous air barrier system."
In this episode, we are joined by Sarah Gray, an engineer with RDH Building Science Inc. to talk about using simple physics to outthink simple physics.
Using gravity to beat surface tension, and slope to beat gravity.
Vapor permeance is the property of a material – and in our discussions this will be building materials – which permits the passage of water vapor through it. Today's guest is Jonathan Smegal of RDH Building Science Laboratories... Some materials have high vapor permeance which means they allow a lot of water vapor to pass and other materials have significantly less vapor permeance, so they block water vapor movement and these are called vapor barriers or vapor retarders."
Thin foil can block massive amounts of heat transfer, but it needs a massive temperature difference to be effective. So, in residential construction, thermal insulation makes radiant barriers largely irrelevant.
Houses cannot expand and contract with changes in pressure like balloons can. Instead, they need paths for air to balance the pressure
Guest: Sarah Gray, P. Eng., RDH Building Science Inc.
Reservoir claddings include brick, stone, terra cotta, and even stucco, that are all porous materials. When exposed to rain or vapor diffusion, those pores will absorb and hold water until, the pores dry out. Just like a dam holds back lake water, the damned bricks hold the rain.
Stack effect is relentless: it is always working, when you’re awake or asleep, even during blackouts. And it feeds on itself.