Vapor is one of the most misunderstood parts of building science—and in many assemblies, it helps buildings dry rather than making them wet. In Part 3 of the Back to Basics series, Steve, Jake, and Pete break down vapor control, vapor permeability, drying potential, and why decades of confusing code language created so much fear around vapor.

As Steve puts it, “Vapor is not a liability, it is an asset.” Buildings get wet. In most climates and assemblies, the ability to dry through vapor diffusion is an important part of keeping moisture-sensitive materials safe.

The crew explains why you need to understand the vapor permeability of every layer in an assembly, where to find reliable material data, and when to go directly to manufacturers for standardized test results. They also get into indoor humidity measurement and why accurate hygrometers are more important—and more expensive—than many people realize.

This is Part 3 of the four-part Back to Basics series covering Water, Air, Vapor, and Thermal control.

Pete’s Resources:

• Water in Buildings: An Architect’s Guide to Moisture and Mold
• Vapor Profiles Help Predict Whether a Wall Can Dry
• ICC R702.7 – Vapor Retarders
• BSC Building Materials Property Table
• Measuring and Understanding Humidity
• ASTM E96: Explaining Water Vapor Transmission Rate Testing
• Building Science Advisor

Airtightness is one of the most important—and most measurable—parts of building performance. In Part 2 of the Back to Basics series, Steve, Jake, and Pete break down how air control layers work, why continuity matters, and how blower door testing exposes the difference between theory and reality.

The crew starts with several principles that apply across multiple control layers: staying in one plane makes continuity easier, simpler details are more likely to succeed, and combining control functions in a single material can reduce opportunities for failure. They also revisit one of their favorite ideas: eliminate “confused spaces.” Attics, crawlspaces, and other areas should clearly belong either inside or outside the building enclosure.

Then the conversation gets specific to airtightness. Blower doors do not lie. ACH50 provides the quantitative result, but finding the actual leaks—their size, location, and number—is just as important. The boys discuss why one blower door test is rarely enough, how wind, stack effect, and fans drive air leakage, and why two mediocre air control layers do not equal one good one.

For renovations, the sequence is simple: blower door test first, air seal second, insulate third.

Pete's Resources:

EPA – Moisture Control Guidance for Building Design, Construction, and Maintenance

ENERGY STAR Thermal Bypass Checklist

A House Needs to Breathe...Or Does It? An Introduction to Building Science by Allison Bailes

Water is the number one enemy of building durability—and the first control layer every builder, architect, and designer needs to understand. In Part 1 of a four-part Back to Basics series, Steve, Jake, and Pete break down the principles of water management that every high-performance building depends on.

The conversation starts where most rain begins: the roof. From roof design and drainage to flashing strategies and capillary action, the crew explores how liquid water moves through buildings and why good design is the first line of defense. They also discuss how patterns of water damage in both historic and modern buildings reveal timeless lessons about moisture management.

One of the episode's most interesting discussions comes when building science theory meets real-world practice. Steve approaches water management from an architect's perspective, while Jake explains the practical realities builders face every day. The result is a thoughtful conversation about balancing ideal building science with constructability in the field.

This is Part 1 of a four-part series covering the four fundamental building control layers: Water, Air, Vapor, and Thermal.

Pete's Resources:

• Joe Lstiburek – Moisture Control for Buildings
• EPA – Moisture Control Guidance for Building Design, Construction, and Maintenance
• Water in Buildings: An Architect's Guide to Moisture and Mold

How do you design a home for floods, wildfires, earthquakes, hurricanes, tornadoes, or ice storms? In this episode, Steve, Jake, and Pete explore what it really means to build for extreme events—and why there’s no one-size-fits-all solution.

Drawing from real-world experience, Steve and Jake discuss how high-performance homes can be adapted to withstand the specific hazards of a site’s climate and geography. From flood-resistant foundations and safe rooms to wildfire resilience and high-wind detailing, the conversation focuses on matching building strategies to the level of protection each client wants to achieve.

The discussion also highlights an important philosophy: building professionals aren’t there to judge a client’s concerns—they’re there to understand the risks, explain the tradeoffs, and design solutions that meet the client’s goals.

Whether you’re building in a floodplain, earthquake zone, hurricane corridor, or wildfire-prone area, this episode explores the principles behind resilient, durable homes designed for the unexpected.

Pete’s Resources:

FEMA Breakaway Walls Guidance

FEMA Safe Room Design Guide

FEMA Flood Openings in Foundation Walls

Simpson Strong-Tie High Wind Construction Guide

FamilySafe Storm Shelters

IBHS Home Disaster Guides

Three listener questions lead to three very different building science discussions—from cold-climate roof assemblies to aging-in-place design and innovative foundation systems.

The episode begins with a Climate Zone 7 tongue-and-groove ceiling question, comparing ZIP sheathing and smart vapor retarders for airtightness and moisture control beneath a vented attic. From there, a question about zero-threshold exterior doors expands into a broader conversation about Universal Design and designing homes that remain accessible throughout every stage of life.

The final discussion explores alternatives to traditional concrete foundations, including wood-based and prefabricated foundation systems. Steve and Jake weigh in on whether they would actually build with these systems, while Pete introduces an intriguing below-grade SIP foundation from Extreme Panel Technologies that was new to all three hosts.

Three listener questions, dozens of practical takeaways, and another deep dive into the details that shape better buildings.

Pete’s Resources:

Climate Zone 7 T&G Ceiling

• SBA – ZIP Ceiling
• SBA – Smart Vapor Retarder Ceiling

Universal Design & Aging in Place

• Build Show – Forever Home Series
• European Exterior Doors
• Automatic Drop-Down Door Seals
• The Universal Design Project
• Mississippi State Barrier-Free Design Guides

Alternative Foundations

• Extreme Panel Technologies Foundations
• CCA Treated Plywood Specification

How much can a building affect human health—and what happens when occupants become highly sensitive to their environment? In this episode, Steve and Pete are joined by retired building scientist and pulmonary physician Nathan Yost for a thoughtful discussion on Multiple Chemical Sensitivity (MCS) and its relationship to building performance.

Nathan shares insights from decades of experience working with clients dealing with chemical sensitivities, along with more recent medical understanding surrounding pregnancy, hormonal changes, and biochemical sensitivities. The conversation explores where building science intersects with health concerns, how indoor environments can influence occupant comfort, and what building professionals should consider when designing for sensitive individuals.

Steve also shares examples from recent projects where MCS concerns led to major changes in materials, specifications, and interior design decisions. The discussion even ventures into the controversial topic of electromagnetic fields and so-called “dead zones,” highlighting the challenges of balancing occupant concerns with evidence-based building practice.

It’s a fascinating conversation about the overlap between buildings, health, and the limits of what construction professionals can realistically control.

Pete’s Resources:
Helping People with Multiple Chemical Sensitivity
Medical Conditions Building Professionals Need to Know About
Prescriptions for a Healthy House (4th Edition)
NIH – Electric & Magnetic Fields
BuildingGreen – Building Design and EMF

Four listener questions. Four very different building science challenges. One highly technical episode.

Steve, Jake, and Pete tackle a collection of building puzzles that span foundations, roofs, wall assemblies, and moisture management. The discussion starts with expansive soils and why successful construction often depends on engineered foundation systems designed to accommodate soil movement. From there, the crew examines attic radiant barriers, where they work best, and why climate matters when evaluating their performance.

The conversation then shifts to a cold-climate stucco retrofit involving exterior rigid insulation, reinforcing a core building science principle: prioritize the four control layers in the right order—water first, airtightness second, drying potential third, and thermal control fourth. Finally, they unpack the risks of a “diaper wall” assembly, where moisture-sensitive materials become trapped between low-permeance layers, and discuss how weather protection and airtightness can reduce those risks.

A highly technical episode packed with practical problem-solving, building science fundamentals, and real-world application.

Pete’s Resources:

• Post-Tension Slabs for Expansive Soils
• Evolution of Foundation Design for Expansive Soils
• ORNL Thermal Performance Evaluation of Attic Radiant Barrier Systems
• Building America Solution Center – Attic Radiant Barriers
• EPA Moisture Control Guidance
• GBA – Vapor Profiles Help Predict Whether a Wall Can Dry

Do certifications, standards, and professional credentials actually lead to better buildings—or just more paperwork? Steve, Jake, and Pete tackle one of the more uncomfortable questions in the building industry: why so many standards fail to consistently produce better outcomes in the real world.

The conversation ranges from ASTM standards and manufacturer testing to architectural credentials and industry certifications, questioning where standards genuinely help—and where culture, habits, and resistance to change become the bigger obstacle. Steve makes the case that the industry’s biggest challenge may not be technical at all, but cultural.

The crew also digs into one of Steve’s standout ideas: “chase friction.” Instead of accepting inefficient details, weak processes, or recurring failures, the goal should be to constantly look for the points of resistance that reveal where buildings can improve.

It’s an opinionated discussion with a few disagreements along the way, but the central takeaway is clear: meaningful progress only happens through rigorous education—for both building professionals and clients alike.

Pete’s Resources:

• Treasure of the Sierra Madre clip
• ISO Construction Quality Standards
• Construction Education & Certifications
• Chasing Friction Article

Can ZIP-R panels work on a roof—and should they? Steve, Jake, and Nick Sabol from Huber’s Technical team dig into a topic that’s getting a lot of attention in the field.

This episode breaks down the full set of considerations behind putting insulated sheathing on the roof deck: structural loading, fastening and shear, hygrothermal behavior, condensation risk, and long-term durability. The crew looks at where the idea makes sense, where it doesn’t, and what you need to understand before trying it on a real project.

It’s a detail-heavy conversation that connects theory to field conditions—exactly where most “good ideas” succeed or fail. And for Pete’s top resource on this one? Call Steve.

Pete’s Resources:

• ICC-ES Report 1473
• Roofs & Attics: The Building Science of “the Lid”
• Huber Technical Support: [email protected]

Do wildfire zones actually change how rainscreens should be detailed—and where does conventional thinking fall short? Nick Sabol from Huber’s Product Engineering team is back with Steve and Pete to continue the deep dive into wall details that actually work.

This episode focuses on rainscreen strategies in wildfire-prone areas and challenges the assumption that every risk requires a completely different assembly. The discussion also highlights Steve’s perspective on using materials like ZIP sheathing in unconventional ways—prioritizing performance and continuity over tradition when it makes sense.

From fire exposure considerations to air barrier continuity, the conversation connects real-world risk with practical detailing decisions. It’s a continuation of the Part I discussion, with a sharper focus on where building science meets evolving conditions like the Wildland Urban Interface.

Pete’s Resources:

• ICC Harmathy’s Ten Rules
• US Fire Administration – Wildland Urban Interface
• IBHS External Sprinklers for Wildfire Defense
• Build Show – Air Barrier Continuity (Wall to Ceiling)
• Build Show – Air Barrier Continuity (Ceiling)