Take control With
BUilding science
Why Standard Construction Fails…
Building code is the bare minimum—not a quality standard. Current building methods haven't evolved with modern materials, leaving many new homes vulnerable to the elements and the test of time.
Water Risk: 80% of structural damage comes from hidden moisture.
Contaminated Air: Drafty walls pull 60% of your indoor air from dirty crawlspaces.
Energy Waste: Unmanaged air leaks waste 40% of your heating and cooling.
Early Decay: Standard detailing leads to mold and premature structural failure.
Why Standard
Construction Fails
Building code is the bare minimum — not a quality standard. Current building methods haven't evolved with modern materials, leaving many new homes vulnerable to the elements and the test of time.
Water Risk: 80% of structural damage comes from hidden moisture.
Contaminated Air: Drafty walls pull 60% of your indoor air from dirty crawlspaces.
Energy Waste: Unmanaged air leaks waste 40% of your heating and cooling.
Early Decay: Standard detailing leads to mold and premature structural failure.
What is BUilding Science?
Building Science is how AGNEW HOMES NORTHWEST engineers a high-performance home that lasts. By integrating four critical management systems — Water, Air, Vapor, and Thermal — we eliminate the guesswork of standard construction.
This unified approach prevents structural decay and climatic failure, ensuring your home remains resilient over time.
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The Water Control Layer is the first line of defense against liquid moisture penetration. It consists of an integrated system of materials, such as exterior claddings, flashings, and the water-resistive barrier (WRB), designed to shed bulk water away from the wall assembly. Its primary function is to prevent rain and snowmelt from entering the structure, thereby guarding against mold, rot, and structural damage.
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The Air Control Layer (or air barrier) is a continuous, interconnected plane that restricts the movement of air into and out of the building enclosure. Controlling air movement prevents energy loss through convection and stops moisture-laden air from condensing within the wall assembly. This layer is crucial for maintaining both energy efficiency and superior indoor air quality.
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The Vapor Control Layer is designed to limit the movement of moisture in its gaseous form (water vapor) through the building's materials. This layer, often referred to as a vapor retarder or barrier, is strategically placed within the wall assembly based on climate. Its function is to prevent the condensation of water vapor inside the structure where it could damage insulation and encourage microbial growth.
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The Thermal Control Layer is the insulation system responsible for resisting the flow of heat. It is a continuous layer applied strategically across the entire exterior of the enclosure—walls, roof, and foundation—to minimize heat transfer via conduction, convection, and radiation. Effective thermal management maintains a comfortable indoor temperature, significantly reduces the demand on heating and cooling equipment, and is the primary driver of building energy efficiency.
Building Science is how AGNEW HOMES NORTHWEST engineers a high-performance home that lasts. By integrating four critical management systems — Water, Air, Vapor, and Thermal — we eliminate the guesswork of standard construction.
This unified approach prevents structural decay and climatic failure, ensuring your home remains resilient over time.
What is BUilding Science?
-
The Water Control Layer is the first line of defense against liquid moisture penetration. It consists of an integrated system of materials, such as exterior claddings, flashings, and the water-resistive barrier (WRB), designed to shed bulk water away from the wall assembly. Its primary function is to prevent rain and snowmelt from entering the structure, thereby guarding against mold, rot, and structural damage.
-
The Air Control Layer (or air barrier) is a continuous, interconnected plane that restricts the movement of air into and out of the building enclosure. Controlling air movement prevents energy loss through convection and stops moisture-laden air from condensing within the wall assembly. This layer is crucial for maintaining both energy efficiency and superior indoor air quality.
-
The Vapor Control Layer is designed to limit the movement of moisture in its gaseous form (water vapor) through the building's materials. This layer, often referred to as a vapor retarder or barrier, is strategically placed within the wall assembly based on climate. Its function is to prevent the condensation of water vapor inside the structure where it could damage insulation and encourage microbial growth.
-
The Thermal Control Layer is the insulation system responsible for resisting the flow of heat. It is a continuous layer applied strategically across the entire exterior of the enclosure — walls, roof, and foundation — to minimize heat transfer via conduction, convection, and radiation. Effective thermal management maintains a comfortable indoor temperature, significantly reduces the demand on heating and cooling equipment, and is the primary driver of building energy efficiency.
Your Home
For Generations
With the four control layers in place, you can enjoy an uncompromising living environment. We prioritize structural integrity so your home remains a high-performance asset for generations.
Water Shield: Multi-layer drainage and specialized shields keep your home dry.
Purified Air: Airtight sealing and mechanical filtering ensure purified air 24/7.
Thermal Control: Precision sealing and insulation maintain perfect temperatures.
Ultimate Durability: A high-performance enclosure ensures a legacy home that lasts.
The Red line in
Building Science
The RED LINE is the definitive, airtight seal surrounding your home. This unbroken boundary acts as the ultimate shield, separating your conditioned living space from the external environment.
Without a solid RED LINE, your home is left vulnerable to unmanaged air leaks and moisture intrusion. This creates a cycle of condensation and rot that destroys structural integrity from the inside out.
We move beyond standard building flaws to ensure your home stays dry, healthy, and permanent.
Your home for generations
A high-performance home requires four integrated Control Layers: Water, Air, Vapor, and Thermal. While standard methods treat a build as separate parts, we engineer your home as a unified system. This eliminates failure points to create a permanent, resilient shield.
Ultimate Durability: A high-performance enclosure ensures a legacy home that lasts.
Water Shield: Multi-layer drainage and specialized shields keep your home dry.
Purified Air: Airtight sealing and mechanical filtering ensure purified air 24/7.
Thermal Control: Precision sealing and insulation maintain perfect temperatures.
The Red line in
Building Science
The RED LINE is the definitive, airtight seal surrounding your home. This unbroken boundary acts as the ultimate shield, separating your conditioned living space from the external environment.
Without a solid RED LINE, your home is left vulnerable to unmanaged air leaks and moisture intrusion. This creates a cycle of condensation and rot that destroys structural integrity from the inside out.
We move beyond standard building flaws to ensure your home stays dry, healthy, and permanent.
The Breathing
House Myth
The notion that a house should breathe is a common misconception that leads to costly repairs. A home doesn't need to breathe — it needs to dry.
When a house breathes through leaks, it traps moisture inside your walls, leading to rot, mold, and poor air quality.
We eliminate this risk by establishing a continuous RED LINE — protected from the elements by the control layers.
The Breathing
House Myth
The notion that a house should breathe is a common misconception that leads to costly repairs. A home doesn't need to breathe — it needs to dry.
When a house breathes through leaks, it traps moisture inside your walls, leading to rot, mold, and poor air quality.
We eliminate this risk by establishing a continuous RED LINE — protected from the elements by the control layers.
Standard Construction VS
Agnew Homes NW
Standard Wall Assembly
Siding is nailed directly through the house wrap into the plywood, puncturing your home’s protective skin thousands of times and trapping moisture against the structure.
House wrap relies on tape and staples that eventually fail, allowing air and water to bypass the seams. Even a perfect installation remains a leaky barrier that cannot provide a permanent, airtight seal.
Plywood is installed with gaps at every joint, creating a sieve for energy loss. These unsealed seams allow conditioned air to escape and humidity to seep in, rotting your frame from the inside out.
Interior insulation alone is a fundamental design flaw. Without an exterior layer, every wooden stud acts as a bridge that carries heat straight through the wall, tanking your home's overall efficiency.
Agnew Homes NW
Wall Assembly
Modern siding is mounted to a rainscreen, physically separating it from your home’s structure. This air gap keeps the panels pristine while ensuring the wall behind them stays dry and resilient for decades.
Vertical furring strips create a vital drainage plane that allows air to circulate and moisture to escape. This "breathing room" prevents the trapped humidity that rot-proofs the entire assembly.
Zip System sheathing creates a seamless, airtight shell that eliminates the leaks of traditional house wrap. This RED LINE of defense seals every gap, while continuous external insulation stops heat loss before it ever reaches your studs.
By sealing the exterior with a RED LINE and continuous insulation, the heavy lifting is already done. This allows for a thinner interior layer, as the external blanket has already neutralized the temperature swings and stopped the thermal bridging.
Standard Wall Assembly
Siding is nailed directly through the house wrap into the plywood, puncturing your home’s protective skin thousands of times and trapping moisture against the structure.
House wrap relies on tape and staples that eventually fail, allowing air and water to bypass the seams. Even a perfect installation remains a leaky barrier that cannot provide a permanent, airtight seal.
Plywood is installed with gaps at every joint, creating a sieve for energy loss. These unsealed seams allow conditioned air to escape and humidity to seep in, rotting your frame from the inside out.
Interior insulation alone is a fundamental design flaw. Without an exterior layer, every wooden stud acts as a bridge that carries heat straight through the wall, tanking your home's overall efficiency.
Agnew Homes NW
Wall Assembly
Modern siding is mounted to a rainscreen, physically separating it from your home’s structure. This air gap keeps the panels pristine while ensuring the wall behind them stays dry and resilient for decades.
Vertical furring strips create a vital drainage plane that allows air to circulate and moisture to escape. This "breathing room" prevents the trapped humidity that rot-proofs the entire assembly.
Zip System sheathing creates a seamless, airtight shell that eliminates the leaks of traditional house wrap. This RED LINE of defense seals every gap, while continuous external insulation stops heat loss before it ever reaches your studs.
By sealing the exterior with a RED LINE and continuous insulation, the heavy lifting is already done. This allows for a thinner interior layer, as the external blanket has already neutralized the temperature swings and stopped the thermal bridging.
Where the Red line breaks in
Standard Construction
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Baseboard Gaps: Tiny spaces between the drywall and subfloor allow air to move freely behind your walls.
Electrical Outlets: Air often flows through internal wall cavities and leaks out from behind your outlet faceplates.
Pocket Door Cavities: The hollow frames for sliding doors often open directly into unconditioned and unsealed attic spaces.
Knee Wall Breaks: Short walls in finished attics frequently hide large gaps in the home's thermal and air boundary.
Cabinetry Penetrations: Unsealed holes for plumbing under sinks are often overlooked points of significant internal air movement.
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Windows & Doors: Gaps around rough openings and worn weatherstripping allow external air to infiltrate your living space.
Service Entrances: Penetrations for gas, cable, and phone lines create direct pathways for significant outside air leakage.
Outdoor Electrical: Unsealed light fixtures and outlet boxes pull humid exterior air into your home's wall cavities.
Exterior Hose Bibs: Holes for water faucets frequently lack the necessary gaskets to maintain a continuous air seal.
Ventilation Terminations: Damaged dryer vent flaps or unsealed pipe penetrations compromise the integrity of the home’s boundary.
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Wall Top Plates: Holes drilled for electrical and plumbing lines allow conditioned air to escape into the attic.
Attic Access Hatches: Uninsulated or poorly sealed panels create a massive chimney effect for heat and energy loss.
Recessed Lighting: Non-airtight "can" lights pull warm air from living spaces and dump it into the cold attic.
Plumbing Stack Vents: Gaps around PVC pipes exiting through the roof allow moisture and air to bypass the seal.
Exhaust Fan Housing: Improperly sealed bathroom fans create a permanent break in the ceiling’s critical vapor barrier.
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Crawl Space Vents: Traditional vents invite humid air and ground vapor directly into your home’s structural base.
Sill Plate Joints: The critical connection where wood framing meets the concrete foundation is a common leakage point.
Rim Joist Gaps: Perimeter floor joists are frequent failure points where external air bypasses your home’s thermal insulation.
Foundation Cracks: Small fissures in concrete walls allow soil gases and moisture to penetrate the lower control layers.
Access Hatches: Loose-fitting crawl space doors act as a constant breach in your home’s lower red line boundary.
Standard - Vented
In standard building vents allow humid air to enter and get trapped under your home. This moisture condenses into mold and rot, compromising your foundation and your air quality.
Agnew Homes NW - Sealed
Using building science we eliminate vents in favor of a fully sealed exterior enclosure. By blocking moisture and vapor from the start, we create a bone-dry environment that protects your structure for life.
Standard - Leaks
Standard crawl spaces often have dirt floors or vapor barriers that aren't air-sealed to the foundation walls. This "vapor drive" leads to high humidity, wood rot, and poor indoor air quality that allows for mold growth.
Agnew Homes NW - Sealed
As seen in this photo during a basement pre-slab installation, our heavy-duty vapor barrier is air-sealed directly to the foundation walls. This creates a permanent, unbroken seal that ensures absolutely no moisture or compromise can enter your home from underneath.
Standard - The Results
Poor moisture and aircontrol leads to a cycle of structural decay and toxic mold growth. This compromise doesn't just damage your wood and foundation; it ruins your indoor air quality by pulling damp, polluted air from the crawl space into your living areas.
Agnew Homes NW - The Results
Whether it’s a crawlspace or a basement, our approach guarantees a healthy, bone-dry structure that is built to last centuries. By eliminating moisture at the source, we provide superior air quality and unmatched durability, protecting both your family’s health and your long-term investment.