As temperatures drop, homes face some of the harshest conditions of the year. While builders often think about insulation, air sealing and heating efficiency during winter, one of the most overlooked risks is moisture trapped behind the siding. Winter weather systems bring a combination of cold rain, melting snow and fluctuating temperatures, all of which can stress the building envelope.
This is where drainable house wraps outperform traditional flat wraps — especially those using advanced mesh structures like ALTA® 360°, powered by CLAF® technology. Winter is the time when drainage isn’t just helpful. It’s essential.
The Winter Moisture Challenge
1. Freeze/Thaw Cycles Add Stress Behind the Wall
Even small amounts of moisture that get behind the siding can turn into major problems once the temperature swings.
Water expands when it freezes.
When that happens behind the cladding, it can create:
- Sheathing damage
- Cracked siding panels
- Fastener movement
- Accelerated rot around penetration points
A house wrap that only blocks water, but doesn’t remove it, leaves the wall assembly vulnerable.
2. Winter Introduces Slow, Hidden Moisture
Cold weather slows evaporation. Snowmelt and cold rain linger longer on exterior surfaces and walls dry more slowly during winter months. Any moisture that slips behind siding stays there longer — increasing the chance of long-term damage.
3. Condensation Happens More Often Than Builders Think
Cold exterior surfaces + warm interior walls = a prime environment for condensation behind the sheathing. When the wall can’t drain, condensation becomes trapped and increases the risk of mold growth.
Why a Drainable WRB Makes All the Difference
A high-performance water-resistive barrier should do two things:
- Stop bulk water from getting in
- Move trapped water out as quickly as possible
Flat house wraps struggle with the second part because they do not create space for water to migrate downward. ALTA® 360 solves this with a built-in drainage system made possible by its CLAF® mesh layer.
How ALTA® 360’s CLAF® Mesh Creates Drainage
CLAF® is an engineered open mesh that forms natural vertical channels between the wrap and the siding. Instead of relying on coatings or embossed textures, the mesh itself becomes the drainage plane.
This design allows ALTA® 360 to:
- Quickly direct water down and out of the wall
- Maintain drainage efficiency even under compression
- Exceed the ASTM E2273 drainage test standard
- Reduce the risk of freeze/thaw damage
- Keep the sheathing drier during the months when drying potential is lowest
Because drainage is built into the structure of the mesh, performance stays consistent for the life of the product.
Winter Is the Season That Tests a WRB’s Strength
Builders often face the toughest installation conditions in winter:
- Higher winds
- Colder temperatures
- Rigid building materials
- Moisture-heavy weather systems
This makes the strength of the WRB just as important as its drainage performance.
ALTA® 360’s CLAF® layer reinforces the wrap, giving it high tear and puncture resistance. Installers benefit from better handling in windy or icy conditions, reducing the risk of blowouts and rework.
A Drier Wall Is a Healthier, Longer-Lasting Wall
When a WRB helps the wall assembly dry faster, it protects the structural integrity of the building and improves long-term performance.
Better drainage means:
- Less mold risk
- Lower chance of insulation degradation
- Reduced sheathing rot
- Fewer callbacks for builders
- Better long-term energy performance
This matters all year, but winter is where the difference becomes visible.
Why ALTA® 360 Is Built for Winter Conditions
ALTA® 360 combines water resistance, built-in drainage channels and reinforced strength in a two-layer design. It’s engineered to keep walls dry during the toughest seasons, from the first freeze through early spring thaw.
When winter puts the building envelope to the test, ALTA® 360 delivers the protection builders rely on.