The Science behind Sure Cavity

Read why Sure Cavity’s True Channel Technology works better than others in all facets of moisture mitigation within the rainscreen

In this Insight, we examine the principles of heat and moisture transfer in building envelopes and the role of innovative drainage systems like Sure Cavity in managing these factors. Specifically, attention is focused on the mechanisms of conduction, convection, and radiation and their implications for moisture control. Sure Cavity’s unique corrugated channel design is highlighted for its effectiveness in mitigating moisture accumulation through improved air circulation, drainage, and thermal insulation.

1. Heat Transfer by Conduction

Sure Cavity®’s corrugated channel pattern disrupts heat transfer by conduction by completely eliminating direct contact between two materials. The air voids created by the corrugation act as an insulating layer, reducing conductive heat flow. These voids also provide space for air circulation, which may contain water vapor that can be moved out of the building envelope through convection.

(Refer to Figure #1)

2. Heat Transfer by Convection

The open channels on both sides of the Sure Cavity allow for unrestricted air movement. This facilitates convection, where warm air rises and cooler air falls, carrying heat and moisture (in the form of water vapor) out of the building envelope through properly designed ventilation details. This process helps manage moisture and regulate temperature within the structure.

(Refer to Figure #2)

3. Heat Transfer by Radiation

Sure Cavity, when exposed to indirect radiant heat, can absorb and temporarily store energy, which is later released into cooler adjoining materials through conduction. While direct exposure to radiant heat sources is uncommon in its typical installation, radiant heat can drive
moisture deeper into building materials. Once the moisture encounters Sure Cavity’s channels, it can be affected by convection and moved out of the envelope.

(Refer to Figure #3)

Key Impacts on Moisture Management

Of the three heat transfer mechanisms—conduction, convection, and radiation—the most significant for moisture management in exterior building envelopes are conduction and convection. These processes directly affect moisture concentration and air movement, which are critical factors in preventing and managing water intrusion. When combined with effective building science design, these forces can be harnessed to move unwanted moisture out of the building envelope.

(Refer to Figures #1 & #2 Below)

Moisture Accumulation and Condensation

Moisture tends to accumulate when it encounters a surface less permeable than the pathway it traveled. This typically happens during leaks but can also occur due to condensation. Sure Cavity’s corrugated channels mitigate this by allowing moisture to condense on the surface if the temperature reaches the dew point. Once condensed, the water drains out of the building envelope due to gravity. This unique feature can occur on both sides of the corrugated pattern, providing a dual drainage mechanism unmatched by other rain screen drainage plane products. This capability is especially effective when the direction of moisture ingress is well understood.

(Refer to Figures #4 & #5 Below)

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