Building envelope solutions for managing moisture in low-rise wood frame construction.

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Protect the elegant finish of fiber cement by incorporating a drainage gap behind the cladding which provides trapped moisture a path to escape.

Major siding manufacturers have recently issued drainage requirements behind their products. Drainable housewraps with a drainage efficiency of at least 90% when tested according to ASTM E2273 are now recommended or required behind certain exterior sidings like HardiePanel and Boral® TruExterior.

Fiber Cement Envelope Solutions Using Standard OSB Sheathing

System Details

For cementitious sidings like Fiber Cement that absorb water – we recommend a drainable housewrap with a true drainage space (at least 1mm). Testing shows that the best performing drainage gap in terms of drainage efficiency and speed of drainage occurs at 1mm or above. Install a drainable wrap over sheathing with the drainage gap facing out towards the siding to protect the fiber cement from damage.

For products that are impermeable to moisture like Boral® TruExterior, a drainable housewrap is required. In this case, we are not concerned about the siding absorbing water, but reducing hydrostatic pressure behind the siding that can cause water to be forced into penetration points. A gap of 1mm or greater relieves this pressure and allows the wall to drain effectively.

Fiber Cement Envelope Solutions Using Pre-Weatherized Sheating

When using a pre-weatherized sheathing, like Huber's Zip System®, you can add in an additional drainage plane by using a drainable housewrap like HydroGap.

Adding HydroGap is a CYA solution for an imperfect application or installation of preweatherized sheathing (e.g., tape is not installed with j-roller, coating is damaged, penetration points or nail holes are not treated, etc.). Preweatherized sheathing provides a very effective air barrier, while HydroGap provides an excellent water barrier for high performing building envelope solution.

Fiber Cement Envelope Solutions Using Rigid Foam

Important Note

Rigid foam is a flat-to-wall low perm board that can contribute to moisture damage in a water entry event if there is no pathway for water to escape. HydroGap provides a means to drain water underneath the foam without reducing the thermal resistance of the wall. In a fiber cement or composite siding application, apply drainable housewrap directly over sheathing with gap facing the exterior towards the siding and continue with insulation and siding layers.

Product Details

WRB & Drainage Layer
HydroGap Drainable Housewrap

HydroGap Drainable Housewrap protects the elegant finish of fiber cement siding by creating a gap via 1mm spacers which promote drainage behind the cladding. These unique spacers remove 100 times more bulk water from walls than standard housewraps. Trapped moisture will cause damage to your wall system and creates an environment for mold and rot.

Advanced Protection Details
HydroFlash - Self Adhered Flashing

Use HydroFlash for all of your window and door flashings needs. HydroFlash is an aggressive peel-and-stick self adhered flashing that out-performs other butyl and rubberized asphalt versions. The specially formulated bloc co-polymer can be applied to damp surfaces and installed down to 0° F.

HydroCorner - Pre-formed Sill Corners

HydroCorner Sill Treatment is an affordable option for protecting a window sill from moisture intrusion. Place one HydroCorner in each of the bottom sill corners, and then cover with a piece of HydroFlash for a quick and easy-to-install sill treatment.

The journey to protecting your investment starts here!

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