HardieWrap Weather Barrier

Jul 23, 2020Premier Building

HardieWrap weather barrier defends against weather elements that may get beneath external coverings of housing and other structures. It is a non-perforated, non-woven and water-resistant barrier. HardieWrap barrier is coated with a unique finish (MicroTech) that prevents water invasion while also allowing water vapor to escape the cavity of a wall. At 11-mil thick, this weather barrier ensures durability and strength. HardieWrap barriers are offered in two styles, each with a different climatic application – one used in cold/wet regions, and another in hot/humid areas.

Barrier Installation

HardieWrap weather barrier is recommended to be installed prior to installing doors or windows. It is intended to be installed over sheathing or dry framing. A sharp utility knife is recommended to cut the barrier. It should be applied a minimum of 6” around the corner of the nearby wall, print side facing out, and then secured using HardieWrap seam tape. When doing this, avoid interfering with any drainage details. Using staples (preferably galvanized) or roofing nails, fasten the weather barrier to sheathing material or studs, with a maximum of 18” increments both horizontally and vertically. The weather barrier’s lower edge should extend past the foundation interference and sill plate by a minimum of 1”. Upper layers of the weather barrier should overlap by a minimum of 6” beneath the horizontal edge. The horizontal seam line should then be taped down using HardieWrap seam tape. Any exposed weather barrier should ideally be covered up within 6 months from the date of installation. If applying HardieWrap weather barrier directly to Oriented Strand Board, or any other surface that does not require extra adhesion, a spray adhesive is suggested to be used in conjunction.

HardieWrap Flashing

When dealing with plumbing or electrical penetrations, it is recommended to secure a seal using flashing. James Hardie offers two different flashing products to be used alongside their weather barriers. HardieWrap Pro-Flashing is designed for a peel-and-stick installation. Meanwhile, HardieWrap Flex Flashing is stretchable and seals around windows and doors. Both flashing products are self-adhering, self-sealing and tear-resistant.

Flashing Installation

Begin the flashing proces by cutting HardieWrap flashing a minimum of 12” longer than the opening’s width. Center the flashing on the stud of the windowsill framing, and then stick the flashing into the opening. The rear edge of the flashing should extend onto the inner edge of the stud of the sill framing, and a minimum of 6” up every jamb framing stud. Note that it should never wrap onto the wall’s interior, and material should never be stretched along the sill of the jamb. HardieWrap Flex Flashing is intended to be cut and set around the opening of a window prior to being applied on top of the weather barrier. Prior to installing a window, apply sealant to the interior of the mounting flange on the outer edge of the window. Alternatively, apply a seal to the opening to confirm connection with the interior of the mounting flange of the window

For side jamb flashing, apply HardieWrap Pro-Flashing alongside the upright sides of the opening. Apply flash over the side window mounting flange. Extend flashing by at least 3” past the sill flashing that was installed prior (HardieWrap Flex Flashing). Be sure to also extend this flashing at least 3” past the top of the opening.

Lastly, to flash the head of the window, apply HardieWrap Pro Flashing over the mounting flange of the window alongside the header opening. Extend this flashing past jamb flashing by 3”. Apply pressure to ensure flashing stays in place. Use seam tape to seal all seams and joints.

For circular windows, begin by measuring the window and adding 12”. Cut this length of HardieWrap Flex Flashing to be used as head flashing. Remove roughly 20” of release paper and place flex flashing alongside the initial edge of window. Use pressure to secure flash into place. Continue this process for the entire circular section of the window. Each end of the head flashing must overlap sill flashing by a minimum of 6”.