James Hardie vertical siding offers a durable and aesthetically versatile cladding solution for single-family homes. Proper installation is critical to ensure performance, longevity, and warranty compliance. This article details the installation procedures and considerations for HardiePanel vertical siding, based on official James Hardie documentation and supplemental construction guidance. It covers preparation, fastening, joint treatment, and essential precautions.
General Requirements and Preparation
HardiePanel vertical siding is designed for installation over braced wood or steel studs, with a maximum stud spacing of 24 inches on center. Steel studs must be a minimum of 20 gauge (33 mils) and a maximum of 16 gauge (54 mils). The substrate, whether wood or steel, must be structurally sound and free of irregularities that could telegraph through the finished siding. Installation can also occur directly to a minimum 7/16 inch thick OSB sheathing.
A water-resistive barrier is mandatory and must be installed in accordance with local building codes, including proper lapping and flashing at penetrations and junctions. James Hardie manufactures HardieWrap® Weather Barrier, a non-woven, non-perforated housewrap that meets building code requirements. James Hardie explicitly states it assumes no responsibility for water infiltration issues.
Prior to installation, siding should be stored flat, dry, and covered to prevent moisture absorption. Installing wet or saturated siding can lead to shrinkage at butt joints. Panels should be carried on edge to minimize the risk of damage. The documentation emphasizes that James Hardie is not responsible for damage resulting from improper storage and handling.
Cutting and Handling
Cutting HardiePanel vertical siding requires specific tools and safety precautions. Outdoors, the preferred method is a circular saw equipped with a HardieBlade® saw blade and a vacuum dust collection system. Shears (manual, pneumatic, or electric) can also be used, but are not recommended for products thicker than 7/16 inch. Indoors, a circular saw with a dust collection feature and a HardieBlade is considered a better option, while a standard circular saw with a HardieBlade is acceptable.
Regardless of the cutting location, users must wear safety glasses and a mask to protect against fiber cement dust, which can be hazardous.
Fastening Procedures
Correct fastener positioning is crucial for a secure and aesthetically pleasing installation. Fasteners should be positioned 3/8 inch from panel edges and no closer than 2 inches from corners. Nailing directly into corners is prohibited. Framing must be provided at both horizontal and vertical edges to provide a nailing surface. HardiePanel vertical siding must be joined on a stud, and a double stud may be necessary to maintain minimum edge nailing distances.
When installing Sierra 8 siding, a double stud at panel joints is recommended to avoid nailing through grooves. Fasteners must be galvanized or stainless steel to prevent corrosion.
Joint Treatment
There are several acceptable methods for treating joints between HardiePanel vertical siding panels. Panels can be installed in moderate contact with each other. Alternatively, joints can be covered with battens, PVC or metal jointers, or caulked. However, caulking is not applicable to ColorPlus® finished siding.
For horizontal joints, Z-flashing must be installed to prevent water intrusion. The documentation illustrates the proper placement of Z-flashing and emphasizes the importance of maintaining a 1/4-inch gap between panels.
Specific Considerations for Sierra 8 Siding
The installation of Sierra 8 siding requires specific attention to joint support. The documentation recommends providing a double stud at panel joints to prevent fasteners from going through the grooves in the siding. This ensures a secure and stable installation.
Clearance Details and Building Codes
Adhering to clearance details is essential. The documentation references figures 3, 5, 6, 7, 8, 9, 10, and 11, which detail specific clearance requirements. Additionally, the finished grade adjacent to the siding must slope away from the building in accordance with local building codes, typically a minimum of 6 inches in the first 10 feet.
HardiePanel vertical siding is intended for use on flat vertical wall applications only. It should not be used in fascia or trim applications. The documentation explicitly states that stain, oil/alkyd base paint, or powder coating should not be applied to James Hardie products.
Rainscreen Installation
James Hardie recommends installing a rainscreen – an air gap – between the siding and the water-resistive barrier as a best practice. For projects involving a rainscreen, consulting a design professional is advised.
Expansion and Wind Load Considerations
For larger projects, particularly those with significant wall lengths, designers and architects should consider the coefficient of thermal expansion and moisture movement of the product. This information is available in the Technical Bulletin “Expansion Characteristics of James Hardie® Siding Products” on the James Hardie website.
James Hardie provides installation and wind load information for buildings with a maximum mean roof height of 85 feet. Installations exceeding 60 feet in height require consultation with James Hardie technical support.
Important Warnings and Warranty Information
The documentation includes a prominent warning: FAILURE TO FOLLOW JAMES HARDIE WRITTEN INSTALLATION INSTRUCTIONS AND COMPLY WITH APPLICABLE BUILDING CODES MAY VIOLATE LOCAL LAWS, AFFECT BUILDING ENVELOPE PERFORMANCE AND MAY AFFECT WARRANTY COVERAGE. It also warns of the potential for personal injury if health and safety regulations are not followed during cutting and installation. Users are directed to confirm they are using the correct HardieZone® product instructions by visiting hardiezone.com or calling 1-866-9-HARDIE.
Conclusion
Successful installation of James Hardie vertical siding requires meticulous attention to detail, adherence to manufacturer’s instructions, and compliance with local building codes. Proper preparation, correct fastening techniques, appropriate joint treatment, and consideration of expansion and wind load factors are all critical to ensuring a durable, aesthetically pleasing, and warrantied installation. Prioritizing safety during cutting and handling is also paramount.