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How to Install HardieTrim

HardieTrim boards complement other Hardie fiber cement products such as HardiePlank lap siding, HardieShingle shingle siding and HardiePanel vertical siding. James Hardie's HardieTrim boards are available in either climate zones HZ5 or HZ10 boards. HZ5 boards are recommended for climates in Canada and the upper (approximately) two-thirds of the United States. HZ10 boards are recommended for the lower one-third of the United States.

James Hardie also makes certain dedications to "green" building, including using low-toxicity raw materials near manufacturing facilities and manufacturing products with 15-year finish warranties.


  1. Install a water-resistive barrier in accordance with local building codes; James Hardie assumes no responsibility for water infiltration.
  2. Position your trim in the desired location. Follow building codes and manufacturer's instructions.
  3. Fasten the trim, positioning finish nails at least 1/2-inch from the edge of the trim. Position fasteners at least 1-inch (for HZ5) or at least 3/4-inch (for HZ10) from the edge of the trim. When using HardieTrim with ColorPlus technology, you must use finish nails. For 4-inch pre-built corners, use one nail every 16 inches (attaching boards together), plus one nail every 16 inches on each board. For 6-inch pre-built corners, use one nail every 16 inches (attaching boards), plus two nails every 16 inches. On 4- and 6-inch site-built corners or other areas, use two nails every 16 inches. On 8- and 12-inch site-built corners or other areas, use three nails (8-inch with HZ5 or 8- and 12-inch with HZ10) every 16 inches or four nails (12-inch HZ5) every 16 inches.
  4. Remove the laminate sheet directly after nailing on ColorPlus HardieTrim, unless painting or touching up the nail. Remove the laminate sheet after touching up the nail, but before the paint dries.
  5. Build corners or order pre-built corners. Each side of a corner must attach to the wall.

Things You Will Need

  • Water-resistive barrier (such as HardieWrap)
  • Hammer or nailer
  • Stainless-steel, 16-gauge, 2-inch minimum finish nails (wood-frame construction)
  • ET&F (or equivalent fasteners/screws for steel-frame construction)
  • Smooth shank siding nails (interchangeable with 16-gauge 2-inch finish nails for HZ10 boards)

Tips

  • Maintain 2-inch clearances between decks, driveways and similar areas. Maintain a 2-inch clearance between your roofing and the bottom of the trim.
  • You can also use HardieTrim boards as frieze boards, rake trim, fascia or band boards.
  • Use elastomeric joint sealant (ASTM C920 Grade NS; class 25 or higher) or latex joint sealant (ASTM C834 compliant)

About the Author

With a professional background in gardening, landscapes, pests and natural ecosystems, Jasey Kelly has been sharing her knowledge through writing since 2009 and has served as an expert writer in these fields. Kelly's background also includes childcare, and animal rescue and care.