HardiePlank Installation

James Hardie is a major manufacturer of fiber-cement siding products. Their installation recommendations will be relevant to most fiber-cement siding.


  • Studs 24" OC maximum spacing;
  • Flat vertical wall installations only;
  • 1/4" starter strip should be installed at first (bottom) course;
  • 1 1/4" min. course overlap;
  • Trim should not overlap siding. Siding should terminate at trim with 1/8" min. caulked gap;
  • Dryer) Vent penetrations: Vents should be installed against a block installed against wall sheathing with head flashing installed and siding installed as if the block were trim;
  • Field-cut edges should be caulked, primed, or painted.


  • Water-resistive barrier required.


  • Typically blind-nailed. Face-nailing may be required in some jurisdictions (like high-wind);
  • Corrosion resistant nails required. SS recommended in coastal and humid climates;
  • No aluminum nails, staples, or clipped-head nails;
  • 3/8" min. from vertical edges;
  • 3/4" min. from horizontal edges;
  • Nails should not be over-driven.
  • Countersunk nails should have holes filled;


  • 6" min. above grade;
  • 2" min. above flatwork and other hard surfaces;
  • 2" min. above deck planking. Z-flashing required at deck ledger should be installed so that vertical lip is behind siding;
  • 1" min. above roof-covering material (2" after May 2016);
  • 1/4" clearance above horizontal (headwall) flashing, no caulking;
  • 1/8" minimum gap at butt joints (joint flashing preferred but not required) and where siding butts trim (caulking required);
  • Proper flashing (windows, doors, vent terminations, etc.).


  • Fiber-cement siding on homes built between 1920 and the 1960s are likely to contain some percentage of asbestos. That percentage can only be determined by laboratory testing.
  • Fiber-cement siding installed after 1973 is very unlikely to contain asbestos.
  • No laws require removal of fiber-cement siding containing asbestos.
  • Fiber-cement siding containing asbestos is only a health risk when the fibers can be inhaled (when it's cut, sanded, or broken).
  • Removal and disposal may cost significantly more than siding containing no asbestos.
  • Some jurisdictions may require disclosure at the time of sale if the homeowner knows that the siding contains asbestos.