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;
CLEARANCES and FLASHING
- 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.).