Fiber Cement Board Installation Guide

fiber board installtion stepsSurface Preparation

  • For best results, all surfaces must be clean down to the original substrate and free of any material or contaminant that may prevent adequate adhesion.
  • Air, caulk and surface temperatures must be above zero degrees (0˚F).
  • When installing fiber cement siding, refer to manufacturer’s recommendations for gap filling, to allow for expansion and contraction. (figure A)

Cartridge Preparation

  1. Cut sealant tip to proper size and angle 1/4” to 3/8” opening at approximately a 22.5 degree angle. (figure B) 
  2. Puncture inner seal with a clean object.
  3. Place cartridge in cartridge gun.

Product Application

  1. To ensure neat sealant lines use masking tape adjacent to joints. (figure C) 
  2. If joint depth exceeds 5/16”, use backing material. 
  3. Apply sealant into clean joint allowing for a 1/4” to 3/8” rounded bead. (figure D) 
  4. Always apply sealant in a bead form. DO NOT smear or wipe sealant to a thin consistency outside of joint or masked area. (figure E) 
  5. Once sealant is applied, DO NOT wipe over sealant bead with solvents. 
  6. Once product is dry to the touch and does not transfer, remove masking tape. (figure F)


  • Clean tools with isopropyl alcohol before sealant dries, following solvent vendor’s precautions. 
  • Once cured, sealant must be cut or scraped away.