How to Repair a Hairline Crack in a Soffit Board

Exterior-Grade Caulk

• 1

  Set up an extension ladder to reach the hairline crack in the soffit board.

• 2

  Scrub the surface of the hairline crack with a dry scrub brush to remove layers of dirt. Spray a grease-fighting detergent onto a rag and wipe the entire length of the crack.

• 3

  Cut the pointed end of a tube of exterior-grade caulk with a utility knife. Pierce the inner skin of the caulking tube with a nail.

• 4

  Place the tube of exterior-grade caulking material into a caulking gun.

• 5

  Squeeze the trigger while moving the tip of the tube along the hairline crack, running a bead of caulking 1 inch before the start of the crack to 1 inch past the end of the crack.

• 6

  Wet a latex-gloved finger and move your finger over the caulk while pressing it into the hairline crack.

Two-Part Epoxy Repair Putty

• 7

  Lean an extension ladder onto the side of the house under the hairline crack in the soffit board.

• 8

  Brush away dirt with a dry scrub brush. Spray a grease-fighting detergent on a rag and wipe the crack.

• 9

  Knead two-part epoxy repair putty until it is soft and pliable. Roll the putty between the palms of your hands to make a thin line of putty.

• 10

  Place the putty over the crack. You may have to make several lines to accommodate the length of the hairline crack. Overlap each line of putty by 1/4 inch. Begin the line of putty 1 inch before the start of the crack and finish 1 inch past the crack.

• 11

  Hold a putty knife at a low angle to the soffit board. Press the epoxy putty into the hairline crack tightly, allowing the putty to remain at least 1/4 inch on each side of the crack. Let the repair putty dry for one hour. Sand the repair putty flush with the soffit board with 80-grit sandpaper.