How to Apply Stucco With Cement Board to the Exterior of a House

Hang Backer Boards

• 1

  Fasten the first cement-based, concrete board panel with an edge butted against an inner corner or aligned with an outer corner of the house. Insert 3-inch galvanized decking screws approximately 1 inch in from each corner of the board with a power drill and Phillips head bit. Add more screws, spaced 6 inches apart, around the perimeter and throughout the field of the board.

• 2

  Butt the edge of the next board against the first, and fasten it to the house as before. Continue along and up the wall until the exterior is covered in all areas where full boards will fit.

• 3

  Measure from the last full board to an obstacle, corner or area where a smaller, cut board is needed.

• 4

  Measure a concrete board to match the space, and mark it with a pencil. Trim the board to fit the space with a rotary tool and masonry bit or wheel, and fasten it to the house. Repeat to cut boards to fill all gaps.

• 5

  Cover each seam between boards with mesh drywall seam tape, cutting off the excess tape with a utility knife.

Apply Stucco

• 6

  Fasten a paint mixing paddle to the power drill.

• 7

  Add the correct ratio of dry stucco mix to water in a bucket, based on the stucco manufacturer’s directions on the bag or container.

• 8

  Push the mixing paddle into the stucco mix, and blend the material at low speed until there are no more dry particles. Lift the paddle out of the mixture to spin off the excess stucco inside the bucket, then turn off the drill and set it aside.

• 9

  Mist the concrete board with water in a spray bottle where you will begin applying stucco, such as along the bottom edge or in a corner.

• 10

  Scoop up wet stucco mix on the edge of a flat trowel and spread a 3/8-inch-thick layer over the dampened board. Work across and up the wall, spreading the mixture to keep it even.

• 11

  Mix more stucco as you need it to continue working, and keep the concrete board damp by misting it.

• 12

  Drag the edge of a notched trowel across the stucco after you finish one section of a wall, but before the stucco dries. This provides a ridged surface for the second coat to grab.

• 13

  Let the stucco dry overnight.

• 14

  Mix more stucco as before, mist the wall and spread a 1/4-inch-thick layer over the rough first coat. Use a flat trowel to spread the stucco in short strokes to create peaks and valleys, or spread it evenly and add texture with a comb or any other tool that you desire.