The Ins and Outs of Cement Board Repair

When a construction project is being performed at your home or office, you will want to know all the terms the contractors referring to. This will give you a better idea of the service the contractor is providing and what you will be paying for. 

One term that you may not be familiar with is the ‘cement board’. These boards serve as backing for tile and it plays an essential role in tiling projects. 

This article will talk about cement boards and cement board repairs that may be necessary for your home. 

What is a Cement Board?

A cement board is a sheet made of cement and fibers that contain cellulose. It is typically 4’ by 8’ and ¼” inch to ½” inch thick. Its resistance to mold, mildew, and water makes it ideal for tile backing applications as tile is often located in damp areas. 

Cement boards can be used anywhere tile is installed to add strength to the structure.  It may be used on a floor, on the top of cabinets, or on walls to where tile installation is needed. It can be used in exterior or interior applications. 

Cement Board Repair

If you are getting a new tile in your home, the cement board does not necessarily have to be replaced. If it is not damaged, you can leave it as is. If there are small holes in it, you may be able to patch them yourself or call in a professional to do the job. If this is the case, these are the steps to take. 

  1. If holes are larger than ½ in diameter, use a carton knife or carbide tipped tool to cut a V-shaped groove behind the edges of the hole. This will help the patching compound to lock in behind the board. 
  2. Use a clean, damp sponge to wipe down the area. 
  3. Mix a small batch of thin-set mortar according to directions.
  4. Use a putty knife or trowel to fill the hole with the mortar. 

Here is the process if holes are larger than ½” thick. 

  1. Press a 2-inch-wide polymer-coated alkali-resistant fiberglass tape into the mortar. Overlap the edges with a half-inch of tape and trim away excess before proceeding. 
  2. Spread mortar to level the patch.
  3. Once dry, sand mortar and finish as desired.

For holes larger than a few inches, the following process is recommended. 

  1. Use a carton knife or carbide tip tool to cut the cement board to expose a stud on either side of the damaged area. 
  2. Use the knife to score and break a new piece of cement board to fit the hole. 
  3. Attach the new board to the stud using corrosion-resistant screws. Predrill the holes for easier installation. 
  4. Fill voids with a layer of mortar topped with fiberglass. Sand mortar until smooth and finish as desired. 

Note: It is best to call a professional for larger holes. 

Now that you know all about cement boards, you have the knowledge you need to oversee your construction project. Good luck getting the results you are looking for. 

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