How to Finish Cement Board for Paint [DIY Guide]

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Cement board is an excellent choice for home renovation. But you need to be extra careful with the finishing. The finishing means making it ready for the painting. 

How to finish cement board for paint?

Start by attaching the cement boards to the frame. Then, use the mesh tape on the gaps. Apply the quick-set cement on the boards and joints. Next, apply the waterproofing layers on the boards. After everything is done, do a quick inspection. So you can find out anything that you might’ve missed. 

We have sorted everything into 5 easy steps for you. Check out the details on how to do so. 

How to Finish Cement Board for Paint: 5 Effective Steps for a Great Finish

Cement board is more sturdy than any other board. It won’t even rot like wooden boards. If you don’t want to redo your walls soon, it’s an ideal option.

The general tools and material for wooden boards won’t be useful here. So, here’s a list of what you’ll need-

  • 3’x5’ Cement Boards
  • Quick-Set Cement
  • Self Adhesive Mesh Tape
  • Trowel
  • Corner Trowel
  • Paint Roller
  • Saw (with 6 teeth blades)
  • Blue Coated Cement Board Screws
  • Power Driver

Painting on a cement surface also requires different types of attention. Painting on metal surfaces or wood is totally different than this. 

Before painting on the cement board, we have something to offer. We summed up the crucial information into 5 steps. Here are the steps that will help you-

Step 1: Attach the Cement Boards to the Frame

Cement boards are generally available in two sizes. 3×5- foot and 4×8-foot panels. And their thickness is around ½ inch to ⅝ inch.

Most DIYers use the 3×5 footboards as they’re easier to handle. However, you’re free to choose the one you prefer. It mostly depends on where the project is taking place. 

Grab the boards and attach them to the frame. You might need to cut the boards to a certain size first. For that, you’ll need a saw with a six teeth blade. 

Make sure that the blade tips are faced counterclockwise. Or else you’ll fail to cut the boards.

To keep them in place, there’s a special type of screw with a blue coating. They’re known as cement screws.

Where people compare among different board screws, cement screws stand at the top. These screws have a dangerously sharp end and tough build. After all, they need to go through cement.

Remember to use a screw for every 12 inches of the board. This will ensure equal distribution of the board’s weight. So, your board won’t be out of proportion any soon. 

Step 2: Use the Mesh Tape

After attaching the boards to the wall, you’ll see a gap between the joints. You can’t keep those gaps open like that. 

The solution is applying self-adhesive mesh tape. Use the mesh tape over the joints. One layer of it is enough. Make sure you don’t over tape or it’ll portray a horrible finish.  

Also, the corners of the cement boards need a smooth finishing. So, apply the mesh tape on the corners too. A corner trowel might be of great help in this case. 

Step 3: Apply Quick Set Cement

It’s time to apply quick-set cement on the surface of the cement board. Most people use cement on the joints. But you can use it all over the boards if you wish. 

Take a bucket and mix the quick set in it. The mixture should be thick and slurry. Apply it to the surface using a trowel right after it’s ready. 

Prioritize the taped areas most. The goal is to get the cement in the fiber of the mesh tape. It’ll create a surface where the waterproofing membrane can bond to. 

Let it air dry after applying. It will take about 20-30 mins to set. Until it doesn’t completely set in place, don’t move on to the next step.

Step 4: Time for Water Proofing

Most people use cement boards for the shower room or washroom.  So, waterproofing is a must if it’s in these areas. Plus, there’s nothing to lose if you apply the waterproofing membrane all over the house.

So, layer on the waterproofing membrane and let it set. Start the layers from the base. The more waterproofing you leave on the boards, the better. 

If you’re constructing a sauna, always add an extra layer of waterproofing. 

You can use a roller to save up time and ensure the expansion of the product. For the shower, covering 4 feet of the board might be enough for you. 

However, any areas vulnerable to water should be your target. The goal is to not let the water penetrate through the wall. 

A single coating might not be enough for a shower. So, after the first coating, let it sit for a few hours. Check the surface with your finger before using the second coat. 

The usage of the waterproofing membrane depends on your budget too. Using most of the budget on waterproofing is not ideal. You can’t just use $1000 on the waterproofing on a $500 project. 

However, we have a few favorites when it comes to waterproofing membranes. Here’s a list of them-

Our Recommended ProductFeatures

Waterproofing membranes have been in the market for 10-12 years. So, you won’t have an issue finding it.

In some states, waterproofing is part of the building code. So check the building codes as they’re quite helpful in maintaining safety and costs

Step 5: Do a Proper Inspection

After the waterproofing, you need to apply the paint. Before that, you should check your work one last time. 

Check all the screws to ensure the well-being of the boards. The joints also need your attention. Make sure there’s no gap. 

Moreover, make sure you don’t miss any area while applying a quick set and waterproofing. Also, everything should be properly dried and set before painting.

FAQs

Question: What kind of paint do you use on the cement board?
Answer: Acrylic paint is the most suitable paint for cement boards. It’s permanent on the wall and helps you deal with the water. Even the surface can be cleaned using soap and water later on. 

Question: Can you use a joint compound on a cement board?
Answer: Yes, you can use the joint compound on a cement board. However, it’s completely fine as long as it’s a dry area. Even using it above your shower is fine. But DO NOT use it IN your shower. It won’t respond well with water.

Question: How do you attach cement boards to steel studs?
Answer: Cement boards do go with steel studs. First, you need to place the board in place. Then, use metal screws to attach the board to the metal framing. Make sure that they are tight and stable with the studs. A power driver might make it a lot easier for you. 

Conclusion

And that’s all we had on how to finish cement boards for paint. If you can pull it off as we said, the project might be worth your efforts.  

Don’t forget to keep your safety in mind. The blades and screws are pretty sharp. So, take precautions before you start. 

However, if you ever face any issues, contact the professionals.  They might finish the project more efficiently, in exchange for some cash.

Scott Kelly