How to Finish Cement Board for Paint?

For exterior design or home renovation, a cement board is a great choice. This is one kind of fiber cement that is excellent backing for floors, tiles, and walls. While using cement board, it needs to be painted. But before painting cement boards, they require careful finishing. Only after a great finishing, you can paint the cement board properly. So, knowing ‘how to finish cement board for paint’ is definitely important.

how to finish cement board for paint
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The cement board is highly resistant to water and mold. So, it is also beneficial for interior uses where moisture content is high. It decreases the damage of sheathing from water. Finishing the cement board is the first and foremost thing to do before painting cement board. So, stick to us to know the whole procedure.

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How to Finish Cement Board for Paint?

Painting cement board becomes easier once finishing is done properly. When the cement board is finished it can soak up the paint adhesive within its pores and improves painting quality. The paint also lasts longer no matter how rough the weather is.

Many people out there ask for cement boards instead of wooden boards because they are way sturdier. Also, cement boards will never rot or damage like wooden or other boards. Hence, for a lifetime benefit, cement board is a good choice.

Nonetheless, finishing cement board for paint is easy if you follow the procedure and its steps one by one. Let’s make it easy for you and describe the steps below.

Required Materials

Finishing cement boards requires different types of materials, unlike the ones that are used for wooden boards. Let’s see a list of the materials.

  • Cement boards and frame
  • Tape measure
  • Quick-set cement
  • Saw
  • Corner trowel
  • Paint roller
  • Screw or power driver
  • Screws for cement board

These are the materials needed for finishing the project of cement board. So, you can already predict that it is going to be a lot more different than the metal finishing or wood finishing.

Step 1: Cement Board Attachment to the Frame

This is the first and foremost step of this whole process. There are, however, two different sizes of cement boards are available. One comes with the size 3X5 feet and the other with 4X8 feet. Also, they come with a thickness from 1/2-inch to 5/8-inch.

However, if you are a DIYer, selecting cement boards of 3X5’ will be wise. It is because the size is easy to handle and work with. A larger construction site requires other sizes of cement boards. So, it is better to choose according to your need. Now, to attach the board to the frames, do the following.

  • To attach the cement boards properly to the frame, you need to cut them in a proper size first. A circular saw will be better for this job. With its six teeth blade, the saw can cut the board precisely.
  • Try to run the saw when the tips of the blade are faced anticlockwise. This will enable easy cutting of the cement boards.
  • When you place the cement board to a frame you need to screw it. There are cement screws available in the market that comes with a coating of blue color. These are some of the special screws specifically meant for this purpose. Because of their tough construction and evil sharpness, the screws stand out from all other board screws. It is so obvious especially when you are dealing with cement boards.
  • For equal distribution and proper attachment, set the screws after every 12-inch of the cement board. In this way, the screws can hold the board with equal force. So, the attachment will be long-lasting as well.

Also Read: Top Paint Sprayers for Chalk Paint

Step 2: Fill the Gaps

When you attach two or more cement boards to the wall, there creates a gap between the two boards. You need to fill the gaps between the joints otherwise the finishing won’t look good.

  • In this situation applying mesh tape is recommended. These are self-adhesive mesh tapes and work great with only one layer.
  • Put the tape over the board joints firmly without overlapping them. Overlapping the tape can result in an awful finish.

Here is a cement board tape: FibaTape FDW8436-U Cement Board Tape (See Price)

Step 3: Don’t Forget the Corners

The corners of the board also require filling. Otherwise, you won’t get a perfect finish. You can do it with the mesh tape too like the previous way. Nonetheless, with the help of a corner trowel, you can do this step quite easily.

Step 4: Time to Put in Quick-set Cement

This is one of the crucial steps of this process. Now, applying cement mostly depends on your preference. There are people who want to use cement only on the joints. Again, some want it all over the boards. Both will work well if you do the step carefully.

  • To make a mixture with the quick set, get a bucket first. Then make the mixture in a way that it makes a slurry yet thick consistency.
  • When the mixture is fully ready, you need to apply it right away. Use a trowel to put the mixture on the surface.
  • Carefully apply it to the areas where mesh tape is applied. The finishing won’t result as you have expected if you are not careful with the taped areas.
  • Make sure the mesh tape fibers get the cement in them properly.

Step 5: Let it Dry

Let the quick-set cement dry after applying it. It should not take longer than 20 or 30 minutes to set properly. Indeed, it will be unwise if you get started with the next step without letting it dry and set completely.

Step 6: Get to the Water Proofing Part

Waterproofing is highly recommended especially when you are up to use the cement boards in your washroom or shower room.

At least, till 4 feet of the wall should be covered. Therefore, you need to apply a layer of the waterproofing membrane.

  • Set the layer on the cement board and start it from the base. Let the layers set again. Adding more waterproofing layers will bring better results.
  • To expand the waterproofing layer, use a paint roller. It will save both time and the product. Nonetheless, inspect carefully what areas are most vulnerable to water. Cover those areas finely.
  • However, for the shower room since one layer of membrane is not enough, you need to apply the second coating technically. You just cannot go for a second coating right after the first coating. Let the first coating sit and dry first for at least a few hours.
  • Before applying the second coat, check the first layer by tapping gently with your finger.

However, the durability of the waterproofing membrane depends on the budget you have kept for it. There are some of the best waterproofing membranes available in the market within budget-friendly rates.

Step 7: Lastly, Inspect Properly

When you are done with waterproofing, inspect properly if the layer has sat properly. Also, check if the screws are on point and tightly screwed. Check if the gaps are filled perfectly. Again, check if you have not missed any place while applying the quick set. If everything is okay, dried, and fully set, then you are done with finishing and you can start painting over it.

What Kind of Paint Do You Use on Fiber Cement Board?

In most cases, acrylic paint for cement boards is used. This paint is suitable but only for dry areas. But in where there are chances of getting wet, you should not use this paint. Mostly, 100% acrylic is the best exterior paint for cement boards. Moreover, for painting cement board sidings, this paint is ideal as well.

Final Words

So, now you can presume the whole procedure of how to finish cement boards for paint is an easy task. Even if you are an average DIYer, you can do it once you go through the steps. However, it is important to wear safety gear before you get started with it.

Since you need to deal with sharp blades and screws, taking precautions is a must. Also, if you are dealing with a major project, better call a professional instead.