How to Protect Magnesium Oxide Board from Water

07 Sep How to Protect Magnesium Oxide Board from Water

You can protect magnesium oxide board from water, but it requires extra effort. While this board can handle some moisture, it is not completely waterproof. If water penetrates, you might notice ‘weeping’ or salty drops on the surface. These signs indicate the board is absorbing water, which can lead to rusting of metal fasteners and even mold growth. Certain boards, such as those made with magnesium oxychloride, absorb more water than standard cement boards. To properly protect magnesium oxide board, you need to apply waterproofing methods and regularly inspect for any water intrusion.

Key Takeaways

• Magnesium oxide boards handle water better than most boards, but they are not totally waterproof and need more protection.

• Use sealants, coatings, and weather barriers to stop water from getting into the boards and causing harm.

• Seal the edges and seams well to keep water out and stop the board from getting weak.

• Keep boards in a dry, cool place and let them get used to the room before you install them to avoid damage.

• Check and take care of the boards often by cleaning and resealing them to keep them strong and free from mold.

Protect Magnesium Oxide Board

Water Resistance Overview

You may ask why magnesium oxide mgo boards work well in wet places. These boards are made from materials that help them resist water. They do not get bigger or bend when they get wet for a short time. Magnesium oxide board takes in about 37% less water than gypsum or cement boards. This makes it a good pick for bathroom and kitchen walls, or other damp rooms.

But, water resistance is not the same as being waterproof. If you use these boards outside, water can still cause trouble over time. Some boards have magnesium chloride binders. These can pull in water from the air. After a while, salty drops may show up on the board. People call these “crying boards.” This can also make the board weaker. Boards with magnesium sulfate binders last longer but cost more.

Tip: Always look at the binder type before putting magnesium oxide mgo boards on outside walls.

Here is a simple chart to show how these boards do:

Why Protection Matters

It is important to protect magnesium oxide, especially on outside walls or in places that get wet a lot. These boards fight water, but they are not fully waterproof. If water stays on them for a long time, it can make the board swell, hurt the surface, or make it weaker. If you do not protect it, your walls and the things behind them can get damaged.

When you protect magnesium oxide, your walls last longer and look nice. This matters most for outside walls, which get rain and damp air every day. Good protection also stops mold and keeps your home safe and healthy.

Methods to Protect Magnesium Oxide

Sealants and Coatings

You can keep magnesium oxide board safe from water by using sealants and coatings. These make a waterproof layer on the board. Silicone and polyurethane sealants are good choices. They stop water from soaking in and help the board stay strong. Pick a sealant made for magnesium oxide mgo boards or concrete. Spread the sealant in a thin, even layer. Let it dry all the way before using the board. Put on more sealant every few years, especially in wet rooms like kitchens and bathrooms. Some boards have water-repellent additives made during production. These help the board take in less water and last longer. You can also use acrylic primers and special paints for masonry. These coatings give extra waterproof protection.

Tip: Try the sealant or paint on a small spot first. This helps you see if it sticks well to the board.

Edge and Seam Sealing

Water can get in through edges and seams. You need to seal these spots to keep magnesium oxide safe. Clean and get the seams ready before sealing. Put fiberglass mesh tape over the joints to make them stronger. This tape helps stop cracks from forming. Cover the tape with joint compound and smooth the edges. Let it dry, then sand it for a flat finish. In bathrooms or other wet places, add a waterproof layer over the seams. Sand the edges before you put on caulk or trim. This helps the caulk stick better. Use a sealant that works with magnesium oxide board for best results. This keeps water out and helps the board stay strong.

• Clean and get seams ready before sealing.

• Use fiberglass mesh tape and joint compound.

• Add a waterproof layer in wet rooms.

• Sand edges before using caulk or trim.

• Put on more sealant every few years.

Weather Barriers

Use weather barriers when you put magnesium oxide board outside. This keeps the board safe from rain, wind, and sun. Magnesium oxide boards are not fully waterproof. You must cover them with other materials. Do not use them as the only outside layer. Use them as a base for rendering instead. Add water-repellent additives to the board for more protection. Chloride-based boards with soaking treatment work better outside. The board lets some moisture out, but it still needs a barrier to stop water from getting in.

Here is a table that shows the layers for outside protection:

Note: Weatherproofing helps your walls last longer and keeps water out.

Proper Storage

Storing magnesium oxide board the right way keeps it safe from water before you use it. Keep the boards inside in a cool, dry place. Stack them flat on wood or mats, not on the ground. Carry boards on their side to protect the edges and corners. Do not put heavy things on top of the boards. This stops them from bending. Let the boards sit in the room where you will use them for 48 hours. The best temperature is between 59°F and 77°F. Keep the boards away from damp air and sunlight. Use airtight boxes for small pieces. These steps stop water from getting in and keep the boards from breaking.

• Store inside in a cool, dry spot.

• Stack flat on wood or mats.

• Carry on the side to protect edges.

• Do not stack heavy things on top.

• Let boards get used to the room before use.

• Keep away from damp air and sunlight.

Alert: Never put magnesium oxide boards in the fridge. Water drops can form and cause clumping.

Identify Water-Resistant Boards

Certifications and Labels

You can find water-resistant magnesium oxide boards by checking for certifications and labels. These marks show that the board passed tests for moisture resistance and mold protection. Look for labels like ASTM G21, which means the board resists fungal growth. You may also see certifications for vapor permeability and dimensional stability. These features help the board stay strong in wet places.

Certifications give you confidence that the board will perform well in real life. When you follow the installation guidelines, these boards protect against mold, mildew, and water damage. You can use them in bathrooms, kitchens, and other damp rooms. The certifications match what you see in daily use. If you finish the board properly, it will not warp, swell, or delaminate after brief moisture exposure. Unlike plywood, which can break down when wet, magnesium oxide boards keep their shape and strength.

Tip: Always check the product label for water resistance ratings before you buy. Certified boards offer better protection and last longer.

Here is a quick list of what to look for:

• ASTM G21 fungal resistance

• Moisture absorption rate (look for 0.34% or less)

• Dimensional stability certification

• Mold and mildew resistance label

Simple Water Tests

You can do simple tests at home to check if your magnesium oxide board resists water. Start by placing a few drops of water on the surface. Watch to see if the water beads up or soaks in. If the water stays on top, the board has good resistance. If it soaks in quickly, you may need to add a sealant.

Try this easy test:

1. Place a small piece of the board on a flat surface.

2. Drop a teaspoon of water on it.

3. Wait for 10 minutes.

4. Check if the board changes color, swells, or feels soft.

If the board stays the same, it has strong water resistance. If you see swelling or soft spots, the board needs extra protection. You can also check the edges and seams, as these areas often let in water first.

Note: Even if your board passes the water test, always finish and seal it for the best results. This step keeps your walls safe and helps the board last longer.

Best Practices for Durability

Installation Tips

You can make your magnesium oxide board last longer by following smart installation steps. Start by letting the boards sit in the room for 48 hours before you install them. This helps the boards adjust to the humidity and stops them from warping. Always clean the surface and make sure it is dry and flat. If you install on exterior walls, use a moisture meter to check for dampness. Fill any cracks or holes with leveling compound and sand them smooth. Leave a small gap between the boards and the walls—about 6mm. This gap lets the boards expand and shrink without cracking.

When you fasten the boards, use corrosion-resistant screws. Do not overtighten them, or you might crack the board. After you attach the boards, seal all seams and edges. Use joint compound and fiberglass mesh tape to cover the seams. Sand the joints smooth, then apply a primer and a waterproof sealant. These steps keep water from getting into the walls and help prevent absorption. If you want to know how to keep mgo board from sweating, always seal the edges and use a good weather barrier on exterior walls. Good ventilation also helps stop moisture from building up in humid environments.

Tip: Never skip edge sealing or proper storage. These mistakes can lead to water damage and reduce durability.

Maintenance

You need to take care of your walls to keep them strong. Clean the surface with a mild detergent and a damp cloth. This stops dirt from breaking down the waterproof layer. Check your walls often, especially the joints and seams. Look for cracks, swelling, or signs of water. If you see damage, fix it right away with the right filler or sealant.

Inspect exterior walls more often, since they face rain and sun. If you want to know how to keep mgo board from sweating, make sure you keep the seams sealed and the surface coated. Store extra boards in a cool, dry place, stacked flat. Do not put heavy things on top. These steps help your walls last longer and keep their water resistance.

Alert: Skipping regular checks or using the wrong fasteners can cause rust and weaken your walls.

You can protect magnesium oxide board from water in a few ways. Use sealants to make a barrier against water. Seal the seams so water cannot get inside. Store the boards in dry places to keep them safe. Pick boards that resist moisture well. When you install, use screws that do not rust. Leave small gaps between boards so they do not crack. Clean the boards often and fix any problems fast. This stops damage before it gets worse.

Remember, magnesium oxide boards fight mold and moisture, but you still need to protect them to keep them strong for a long time.

FAQ

Can you paint magnesium oxide board to make it waterproof?

Yes, you can paint magnesium oxide board. Use a waterproof primer and paint for masonry or cement. This makes a shield on the board. Always test a small spot first to see if it sticks well.

How often should you reseal magnesium oxide board?

Reseal magnesium oxide board every two or three years. Check more often in wet places. Watch for damage or water marks. Reseal right away if you see any problems.

What happens if water gets behind the board?

Water behind the board can make it swell. Mold can grow, and fasteners can rust. Fix leaks fast. Always seal seams and edges to keep water out.

Can you use magnesium oxide board outside?

You can use magnesium oxide board outside, but add weather barriers and sealants. Do not use it as the only outside layer. Always follow the maker’s rules for outdoor use.

How do you fix water damage on magnesium oxide board?

First, dry the area all the way. Take out any damaged parts. Patch small spots with the right filler. Reseal the fixed area. For big damage, put in a new board.