Can You Plaster Over Green Board? (Explained)

Before drywalls were introduced, people used to plaster over walls. Plaster is a paste made by mixing gypsum and other ingredients with water. When applied on a surface, it hardens into a durable finish.

Plaster performs the same task as drywall. They smoothen the surface, only they are more durable and stronger than drywall.

Because of the many uses of plaster, you may consider applying it over the green board. Our article will address the possibility of plastering over green board and whether it will hold for very long.

green board drywall

Can You Plaster Over Green Board?

It is possible to plaster over a green board. However, you will need a plaster bonder to help the plaster adhere to the green board. It’s not a complicated project.

However, certain techniques must be followed to ensure the plaster doesn’t fall off prematurely. We will provide you with a detailed guide on plaster over a green board. But before doing that, we must define a green board.

Most of us are accustomed to the typical drywall used in living rooms and other parts of our homes. However, there is another type of drywall that is suitable for areas exposed to a lot of moisture and humidity. That type of drywall is known as the green board.

Green board is drywall designed to withstand a lot of moisture and humidity. Even though it’s not very popular these days, it still can come in handy for various home construction projects.

As the name suggests, one side of this drywall is green. It has this color so installers can know which side they should face the wall.

Its resistance to moisture and humidity makes the green board an excellent choice for high-moisture areas. However, it does have some limitations because it’s not waterproof.

Green board shouldn’t be exposed to a lot of water. That can lead to mold development and deterioration of the wall. Because of these reasons, do not use a green board on showers or kitchen sinks.

The best option for such a surface is a cement board. Besides the above, the green board is pretty easy to install. The method is the same as that of installing other types of drywall.

What Benefits Come from Plastering Over Green Board?

When you compare plaster and drywalls such as green board, they do the same job: to create a more appealing finish on top of walls.

That can leave you wondering why someone would want to plaster over green board in the first place. However, there are a couple of benefits that come from plastering over green board. They include;

When introducing plaster, we mentioned that it creates a more durable finish than drywall. Unlike the latter, which can be damaged by furniture, plaster is much stronger and resistant to impact.

You create a more robust wall by plastering over a surface like a green board. With plaster and green board, your wall can last for years without deterioration.

Plaster can also add some weatherproofing benefits to a green wall. If you want to use a green wall in an area that experiences a lot of moisture, you can add a waterproofing agent to the plaster.

Since plasters are not waterproof, a waterproofing agent can ensure its more resistant to moisture. Please note that the above shouldn’t lead you to use a green board in a shower.

Even though there will be some waterproofing benefits, excess water will sip through the plaster and lead to mold growth on the green board.

The other benefit of plastering green board is that it improves soundproofing. Whether it’s a residential or commercial property, you can always benefit from more soundproofing capabilities.

When you add a layer of plaster over the green board, less sound will be able to pass through. That can ensure the occupants of the premises are not affected by noises from outside and within the property.

How to Plaster Over Green Board?

Even though it’s a straightforward process, plastering over green board requires precision and patience. You also need to have a steady hand.

If you have never plastered a wall in the past, you will need to do some practice outdoors. It’s not difficult, and it’s something you can quickly get the hang of after several attempts.

Once you feel like you have what it takes, you can proceed to plaster over the green board.

Step 1 – Prepare the Green Board

Two scenarios can happen when you are plastering over a green board. One, you could be dealing with an old green board. Remember when we said green boards were popularly used a few years ago?

You could also be plastering over a new green board. If it’s new, you should tape the joints with an all-purpose joint compound.

If the green board has been there for some time, sand the surface and check if any holes need filling. Preparation is vital when plastering over a green board.

Step 2 – Apply a Plaster Bonder

The key ingredient when plastering over green board is to use a bonder. Without a bonder, the plaster will not adhere and won’t last long.

A green board won’t attach directly to plaster because of the paper substrate on the surface of the green board.

To prevent unwanted incidents in the future, get your hands on a decent plaster bonder and apply it according to the instructions provided by the manufacturer.

Step 3 – Layer the Base Coat of the Plaster

Having applied a plaster bonder, you will need to spread the first coat of plaster. As mentioned earlier, if it’s your first time, you will need to learn how to use a trowel and a hawk.

The first coat will act as the base. It should be relatively thin, around 3/8 inches thick. Make sure that you use lightweight plaster.

If it’s too heavy, it can fall off. If you are interested in improving the waterproofing of the green board, remember to add a waterproofing agent to your plaster mixture.

Step 4 – Spread a Finish Coat

With the plaster installed, you should wrap it up with a finish coat. Apply it the same way you did the base coat. But ensure the finish coat is slightly thinner.

You can create a textured finish with this coat. But that will require some plastering skills, which everyone may not have.

What Type of Plaster Should I Use on Green Board?

If you are stuck choosing the best type of plaster for green board, you should consider veneer plaster. It lasts longer than most plasters and can withstand dents and scratches. You can also use gypsum plaster which creates a matte finish.

Will the Green Color Show Through Plaster?

Unless you use extremely thin amounts of plaster, rarely will a green board show over plaster. Plaster is thicker than paint and other types of coating.

Therefore, when you plaster over green board, it will completely overshadow the green color. The only thing you will be left with is the color and finish of the plaster.

Should You Sand Over Green Board Before Plastering?

It’s a good idea to sand over the green board before plastering. Sanding creates a rough surface for the plaster to adhere to.

Even though the bonding agent will assist in adhesion, roughing the green board before plastering is a good idea. You can use sandpaper or an electric sander for sanding a green board.

The latter is more convenient to use when you are dealing with many walls that have been fitted with green boards.

How Long Will Plaster Last Over Green Board?

Plaster can last for years on green board if applied correctly and you use the right ingredients. Plastered drywall is a very durable finish that can withstand the test of time.

As long the combination of plaster and green board isn’t exposed to excess water, they should last very long. If you don’t use a bonding agent, the plaster will fall off when it begins curing.

Also, if you use heavy plaster, there is a high chance it will be too much for the bonding agent to stick to. As long as you follow our instructions, you have nothing to worry about.

Should You Hire an Expert Contractor to Plaster Over Green Board?

Plastering over green board is a project that requires some level of skill. Even though a newbie can easily pull off this project, if you have never plastered a surface, you can consider hiring professional help.

An expert contractor can correctly layer plaster over a green board. They can also create varying finished textures. This is something the average DIY enthusiast won’t be able to accomplish.

Also, plastering over green board is a labor-intensive process that will consume a significant amount of money.

There are many benefits of seeking professional help, but you will have to part with some cash. The contractor will charge labor fees, and you will also have to buy the plaster and bonding agent.

If you are unsure about your skills, it’s better to contract an expert instead of doing a sub-standard job. Through research, you should be able to find a professional plasterer who charges affordable rates.

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