Structo-Lite Cracking: Causes, Prevention, and Repair

Structo-Lite, produced by USG, is among the top basecoat plasters available today. Structo-Lite’s lightweight and excellent thermal conductivity make it a favorite material for both professional and do-it-yourself contractors.

Additionally, Structo-Lite basecoat plaster is very flexible and long-lasting. It can be used on a variety of surfaces, including metal lath, gypsum, concrete, and clay.

Like any plaster, Structo-Lite is prone to cracking despite its many remarkable features.

This post will list the typical reasons why Structo-Lite cracks and provide professional advice on how to avoid this issue.

Common Reasons For Cracking In Structo-Lite

• 1. Too Fast Drying of Structo-Lite

Not every kind of plaster is affected by this issue. Structo-Lite is prone to premature cracking if it is allowed to dry too quickly.

This frequently occurs when Structo-Lite is applied to a surface that draws moisture out of the plaster, such as brick or concrete.

You can take a few precautions when installing Structo-Lite to avoid it drying too quickly. Wetting the surface is one way to get started.

When you water a brick wall while plastering it, you stop the surface from drawing moisture from the Structo-Lite, which causes cracks to appear.

Using a bonding agent is another measure you can take to stop the Structo-Lite from cracking due to drying too quickly.

Improved adhesion will be encouraged by this bonding agent. You can be absolutely certain that the Structo-Lite won’t dry out too quickly if you use a bonding agent and moisten the walls prior to installation.

• 2. Fissures within the substrate

There is a significant likelihood that the walls of an old house you are plastering have cracks in them. Sadly, cracks on one surface—in this case, the Structo-Lite basecoat plaster—transfer readily to the subsequent surface.

If you’re plastering an old wall that has cracks in it, you have to fix them before you can put on the plaster. First things first, clean out any loose debris from the cracks.

Before applying caulk, make sure the area is rough. It’s a good idea to add reinforcements, like a metal lath, and then caulk the cracks if they’re too big and deep.

You can stop your wall cracks from spreading to the surface of your Structo-Lite basecoat plaster by using such a foundation.

• 3. Excessive Water Use

Overmixing Structo-Lite with water is another error that can cause it to become cracked. Structo-Lite’s molecular strength is diminished by a large amount of water. Applying it causes it to begin to crack.

USG advises combining three to three and a half gallons of water with a fifty-pound bag of Structo-Lite. It is better to aim for a stiff viscosity rather than one that runs too easily when you first start mixing.

It could be tempting to use a lot of water because it makes the paste spread more easily. However, doing so weakens the adhesive and increases the likelihood of cracks in the Structo-Lite.

Please adhere to the suggested mixture ratios in order to avoid experiencing this issue.

• 4. Using Structo-Lite in Thick Layers

Structo-Lite basecoat plaster should have a thickness of between 12 and 20 millimeters. Structo-Lite is a lightweight plaster, but as it dries, it begins to crack when applied in very thick layers.

Avoid using a lot of Structo-Lite during the installation process. Make sure not to overdo the number of coats, even if that is your intention.

• 5. Applying Structo-Lite Expired

You might be using an outdated version of Structo-Lite, which is another reason why it might be breaking. The majority of people are unaware that Structo-Lite has a very brief shelf life—roughly one to two years.

Take note of the dates on the bag if you’ve had some Structo-Lite stored for a while and want to use it to plaster your walls.

Using an expired Structo-Lite can result in a few different things. The Structo-Lite won’t set, to start. Second, because of its poor adhesion, dried Structo-Lite may start to crack.

Using an old bag of Structo-Lite might seem like a good way to save a few bucks, but it could get you into more trouble. Purchasing a fresh bag each time you have a plastering job is a safe practice.

Ensure that you utilize the entire quantity. If any is left, you can always give it to a relative or friend who needs it quickly for a project.

• 6. Foundation Movements

Structo-Lite doesn’t always get cracked while it’s drying. It can occasionally occur months or years later. A movement within the foundation is one of the common causes of Structo-Lite cracking a few months or years after installation.

Masonry components like ceilings and roofs can occasionally be subject to movement. While Structo-Lite is being installed, it may easily adapt to different shapes and designs, but once it dries, its flexibility is lost. As a result, the stress created by these movements causes cracks in the plaster.

Other than fixing the cracks, there isn’t much you can do to stop the foundation from moving.

• 7. The Structo-Lite Plaster Is Contracting

Structo-Lite, although an expensive plaster, is likewise prone to shrinking. And when that occurs, the plaster may soon start to fracture.

When you combine Structo-Lite with a lot of water, the shrinking gets worse. Structo-Lite will shrink less the drier it is. It is for this reason that whenever you mix it with water, you should always aim for a thicker consistency.

What Kinds Of Structo-Lite Cracks Are There?

After learning about the typical reasons why Structo-Lite cracks, let’s look at the various kinds of cracks that can occur on Structo-Lite plaster:

• Hairline cracks: On Structo-Lite, these are the smallest cracks that are possible. Frequently, they are less than 0.1mm.
• Fine cracks: These can be up to 1 mm wide and are a little larger.
• Easy-filled cracks: These are defined as cracks up to 5 mm wide. The most typical type of cracks in Structo-Lite plaster are easy-filled ones.
• Cracks in door and window frames: As the name implies, these cracks appear in the plaster next to the door and window frames. They can be up to 20 mm wide and are frequently larger.
• Structural Cracks: These cracks have a width greater than 25 mm. Most of the time, foundational movements are what lead to structural cracks.

The harder it will be to fix or repair, the larger the crack in your Structo-Lite plaster.

Can Structo-Lite Crack Due to Weather?

Your Structo-Lite plaster’s setting time is greatly influenced by the weather. USG states that Structo-Lite needs to be dried at about 55 degrees Fahrenheit. Anything in excess of that could lead to failure. The following are some ways that weather can cause Structo-Lite to break.

• The excess heat from the sun will hasten the drying process if the plastered wall or ceiling is exposed to direct sunlight. There will be surface cracks if the moisture evaporates too soon.
• There’s a good chance that excessive aeration during a windy installation will result in premature drying and eventual cracking of the Structo-Lite.
• Lastly, the Structo-Lite’s setting time will be prolonged if it is exposed to moisture from rain or high humidity. Small fissures could begin to appear.

How Can Structo-Lite Cracks Be Fixed?

In the unlikely event that you install Structo-Lite and discover some finish cracks, you can fill and fix them. Not every crack can be fixed, though. Structural cracks, for example, are frequently more serious and may require replacing with new Structo-Lite plaster.

You can fix hairline and easily-filled cracks on Structo-Lite by using caulk and adhesive filler. Before adding caulk with a bonding agent, be sure to remove any remaining dust.

After that, you can let the finish dry and smooth it out. Prior to fixing Structo-Lite cracks, you need to figure out what’s wrong with them. This is the most effective method to stop the issue from happening again.