How To Apply and Mix Stucco
What Is Stucco?
Stucco is a durable finish for exterior walls, usually composed of cement, sand, and lime, and applied while wet. One common use is stone casing a house. However, stucco can be used on interior walls as well, and is great for hanging wall ornaments or molding.
What Tools Are Needed?
You’ll need to purchase certain tools in order to stucco. A plasterer’s rake should be used for the scratch coats. Also, a strong, sturdy plastering trowel and several sizes of finishing trowels will be needed. Finally, a plasterer’s hawk (the board that holds the mortar) should be bought as well. For more detail on the tools needed, your local Lowes, Home Depot, or other hardware store should be able to help you.
How To Mix Stucco
Ready-mix stucco is usually the simplest way to go, however for those who want to make their own, the recipe is fairly easy.
You will need a wheelbarrow. Pour a five-gallon bucket of clean, fine sand into it. Add a gallon of hydrated lime. Hydrated lime has already been treated with water to form calcium hydroxide. It is powdery, so be careful not to breathe in the airborn dust.
About one quart of Portland cement should be added. The dry mixtures should be mixed with a hoe. This will help the consistency of the mix, as the components react differently when introduced to water.
A hose should be used to slowly add water. Turn the water off and mix everything together. To do this, use a pushing and pulling motion with your hoe. If the mixture is still powdery, add more water and keep mixing. Be careful not to add too much water though. When the mortar is the consistency of pudding, it is perfect for applying. Make sure to keep the mixture damp. If it starts to harden before you are finished, as a small amount of water and mix it again.
The Process
Start with a good, solid foundation material. Stucco adheres well to solid concrete or masonry wall. Make sure the area you are going to stucco is clean. This means that it is free of dirt, paint, and other material. Either wooden or metal slats (also called laths) or wire mesh should be applied to ensure that the stucco sticks and bonds properly with the wall. If done correctly, the additional layer will help prevent rotting and mildewing.
Dampening the wall right before the stucco is applied will help the stucco keep its moisture. Failure to do so can lead to the wall sucking the moisture out of the mix when it is applied. The base coat, also known as the scratch layer, should be applied about 3/8 inches thick.
While the scratch layer is still wet, diagonal, criss-crossed ridges should be made on the surface. This will make a track pad for the final layer. The scratch layer should dry for a few hours. Commonly, the basic layer is allowed to dry and another scratch layer is applied on top. Let each layer dry one – two days.
After the scratch layers have dried, a final top layer should be applied. This should be 1/8 inch thick, allowing the stucco to settle into the tracks.
Stucco can be painted (wet or dry) to match the interior color of any room. Also, while the final layer is still wet, you can make designs in it if you choose to. You’ll want to be careful, because a mistake now will be difficult to fix.
