Give your walls a smooth and aesthetically pleasing finish
Drywall may be the go-to choice for most home construction and renovation projects these days, but some cases call for plaster. Whether you're restoring an old home or building from the ground up, knowing the different types of plaster that are available, and when to use each one, will help you choose the right material for your project.
Think of lime plaster as the original plaster. People have used lime plaster for millennia to build walls and construct homes. The material itself is made from lime, water, and sand, and occasionally, horse hair, which acts as a binder. If you're remodeling a home built before the early 1900s, you'll likely see strands of hair in the dried plaster.
Lime plaster is flexible and breathable, meaning it can release moisture, making it suitable for use in kitchen and bathroom walls. Its flexibility means it can move as a home settles, making it less likely to crack.
While lime plaster was the plaster of choice for centuries, it's now less commonly used compared to other types of plaster. It has a higher price point than gypsum plaster and takes longer to apply, making labor costs more expensive.
However, lime plaster is typically the material of choice when restoring older homes, particularly homes that originally used the material.
Best use for lime plaster: Restoring older homes, or giving a classic look to a new house.
Thanks to its lower cost, gypsum plaster is typically the plaster of choice in modern construction and renovation projects. This plaster is made from calcium sulfate dihydrate and is available in powdered form. Once mixed with water, the plasterer needs to work quickly to apply gypsum plaster. Otherwise, weak areas, or "cold joints" could form.
Gypsum plaster doesn't breathe as well as lime plaster so it's less suitable for use in older properties or in areas with high humidity levels, such as kitchens and bathrooms.
Best uses for gypsum plaster: Interior walls in modern homes (not bathrooms or kitchens).
Cement plaster consists of cement and sand, in place of either the gypsum or lime. It's quick-setting and thick, meaning you need to work fast when using it. You can use cement plaster on interior or exterior walls, but it typically has a rougher finish than gypsum or lime plaster, so it usually isn't ideal if you want a smooth wall.
Cement plaster is less flexible and breathable than either gypsum or lime plaster, too. The best use for it may be on the exterior walls of newer homes.
Best uses for cement plaster: Coating exterior walls.
Clay plaster uses clay as the base, mixed with sand and water. You can also add pigments to the clay plaster mix, eliminating the need to paint the walls when you're finished.
The plaster produces a rustic finish. Since there's no need to paint it, choosing clay plaster can release fewer volatile organic compounds (VOCs) into the home.
Clay absorbs water fairly readily, so the plaster isn't good for bathrooms and other high-humidity areas.
Best uses for clay plaster: Interior walls in modern homes.
Depending on the type of plaster used, it can be finished in several ways. Plaster finishes affect the texture, color, and overall appearance of the walls. For example, you may choose a plaster finish that creates a smooth, shiny wall or a rough, textured surface. Mixing different pigments into lime or clay plaster also increases your finishing options.
While there are many plaster finishing options available, two of the more popular finishes are Venetian and Tadelakt.
Venetian plaster is a type of finish for lime plaster that has added pigment, giving the walls a rich hue. A wax coating is typically applied as a finishing touch, adding a shimmer and sheen to the walls.
Some types of lime plaster have aggregates added. Tadelakt is lime plaster combined with olive soap. The addition of soap makes the resulting plaster waterproof, transforming it into an ideal pick for use in high-humidity spaces, such as shower stalls and bathrooms.
Before drywall came on the scene, plaster was the material of choice for interior walls. While drywall may be the more cost-effective choice in many cases, plaster may suit your aesthetic preferences better. Plaster walls also tend to last longer than drywall, and are more energy efficient, as plaster has superior insulating properties.
With its breathability and flexibility, lime plaster is among the most durable of all plaster types. It's also fire-resistant and has a proven track record, as people have been using it for thousands of years.
However, all plaster types will last for many years with the right care and treatment. Proper preparation and installation will also help ensure your plaster walls look great for as long as possible.
Whether you can repair or install plaster yourself depends on the project size and your tolerance for DIY projects. You may feel perfectly comfortable taking on a small plaster repair project, but prefer to leave a room restoration or renovation to a local plaster repair professional.
Since the project's end result, including its durability and appearance, depend on how well you prepare the wall and apply the plaster, you may want to let a professional take it on if you're not 100% confident.
You can put certain types of plaster over other types, but doing so isn't always the best idea. For example, putting a coat of gypsum over lime plaster is possible, but doing so will limit the lime plaster's breathability and potentially affect its performance.
Since cement plaster tends to leave a textured surface, no matter how much you smooth it, some people prefer to use gypsum plaster as a topcoat over cement plaster, creating a smoother surface.
