The Pros and Cons of Plaster Walls

Plaster walls and lath are part of life in an older house. They can be beautiful or annoying, depending on the situation. Plaster repairs in Auckland was used as a wall covering for hundreds of years. However, it was not until the mid-1940s that it was replaced by drywall.

It doesn’t matter if it frustrates you or inspires. It is worth learning about plaster walls and the pros and cons of this historic wall covering.

Anatomy of Plaster Walls

Plaster walls are applied with a trowel and a hawk by skilled plasterers. Plaster walls can take up to a month to dry completely enough to permit painting.

Plaster was used over traditional wood lath. This was attached horizontally to the walls leaving 1/4 inch gaps between each piece of wood. This would allow the plaster to penetrate and form a “key”, which, once dried, would secure the plaster to the wall.

Other forms of lath were popularized later, such as metal lath, which is still used to support stucco applications. Rock lath was an ancestor to drywall. In the historical cusp year of the 1940s, rock lath was 2×8 sheets. The plaster was then applied to it.

Traditional plaster walls were covered with three coats. The scratch coat was a mixture of lime, sand and water that was applied to the lath approximately 1/4 to 3/8 inches thick. It was then scratched using hand tools to create a strong bond for the brown coat.

After the scratch coat had dried, the brown coat was applied the same way. It was trowelled to a thickness of 1/4 to 3/8 inches and then left to cure. The final coat was the skim, or finish coat. It was often skipped for lower-end projects.

The original skim coat was lime and water. In the early 20th century, gypsum became more popular as it was faster to cure than lime plasters.

Plaster Walls: The Pros

Surprised? There are many pros to plaster walls. If your plaster walls are in good shape, you can keep them there or repair them instead of ripping them down and replacing them with drywall.

The #1 Plaster Benefit is Stronger

A solid plaster wall is much stronger than drywall in terms of its tensile strength. Try sanding plaster cured plaster. It’s not going to happen. This strength is important to avoid any dents, nicks and dings that can occur with drywall.

Benefit #2 Plaster: Energy efficient

Why is thicker walls better? There are many reasons why a thicker wall is better, but the most important is energy efficiency. A traditional plaster wall is 7/8 inches thick, which is almost twice the thickness of most drywall. Plaster walls that are thicker than drywall have better thermal insulation, which can help you save money on your utilities.

Benefit #3 Better Sound Blocking

Plaster is thicker and harder than drywall, and it has a better sound attenuation because of its chemical composition. A wall twice as thick should be at least twice as sound-blocking. It is great for privacy but not for eavesdropping.

The Cons of Plaster Walls

Plaster walls are not perfect. There are many benefits to plaster walls, but they also have their downsides. It’s fair to share both sides.

Con #1 Poor WIFI Signals

These thick plaster walls are where WIFI and cell signals die. Even a small bungalow with plaster walls will not be able to use a basic wireless router. To get sufficient service in a plaster-walled home, you will need to upgrade to a mesh network like Google Wi-Fi. This is what I used with great success in my 1920’s house.

Con #2 Plaster Cracks

Plaster becomes more fragile as it ages, which means it is harder to cure. Cracks can form in ceilings and walls, especially in high-traffic areas and areas with unstable foundations. These cracks can also be caused by gravity and age. Plaster ceilings can be affected more by gravity because keys aren’t as effective as on walls. Also, foot traffic from upstairs can lead to plaster ceiling weakness.

Con #3 Hanging Things is harder

Plaster is stronger than usual, which means that it’s easier to drill or nail into. This makes decorating even more difficult. You can learn some tips to hang things on plaster walls. However, if plaster walls are present, putting a nail in them may prove futile.