Difference Between Drywall and Plaster
The terms drywall and plaster are sometimes used interchangeably. For a skilled tradesman however, the differences between the two are like night and day. They require different skill sets, different tools, and knowledge of completely different materials. Before discussing the difference, let's explain two similarities, the purpose and basic materials. This will help us to see why the two are sometimes confused.
Purpose of Drywall and Plaster
The purpose of both drywall and plaster is similar. When constructing a building, metal or wooden studs are used to create a framework for the building, providing the basic structure. The stud framing can be likened to a skeleton. Drywall or plaster is used to cover the studs and create a foundation for the finished wall. Continuing with the illustration, drywall and plaster can be likened to the muscles and flesh of a building, filling out the frame and bringing it closer to the finished shape. Drywall and plaster are similar in that they both accomplish a similar purpose in building finished walls.
Gypsum as the Basic Material
Both drywall and plaster use gypsum as the basic material to span the distance between studs. From a very simplified point of view, drywall is simply preformed gypsum panels stood up on the walls whereas plaster is gypsum spread in place. You can liken the similarities to that of pre-formed concrete walls and poured-in-place concrete walls. However, the similarities between drywall and plaster stop there. What are the differences?
Differences Between Drywall and Plaster
Drywall is broken up into two separate trades, the Hangers and the Finishers (Finishers do the taping and finishing). Drywall Hangers cut drywall panels to size and fasten them to the studs. Drywall Finishers address the seams and joints between panels, ensuring the wall is perfectly smooth. Drywall Finishers in effect fill in the gaps that the Hangers left behind. On the other hand, plastering is one trade instead of two. Plasterers will usually install the lath, spread the base coat, and spread the finish coat to create a smooth wall.
Plasterers use a hawk and trowel to apply plaster whereas Drywall Finishers use a pan and knife. The techniques used with these tools are completely different. A Drywall Finisher cannot easily switch to using a hawk and trowel without training and extensive practice, and a pan and knife is a poor choice for spreading plaster. Similarly, a Plasterer cannot easily switch to using a pan and knife for drywall finishing. The tools and skill-sets are not interchangeable.
Drywall is quicker and easier to install than plaster. Plaster tradesmen are becoming more and more rare so it is sometimes difficult to find someone who is experienced with true plaster. Some Drywall Finishers claim to have experience with plaster but unless they are journeyman Plasterers, it is doubtful they can do anything more than simple patches in plaster. For these reasons, drywall is less expensive than plaster. When calculating the cost of drywall you must include the cost of the drywall panels themselves and not just the labor. However, even when including this, drywall comes turns out to be a cheaper alternative to plaster.
As a general rule, plaster is more durable than drywall. It has a harder surface and resists dents and scratches. There are types of drywall that claim to be extremely resistant to abuse. Some abuse resistant drywall comes close to the hardness and durability of plaster. Plaster is also better at resisting water damage. If soaked with a lot of water, it will crack and crumble. However, when it comes to incidental moisture from high humidity situations such as locker rooms, bathrooms, exterior stairwells, etc, plaster holds up better than even moisture resistant drywall.
From a high level view, plaster and drywall have some similarities. However, from a tradesman's point of view, plaster and drywall are completely different. A skilled Plasterer cannot pick up a pan and knife and do drywall finishing. In the same vein, a skilled Drywall Finisher cannot pick up a hawk and trowel and do plaster work. The skill-sets and tool-sets are not interchangeable.