Plaster and lath wall systems are rarely utilized nowadays, save to repair existing walls or to restore ancient structures. After World War II, drywall, also known as plasterboard or wallboard, burst onto the scene and has stayed there ever since. Drywall is cheap, easy to work with, and provides good soundproofing for new constructions.
The main advantage of plaster over drywall is its texture. You can paint it any color you like or fill in any cracks or holes. Also, if you make a mistake painting it, you can always cover it up with another coat later. With drywall, you're pretty much stuck with white or gray, unless you want to spend a lot of money on specialty paper and paints.
Drywall is cheaper than plaster, but that's about all its got going for it. The laths inside the wall cavity that hold the tiles or boards together are usually made of wood or stainless steel, which can be difficult to remove if you want to change something about the wall surface later on.
There are several different types of plaster used today in building projects. Regular old-fashioned plaster is made by mixing water with calcium sulfate (whiting) and sand, which acts as a filler and thickener. You can add small amounts of other ingredients such as salt, sugar, or oil to help reduce cracking during drying.
Because plaster is considered a superior quality material than drywall in most cases, it should not be replaced with drywall. The only exception is if you're tearing down walls anyhow to rebuild the plumbing and electrical systems. Then you might as well go all the way and use solid wall materials.
Plaster walls are easier to work with because there's no tape or joint compound to deal with. The plaster can also be used to cover up defects in the drywall such as cracks or holes. This makes your house feel more like one giant piece instead of multiple smaller ones. Plaster walls are also able to hide small imperfections in the flooring or other surfaces below them. For these reasons, it's easy to see why so many home owners choose to have their plaster walls repaired rather than replaced with drywall.
If you're thinking about replacing your plaster walls with drywall, first understand that the job requires a lot of skill and expertise. Any amateur could do damage by cutting corners or using improper tools when removing old plaster from the walls and framing in new drywall. If you try to do this yourself, you could end up with damaged plaster or wood frames that need to be replaced too. Hiring a professional remodeler or builder will ensure the job is done right the first time around.
In such situation, replacing it with drywall makes sense. It's usually cheaper over time too.
Replacing plaster with drywall is usually a mistake because they are not designed to work together. Plaster is a porous material that allows water to seep through it by way of humidity. This is why most houses have some kind of moisture problem inside their walls. Drywall is a non-porous material so it doesn't allow for moisture to escape and therefore it can become moldy and rotten over time.
You should replace plaster with another material. It depends on what type of material you want to use but gypsum board is the easiest to work with because it's rigid and can be used as wall coverings. You should also try to find out why your house was built with plaster in the first place. There could be environmental reasons why it's not recommended anymore. For example, there are certain types of wood that aren't meant to be painted because they will rot if exposed to air pollution.
The best thing to do is to check with an architect or engineer who knows about building materials.