How to Find the Right Drywall Thickness for Walls and Ceilings

When it comes to soundproofing walls and ceilings, the best way to do it includes opening up the wall and working beneath the drywall. However, the drywall you replace the existing one with also plays a huge part. So today, I thought we should talk about which drywall thickness you should use for your walls and ceilings.

After writing an article on soundproofing walls and ceilings without removing drywall, a thought occurred to me. Namely, I realized that many people don’t know that soundproofing ceilings requires you to take the same steps as soundproofing a wall.

After all, they’re of similar construction, with drywall covering the frame underneath. Therefore, you should be able to follow the steps from my article on the best way to soundproof a wall and apply them to ceilings as well. These steps include:

  • Removing the existing drywall to get to the wall frame.
  • Filling the studs with soundproof insulation.
  • Installing MLV over the studs.
  • Attaching resilient channels to create a gap between the main construction and the drywall.
  • Finishing up with a layer of drywall or even a Green Glue drywall sandwich.
  • Seal the cracks with acoustic caulk.

If you’re interested in this method of soundproofing, you can check out more detailed instructions in the article I’ve linked. However, even then, you may come out confused about what kind of drywall you’re supposed to be using. So for the sake of clarity, I’ve decided to make this article a comprehensive guide to drywall.

In order to answer the original question about the thickness of the drywall we need for effective soundproofing, we should first understand what drywall is and what kinds of it exist.

Which type and thickness of drywall you should choose.

DRYWALL: A BRIEF GUIDE

First and foremost, let’s talk a little bit about what drywall is. These gypsum panels are made of calcium sulfate dihydrate and possibly some additives, depending on their purpose. Usually, this mix of materials is pushed between two thick sheets of paper. The facer and backer papers also serve to tell you which side of the drywall should be front-facing.

Now, some of you will know drywall by other names, such as plasterboard, sheetrock, gypsum, or gyp board. These are all essentially the same product. Still, you can check the chemical composition of the drywall you’re considering buying if the manufacturer disclosed that information.

The reason why we use drywall is mostly a matter of convenience. It’s easy to transport and apply and mostly cheap to replace. It’s certainly more affordable than having to put up lath and plaster, which we used to use before the 1930s. And it’s definitely better than having to fix concrete walls if they sustain damage.

Before you rush into buying any old drywall, you ought to consider what you’d like it to do. So let’s see what types of drywall exist.

THE 5 MAIN TYPES OF DRYWALL

As you start researching drywall, you’ll notice that there are about five main kinds. As I’ve mentioned, the main difference between these products is in the additives and the paper they use. So essentially, only the base and the general shape of the panels remain the same.

1. Regular Drywall

Regular drywall, otherwise known as white board, is the type of drywall you can use anywhere. This drywall is typically white on one side and brown on the other, with the light side facing the room. The main thing about regular drywall is that you shouldn’t expect too much of it in terms of durability. If you sustain water damage of any kind, it will definitely rot and grow mold and mildew.

So you should keep it somewhere you’re fairly certain mold won’t be able to get to. Fortunately, the next type of drywall endeavors to fix this vulnerability.

2. Mold-Resistant Drywall

Unlike regular drywall, mold-resistant products steer clear of the paper backing that makes the regular products more susceptible to mold growth. They also typically have a special coating layer that prevents living organisms from growing.

Although it’s a bit pricier than regular drywall, mold-resistant drywall is great for bedrooms and other rooms you spend a lot of time in. As you know, inhaling mold can lead to serious health consequences. So it’s best to ensure that you never come into contact with it at all.

Several products can be considered mold-resistant. For example, paperless drywall is a product that replaces paper with fiberglass. As such, it’s a bit harder to cut, but it’s much more mold-resistant than regular drywall.

Blue and purple drywall could also be dubbed mold-resistant. However, they have moisture-resistant properties as well, which are, in this case, different. So let’s see what using moisture-resistant drywall will get you.

3. Moisture-Resistant Drywall

When you ask around about moisture-resistant drywall, you’ll most likely get pointed toward products like Green Board. Still, even though it’s moisture-resistant, I wouldn’t count on it to withstand direct contact with water. That shouldn’t be too much of an issue if you apply the correct top coat or tiles correctly, though.

Basically, mold-resistant drywall wouldn’t do much good because it’s made to discourage growth, not block moisture. However, moisture-resistant drywall would be ideal for areas that see a lot of water and steam, such as the bathroom, basement, or the kitchen.

Essentially, this type of drywall has some type of waterproof barrier, although some individual products do it better than others. Purple drywall, for example, is great for walls and ceilings, and it should be fine even if it’s in direct contact with moisture. Additionally, Blue Board is also good for tiles, and it could even reduce noise.

All of these products are still gypsum-based, which isn’t ideal. If you want something truly water-resistant, you may want to consider using a cement board.

4. Fire-Resistant Drywall

The final type of drywall is commonly referred to as Type X drywall. This name essentially signifies that it has achieved at least a 1-hour fire resistance rating for a 5/8-inch drywall and a 45-minute resistance for a half-inch board. It’s great for stairwells and internal garages, and aside from being fire-resistant, it’s also so thick that it may provide some soundproofing. However, you may not need to go that far, since soundproof drywall already exists.

5. SOUNDPROOF DRYWALL

Whether or not soundproof drywall is effective is a complicated question. Some people swear by it, while others are more undecided — and I consider myself a part of the latter camp. Basically, this drywall is a bit thicker than standard ones, and it should technically work. It does have a higher sound transmission class in comparison to the other types of drywall.

As always, there’s a complicated answer to a complicated question. Soundproof drywall is somewhat effective when you install it correctly. However, I believe that any type of drywall could work to soundproof your room if you have the budget. The best technique I’ve found is the one I’ve mentioned at the beginning of the article.

Using Green Glue to create a flexible sound-absorbing layer between two layers of drywall could be the thing to do. It would definitely increase the thickness of the drywall, which is what you need in order to have effective soundproofing. So let’s see what drywall thicknesses we’re working with, anyway.

Drywall on the ceiling with a hole.

DRYWALL DIMENSIONS AND THICKNESS

Drywall dimensions are pretty standard, which makes all of this a bit easier. The boards are almost always 4 feet wide and can vary in length, according to the height of your walls. So expect to see a lot of 4 x 8 drywall, and even ones that are 9, 10, 12, and even 16 feet long.

When you’re working on putting drywall up on a ceiling, you may have to make some adjustments. However, you can still use these general dimensions to make your life slightly easier.

Also, there are some drywall boards that are wider than 4 feet, at 4.5 or 8-feet wide, although they’re few and far between. You’re much more likely to see smaller 2 x 2-foot piece of drywall, which is used for making repairs.

Drywall thickness usually moves from a quarter of an inch to 5/8 of an inch. In my opinion, using a quarter-inch drywall would be really pushing it. In fact, I can’t see it being effective at anything, let alone soundproofing, unless you’re layering it. Well — if you have curved walls, I suppose such a thin drywall would curve more easily.

However, in any other situation, I’d advise going thicker. Half an inch is pretty much the standard, and thicker ones are, as you’ve seen, the fire-resistant and the soundproof products. There are even drywall products that are 3/4 of an inch or up to an inch thick, although they have special uses.

THE IDEAL THICKNESS OF CEILING AND WALL DRYWALL

So after all of this, the question remains: what is the ideal drywall thickness for your walls and ceilings? Well, as I always say: the thicker the better. However, that doesn’t mean that you should head straight for the inch-thick drywall.

Instead, I suggest sticking to the industry standard of using a half-inch drywall for walls and 5/8-inch panels for the ceilings. You can even double up and use Green Glue in between. However, I certainly wouldn’t go any thinner than that.

Especially with the ceiling, your main concern is to make sure that the drywall doesn’t sag. The main way to do that is to use sturdy boards that won’t bend, which means that you should use thicker ones. However, since I don’t know each of your personal circumstances, it’s always best to consult a professional before starting a project.

And if your drywall just isn’t performing as you’d like it to be, you can always implement some cheap and easy ceiling soundproofing techniques. Or, you can simply use the same soundproofing methods you would use on your walls.

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