Plywood is incredibly popular; however, it’s also mysterious. If you’ve ever wondered what plywood is made of, then this article is for you. By the end of this guide, you’ll have a better understanding of what plywood is, how it’s manufactured, and what it can do for you.
Plywood consists of at least three layers or lamins of real wood. These layers are glued and pressed under high pressure.
MDF, OSB, and blockboard also fall under the term “plywood.” While these materials are not known as traditional plywood, they are worth understanding.
In the sections below, we will answer all your questions related to these materials.
Let’s jump right in!
Materials Used to Make Plywood
In this section, we’ll cover the different types of materials used to make plywood. Generally, plywood consists of wood! However, there are instances when plywoods will incorporate some non-wood finish, like countertops or bookshelves.
Let’s keep this simple. I’ll go over several types of plywoods and give you a brief idea of what they are made from and how they are used.
Note: MDF and OSB are not traditional plywood; however, we will cover those here as many people assume all these are “plywood.” Technically, anything with at least three layers is considered plywood.
Here’s a list of different types of plywood:
- Traditional plywood
- MDF board
- OSB board
- Blockboard plywood
Let’s discuss these below.
They make this plywood from layers of pine, fir, or spruce for softwoods. It also comes in hardwoods, including birch and maple. Higher grade plywood will have a smooth face and back laminated with oak or mahogany.
They rotate each grain from layer to layer – this ensures that no fibers run parallel to each other. Alternating the grain creates strength and resistance to warping.
Multi-laminated plywood can come in various plies. 3-ply is common; however, this won’t be as durable as five or seven-ply plywood.
This plywood can be used for sheathing on roofs and homes, making cabinets, and building bookshelves. It’s versatile and can be stained or painted.
Medium Density Fiberboard (MDF)
MDF board is made from fine sawdust that is glued and pressed. Unlike traditional plywood, there is no real grain to MDF. However, in some instances, MDF will be sandwiched between two lamins of hardwood, giving each side the appearance of real wood.
MDF has its pros and cons. Since it has no grain, it’s not as strong or as durable as plywood. The particulate nature of MDF makes it very susceptible to water. You don’t want to use this stuff outside.
MDF isn’t typically in any project that requires tough structural integrity.
Where MDF shines is indoor use, for things like cabinets and bookshelves. You can paint MDF easily. It is easy to smooth out the surface. However, it’s difficult to get a good stain on MDF, as it doesn’t have a true grain like wood.
Oriented Strand Board (OSB)
Think of OSB as a mix between plywood and MDF. We’ll talk about why.
Manufacturers make OSB from larges shavings of wood that are pressed and glued together. This is similar to MDF. However, OSB uses larger shavings instead of fine dust. And, OSB orients their shavings to create strength.
For this reason, OSB is stronger than MDF. OSB can be used for roofing a house or siding a home. OSB is not typically used for indoor projects where it can be easily seen. This is because OSB doesn’t have a clean edge, and it’s rather difficult to dress it up.
This plywood is often used for doors or projects where a very long piece of plywood is needed.
Blockboard is comprised of actual pieces (blocks) of wood that are glued together and pressed between two sheets of wood. The core of the blockboard is often softwood-based. This allows the board to be lighter than regular plywood.
Blockboard is known to have small gaps between the pressed boards. These gaps can make it difficult to use nails with blockboard as the nails tend to nestle themselves in the gaps, reducing holding strength.
This has been an overview of the different plywood types and the materials used to manufacture each kind. We will now focus more specifically on the first category of plywood, explaining the different grades and capabilities.
What are the Different Grades of Plywood?
While plywood may seem uniform and boring, there are many different types, each made differently. When we talk about what plywood is made of, we need to discuss the grades.
Some plywood is rated for indoor use, some for outdoor use. Some plywood is pressure treated to withstand rot. Others are not. In this section, we will go over the different plywood rating systems. This should keep you from getting lost the next time you’re plywood shopping.
Here’s a list of the grading systems:
- Exposure ratings
- Grade ratings
- Size ratings
Those are the three main categories. Now let’s go into each in more depth.
Plywood Exposure Ratings
Some plywood is built to withstand hurricanes and earthquakes – others are not. It’s vital to know which type you’re buying. Remember, use the right board for the right project.
Here are the different exposure guidelines:
- Exterior – this means the board can withstand severe weather.
- Exposure 1 – Waterproof, but not as durable for long-term outdoor use.
- Exposure 2 – Partially water-resistant, unlikely to withstand continued exposure.
- Interior – For indoor use, shouldn’t be exposed to rain and weather.
- Structural 1 – built to withstand earthquakes.
As you can see, there are many different exposure ratings. There may be some stores or areas that have things marked differently. If you are unsure, the best thing to do is ask a store associate to point you in the right direction.
Grade Surface Ratings for Plywood
Plywood is also rated used a letter grade. These grades will help you determine the overall value of the plywood.
The grades run from A to D.
A is the highest grade. This means that each side is sanded especially smooth and that the surface is free from knots and tear outs.
B is the next best. B is still smooth; however, you may have a few knots.
C is unsanded. Expect to see defects up to an inch and a half in size.
D is still unsanded. D grade will have even larger defects than C.
As you can tell, A and B grade plywood are for projects where the plywood will be seen, and C and D grade plywood are for projects that won’t be seen.
Sometimes, you might see plywood graded with two letters, like “AC.” This would indicate that one side of the plywood is smooth and finished, and the other side is rough.
Now let’s discuss the different sizes plywood comes in and a few tips for plywood shopping.
What Sizes Does Plywood Come in?
Plywood is often sold in sheets, four feet wide and eight feet long. Typically, this is as big as a sheet of plywood will be. However, hardware stores also sell ply in smaller sheets. Two feet by two feet is common, but you’ll find some even smaller.
How thick is plywood? Well, you can find it very thin, only one-ply, about an eighth of an inch. It’s also common to find three plies, about a quarter inch. And of course, five and seven plies – this can be anywhere from a half to three-quarters of an inch.
If plywood is much thicker than that, it becomes heavy and cumbersome to use.
Tip: though the smaller sheets of plywood appear cheaper and easier to handle, you may be better off buying a large sheet and having the hardware store cut it down for you. If you have a fair amount of projects, this can save you money in the long run.
What are the Best Projects from Plywood?
The nice thing about plywood – it can be used for a variety of things. You can use it for almost anything; however, you can’t use only plywood for all things.
For this reason, it’s vital you understand how your plywood is constructed, and how it’s designed to perform.
Here are some tips to follow when trying to select the best plywood for your project.
First, ask if you’re building an indoor or outdoor project. If your answer is yes, then you should stick with high-grade traditional plywood.
Second, are you using the plywood for structural support? If the answer is no, then you could consider using MDF. Remember, MDF is easy to cut and shape with a router.
Third, consider your bank account. While it’s always imported to use the most quality materials, you don’t want to go bankrupt trying to build a TV stand. Review this article and ask yourself which project is right for the job.
Plywood is made from different types of wood being compressed together and glued. Using the right plywood for your project is vital to ensure you get the job done properly.