Grades of Plywood
As you have understood from the above paragraph, A, B, C, D are grades of plywood commonly used. When you have a look at the plywood, you will find the letter grades are printed in pairs. These plywood grades explained here, will help you understand their hidden meaning. This means, if one side is printed with A and the other side with C, it indicates that the plywood has a well finished front side and a slightly unfinished back side. Construction grade plywood is graded as C-D and called CDX plywood. The best way to explain grades of plywood is by understanding the types of plywood. Let us have a look at the four basic types of plywood.
Types of Plywood
There are different plywood sizes and types available in the market used for different purposes. The explanation on types of plywood will help you understand the use of these woods in home construction better.
Interior Plywood
The interior plywood is available in different grades and the common grades are A-C, B-D, etc. Interior plywood is used for construction within the house. They cannot be exposed to moisture and are bonded with agents that give away when exposed to the elements of nature. Thus, these plywood should be kept away from wet areas and never kept outdoors.
Structural Plywood
Structural plywood is available in grades such as C-D and D-D only. These are rough plywood pieces that are used for cement forms. They are glued together with adhesives that hold the layer firmly. It can be used in any area where you do not mind the looks of the rough plywood.
Exterior Plywood
The grades of plywood in case of exterior are A-C, B-C and CDX. Exterior plywood is glued together with adhesives that are meant to survive in wet or moist areas. They are used in the construction of a house exterior region or outdoor furniture.
Marine Plywood
The marine plywood is only available in A-A grade. It is the strongest, toughest and the best quality plywood you can ever find. It is glued together with superior quality adhesives that bonds tightly and is resistant to water. It has both sides finished as it comes in A-A quality. It is used for construction of outdoor furniture, and other areas where you want the plywood to look good as well as remain weather resistant.
Marking of Grades
Plywood is generally available in 4'x8' sheet and is cut into a square board. The thickness of plywood normally used is 1/8", 1/4", 1/2", and 3/4". The 1/8" and 1/4" plywood is used for making hard covered flats. 1/2" plywood is used for building furniture parts, boxes and props. It is lighter as well as cheaper than 3/4" plywood. Lastly, 3/4" plywood is used to make covering platforms as it is very strong type of plywood.
Plywood Grades Chart
The following plywood grades explained with the help of the chart will make things regarding the type and their uses clearer.
| Interior Plywood Grades | |||
| Plywood Grade | Front Side | Back Side | Inner Plies |
| Underlay | C Plugged | D | C, D |
| C-D | C | D | D |
| B-D | B | D | D |
| A-D | A | D | D |
| A-B | A | B | D |
| A-A | A | A | A |
Interior Plywood Grades and Their Uses:
Underlay: This plywood is used as an underlay for carpets as well as tiles on an uneven sub floor.
C-D: This plywood is used for structural as well as sheathing of sub floors and shuttering.
B-D: This is a utility grade plywood with only one side that can be painted.
A-D: This is a finish grade plywood used for making furniture.
A-B: This plywood has one face that is finished grade and the back face has no voids and is very smooth.
A-A: This is finish grade plywood on both sides used for making domestic furniture, cabinet doors, etc.
| Exterior Plywood Grades | |||
| Plywood Grade | Front Side | Back Side | Inner Plies |
| C-C | C | C | C |
| C-C Plugged | C Plugged | C | C |
| B-C | B | C | C |
| A-C | A | C | C |
| A-B | A | B | C |
| A-A | A | A | C |
Exterior Plywood Grades and Their Uses:
C-C: This plywood is used for rough building work and shuttering. The unsanded C-C grade can withstand heavy exposure to weather.
C-C Plugged: This plywood is used for backing tiles and wall coverings. It can also be used for high performance coatings.
B-C: This plywood is used for landscape and general building uses like fences and shuttering. It is also used for base coatings.
A-C: These are for soffits and facias as well as used for base coatings.
A-B: This has just one side as finished grade.
A-A: This has both sides finished grade and is used for making the structure look more beautiful.
The plywood grades explained in the above paragraphs and charts must have helped you know all about the four types of plywood. Now you will be able to understand what an Exterior/Grade C-C plywood means and its uses. The interior plywood sheet needs to be used for construction of furniture within the house and exterior is meant for outdoor use. Hope you have been able to understand the grades of plywood better from the above paragraphs.