Osb is made by combining glue resin and wood chips and pressing them into the shape of a plywood sheet then baking everything together.
Osb vs cdx roof sheathing.
Cdx plywood is produced by gluing together sheets of veneer with each layer being glued the opposite grain to the one below it.
Far too often i see osb sag between the trusses making your roof look wavy.
Cdx plywood is created by bundling layers of wood together.
Cdx is best for sub flooring.
2 perm 7 16 osb sheathing with a 5 perm wrb results in 1 43 perms.
That may not seem like a lot but when you are that close to the danger zone a 24 difference in permeability between final products is worthy of note.
In such places it does not get in contact with a lot of moisture which prevents it from getting damaged.
Each layer is placed on top of the other with the graining running in the opposite direction for the opposing layer.
Cdx and osb are used for almost similar things but because they have different features one is better applied in some tasks and the other one on other tasks.
It is also used for roof sheathing.
Before you can really grasp the different ways to use cdx plywood vs.
Compared to cdx oriented strand board osb is made very differently.
What is cdx plywood vs.
The major distinction between these categories is the actual construction of the sheets.
2 perm 7 16 osb sheathing with a 30 perm wrb results in 1 88 perms.
Wall sheathing and roofing.
One of the nice things about plywood is the variety of options you can buy.
Although osb typically offers a higher shear rating which adds rigidity to your structure.
Though manufacturer s claim they now coat the edges in water resistant seals to prevent this because boards are commonly cut to fit the structure there are still exposed edges.
Osb is also known for swelling along the edges when it gets wet which can cause an uneven subfloor and ghost lines on an asphalt roof shingles.
We have used osb for some time now we use 5 8 on the roof 7 16 on the sidewalls all with plywood clips for strength and proper exspansion gaps however 3 4 t g ulc or cdx for floors stands up to the weather while building.
My personal opinion is that osb performs well on the wall and floor but stick to cdx plywood on the roof.
Because of this manufacturing process osb is at least half the cost of cdx plywood.