When it gets wet the sheathing could swell and thicken up because of the moisture.
Osb or plywood for roof.
Despite also being susceptible to water damage lipinskiy says that.
Osb is made by combining glue resin and wood chips and pressing them into the shape of a plywood sheet then baking everything together.
It becomes soft and weak when it delaminates.
It is generally believed that osb is cheaper than plywood.
Today you can find osb in thickness from 7 16 to 1 1 8 for different applications from roof wall subfloor i joists and everything between.
For plywood it is like 5 to 10 more expensive.
It is true as the price of every osb board is around 15 20 per sheet 4 8 sizes.
Talking about plywood or osb for roofing you cannot miss the information of the cost.
Unfortunately an osb is less resistant to water compared to plywood.
Because of this manufacturing process osb is at least half the cost of cdx plywood.
This is one of the reasons why some people prefer using plywood for their roof or subfloor.
Plywood is better than osb for subfloors.
Thankfully there are osb materials today that are designed to be moisture resistant.
Osb panels can be manufactured in lengths up to 16 feet or sometimes even higher while plywood is generally limited to 8 to 10 feet.
While a sheet of plywood might be 5 to 7 plies thick a sheet of osb is made from as many as 50 strand layers packed and compressed into the same thickness.
The curb appeal of your home is lost because soon your shingles will start to misalign creating an eyesore on the top of your home.
However you might find that osb can better suit your needs than plywood for the roof.
New homes will usually see a few rainfalls before a roof is on and as noted above osb doesn t handle moisture well.
A few other downsides to plywood.
Both osb and plywood absolutely hate water lipinskiy mentions going on to say that the most important part regardless of which decking option you choose is that all penetration points on a roof are sealed.
Oriented strand board isn t plywood nor is it a type of particleboard fiberboard or wafer board and although it is a newcomer to a plywood dominated market its use for exterior sheathing is.
Osb boasts a more consistent density.
Because of its construction some manufacturers actually make larger sheets of osb.
University of massachusetts meets most building codes for roof and wall sheathing.
Despite its common use as such we don t recommend using osb for subfloors but that s really just for aesthetic reasons.
Earlier types of osb were known as waferboard which is now considered a sub standard version of oriented stand board.
It is often less expensive than cdx plywood because this manufacturing process doesn t require the same costly veneers found on the front and back of cdx plywood.