Prone to swelling edges and telegraphing. “The major disadvantage of OSB is that if it gets exposed to significant amounts of water or moisture, the edges expand by up to 15% ... especially if they are cut edges. This swell will then telegraph onto the shingles or some flooring," according to PATH.
OSB is highly susceptible to water damage, is not as strong, is heavier, and more slippery than plywood. It is almost the same cost per sheet as the equivalent strength plywood. Plywood, per thickness, is stronger, water resistant, and lighter than OSB.
Oriented strand board (OSB) used in floors, roofs and walls, can grow mold in a week or less under the right conditions, causing ugly stains and a health hazard. Plywood â€'' thin, laminated sheets of wood pressed together with glue â€'' will separate and warp. (Warped wood is unsightly but structurally sound.)
Conclusions 1. The service life of OSB is indefinite (expect 50 years or longer) if it is used and protected properly. 2. OSB should not be used where it is permanently exposed to the outdoor environment unless panels are qualified as Exterior (e.g. siding) and recommended coating is periodically renewed.
Osb is stronger than plywood in shear. Shear values, through its thickness, are about 2 times greater than plywood. This is one of the reasons osb is used for webs of wooden I-joists. However, nail-holding ability controls performance in shear wall applications.
OSB can be manufactured into panels that are larger than plywood. OSB is more uniform, so there are fewer soft spots, such as those that can occur in plywood. OSB is less expensive than plywood. To build a typical 2,400-square foot home, OSB may cost $700 less than plywood.
Admittedly, OSB rots very quickly. Because of the speed at which it rots, Mark Parlee, a builder in Iowa who provided many of the photos shown here, calls OSB wall sheathing “vertical mulch.” But plenty of walls with plywood sheathing and board sheathing have also turned to oatmeal.
Contact with the ground must be avoided, as rising moisture can also damage them. Boards should ideally be stored in dry conditions beneath a roof.
In most cases, plywood is better. But, when panels are exposed to water and moisture, plywood is barely better than OSB. Both get damaged when exposed to water for long periods.
For residential construction, the building code requirement typically is for a rated sheathing panel of either OSB or plywood of 0.95 cm (3/8 in) thickness when sheathing is required, as for shear wall sections; however, the common practice is to use sheathing thicknesses greater than code, which is referred to as “ ...
Both plywood and OSB are effective choices for your subfloor needs, but OSB may be a better option for a garage than plywood. Plywood is a better option for projects that require a lot of cutting and molding, while OSB is a good option for those who need to cover areas where moisture exposure may be an issue.
Oriented strand board (OSB) is made of wood, but it is cement-bonded for extra durability. For this reason, termites aren't likely to eat it.
Strong Lifespan: The lifespans of engineered woods can often be a key drawback, but OSB panels boast a longer lifespan, offering 30 to 60 years of dependable performance. This further makes them a cost-effective choice, as they will not need to be replaced as often.
Oriented strand board (OSB) is a problem for resilient and wood flooring installations because of the nature of its construction. Traditional OSB is made from large chips of wood that will swell when exposed to humidity and moisture, causing the texture of the chip structure to show through on resilient floors.
Modern sheathing options include oriented strand board (OSB), plywood, foam board, gypsum, and structural fiberboard. These materials provide better moisture resistance, structural integrity, and energy efficiency compared to older options like plank and Celotex sheathing.
Since OSB is a cellulose-based material, most of the time it already contains mold spores and only requires moisture to trigger the growth process.
As ambient moisture changes, your OSB or plywood panels will expand and contract. When you butt the panels together tightly, there is no room for expansion and this can cause buckling in the panels. Leaving a 1/8-inch gap between panels allows them to expand and contract without buckling.
Using OSB Safely
When installing in vertical applications such as wall sheathing, you'll want to orient the smooth or stamped side facing out. The smooth side has a better moisture resistance and will ultimately provide better performance against weather.
OSB is the logical choice for walls, floors, and for general use within sheds and other garden buildings and structures.
Exterior paint will not only make your OSB attractive, but it also adds a layer of water resistance. So, the paint should be added before applying the waterproof so that the sealer can protect the topcoat. Note: if you need a more natural appearance, you can stain your OSB.
Also, by installing the stamps down, the rougher side of the panels is kept upward which helps with worker traction on the jobsite. However, structurally there is no difference in how the panel will perform whether the side with the grade stamps is installed up or down.
Typical Lifespan of OSB Outdoors
An untreated OSB board may last only a few months in harsh outdoor conditions. However, if it's sealed or coated, the lifespan can extend to several years. High-quality water-resistant OSB, when properly installed and maintained, can last up to 5–10 years in outdoor environments.
Like CDX plywood, solid wood sheathing planks also provide a very strong fastening surface and hold nails/screws better than OSB. Another benefit of diagonal tongue-and-groove sheathing is that the boards are much easier for smaller construction teams to work with compared to large OSB panels.
Wet wood rot tends to look discolored or darker than the roof around it. Dry wood rot tends to look like a fungal growth, and it makes the wood cracked and dry.