OSB (oriented strand board) is an excellent alternative to plywood flooring for sheathing walls, floor underlayment, and other projects. However, it can swell when exposed to moisture, and it is important to make sure it is sealed correctly during construction.
It is also treated with chemicals, including formaldehyde, which can cause off-gassing and may be a concern for individuals who are chemically sensitive.
Cost
OSB is an engineered wood product that uses thin strands of wood in crosshatch orientation to form panels. It is produced in large plants across the United States and Canada. It is used for structural and non-structural purposes, including wall sheathing and floor and roof sheathing. It is also used as a web material for prefabricated I-joists and as the skin material for structural insulated panels. Other uses for this type of wood are furniture frames, shipping pallets, and industrial tabletops.
The strands of wood in OSB are arranged and mixed with adhesives, then pressed into sheets that can be cut to various sizes. Most BC-produced OSB is sheathing grade, which is rated to resist wind and seismic loads. It is a cheaper alternative to plywood for construction projects.
Because it has a similar structure to natural wood, sheathing grade OSB can withstand more pressure than normal lumber. However, it has lower bending strength than plywood. Using sheathing grade OSB in a project that will see high levels of activity can result in it being more likely to delaminate or separate.
OSB has a lot of advantages over other types of building materials, including its low cost. It is more environmentally friendly than other kinds of plywood because it is made from smaller-diameter trees. Moreover, it can be treated with borate compounds that make it toxic to termites and wood-boring beetles.
However, the downside of OSB is that it can swell when it comes into contact with water. The glue and resin in OSB repel moisture, but it can swell like a sponge once it becomes saturated. This can cause damage to other materials, such as flooring or drywall.
Because of its swollen edges, it is difficult to nail or screw into OSB. This can be a problem when you are trying to install a ceiling in your garage. The best way to work around this is to use a fire-rated OSB. The only disadvantage of this is that it will be more expensive than standard OSB. Nevertheless, this type of ceiling is ideal for those who don’t conduct welding or other flame-inducing activities in their garage.
Durability
The durability of OSB depends on what kind of wood is used to make it. For example, the material will decay more quickly if made from poplar or aspen but is more resistant to decay when made from redwood or pine. It also requires more frequent sanding and finishing than plywood, which can cause it to wear down faster.
OSB is made from compressed layers of wood strands, or flakes, that are placed together and then bonded with resin under high heat and pressure. The process makes the wood stronger and more durable than traditional lumber, but it does not require harvesting large trees. Instead, the strands can be harvested from smaller-diameter trees that grow more rapidly and can be farmed. This makes the material a greener choice than standard plywood, which must use larger-diameter trees that cannot be farmed.
In addition, oriented strand board is much lighter than plywood. This is a major benefit when it comes to transporting the material and installing it in the building. It also reduces the weight of the roof or wall, which cuts down on energy costs.
However, many people don’t like the look of OSB. It has a rough texture and can have a slightly blotchy appearance that doesn’t blend well with other building materials. It is also typically treated with urea formaldehyde, which some people find to be toxic.
Oriented strand board has been around for a while but is not as well-established as plywood. Its track record is still relatively short, but it has proven to be strong and long-lasting in buildings. It can be treated with fire retardants and other chemicals to improve its resistance to fire, water, and insects.
One disadvantage of OSB is that it can swell more easily than plywood does when exposed to water. This swell can uplift the tiles or other flooring that is laid on it, and it may also cause nails and screws to become loose. This can be problematic, but it is easily remedied by using waterproofing on the material.
Moisture Retention
While OSB is much stronger than plywood, it still has some drawbacks when compared to other engineered wood products. For one, it can retain moisture, leading to swelling and rotting over time. It can also be a fire hazard, particularly if it is exposed to sparks. It can also be difficult to work with due to its rough texture. For these reasons, many builders choose to use drywall instead of OSB in ceiling construction.
Unlike plywood, which consists of large veneers, OSB is made up of strands and smaller pieces of wood pressed together into a single sheet. This means that there is a lower chance of knots or holes in the material. It can also be more structurally consistent than plywood. This is especially true in the case of OSB, which has been glued with soy-based resins, which are much more water-resistant than traditional plywood glues.
However, because the strands are denser than plywood, it is more susceptible to decay. This is especially true if the strands are made from softwoods, such as aspen or poplar. In fact, a class-action lawsuit against Louisiana-Pacific forced the company to pay $375 million to 75,000 homeowners who complained of their OSB boards decaying in their homes.
Another disadvantage of OSB is that it can release formaldehyde into the air when exposed to water or humidity. This can lead to respiratory problems, skin and eye irritation, and nausea. These problems can be minimized by using low-formaldehyde or formaldehyde-free OSB, working in a well-ventilated area, and following all other safety protocols when working with building materials.
While OSB can be used in various applications, it is unsuitable for exterior buildings. It is not waterproof and can withstand a light drizzle without damage. Plywood, on the other hand, can be a good choice for exterior applications. It can be treated to make it more waterproof and more flexible than OSB, allowing it to flex slightly as temperatures and humidity change. This flexibility makes it better suited for curved walls and roofs than OSB.
Swelling
The same resins that help to hold strands of wood together and make OSB rigid also cause it to swell if exposed to moisture. This means that if you are going to use OSB in your construction project, it is important to protect the panels from water during sheathing or other types of work on your structure. This is why it is a good idea to leave a 1/8-inch gap between the panels, as the expansion caused by moisture can result in damage.
The sheathing grade of OSB is typically made from smaller-diameter trees used for dimensional lumber, so it does not negatively impact the environment as plywood does. However, the fact that it is made from strands of low-density wood rather than whole pieces of solid wood makes it less flexible than plywood and can lead to buckling if it is subjected to excessive pressure. This can be overcome by installing OSB over a vapour barrier.
Another drawback to using OSB is that it does not hold nails as well as plywood, so it can be more difficult to install your roof. This is because the wood strands are not arranged in even rows. Also, it is not as resistant to warping and distortion if the weather is very hot or cold, so you will need to keep an eye on this.
Although manufacturers have come up with formulations that reduce the sheathing’s tendency to swell, this is still an issue. The edges of OSB can swell up to 15% when they are exposed to water, and these swollen edges do not hold fasteners as well as they should. This problem is especially acute when OSB is being used as a subfloor or underlayment for a ceramic tile floor.
Regardless of the manufacturer’s claims about waterproofing or no-sand guarantees, building consultants usually advise that builders store OSB under a roof and away from direct sunlight so it is not exposed to rain, snow, construction heaters, or the fumes of paint and other chemicals. It is also a good idea to provide ventilation in areas where sheathing is stored and used, as it will allow moisture vapour to escape.