Homeowners want their homes to be tight, dry, and energy efficient year round. To that end, and also to keep up with ever-changing energy codes, home builders apply a sheathing around exterior walls and roofs to keep moisture out and prevent air leakage. This results in code-compliant homes, homeowners saving money on energy costs, and families living in a comfortable ambient temperature inside their home, no matter what the temperature outside is.
Home builders and remodelers have choices in the type or types of structural sheathing they apply. Among these choices are ZIP System® Sheathing, traditional sheathing panels such as plywood panels and oriented strand board (OSB, an engineered lumber similar to particle board), radiant barrier sheathing for roofs, and other specialized sheathing types.
What Is ZIP System Sheathing?
ZIP System Sheathing, manufactured by Huber, is a wall and roof barrier system for providing energy efficiency, moisture resistance, and a reduction in air leakage. ZIP panels are engineered to allow for drainage if excess water gets in (for example, as a result of a hurricane or flooding) and also to promote the escape of water vapor, which means faster drying.
This system is comprised of panels made of engineered wood and eliminates the need for traditional house wrapping. The company also provides a specialty tape, described as “high performance acrylic adhesive” that provides a permanent seal when panels are joined.
One benefit to using ZIP System Sheathing is how quickly and easily the product is installed, as it eliminates the need for separate wrapping. Also, the weather barrier is integrated onto the panels and cannot be damaged or blown off by high winds or pounding rain. Lastly, the manufacturer offers a 30-year system warranty.
OSB and Plywood Sheathing Panels
OSB sheathing panels are manufactured by combining strands of wood with waterproof adhesive to create a layer. Some 50 layers are hot-pressed together to make a single panel. The layers are perpendicular to each other. OSB panels can be made in different sizes, which means home builders can buy the size that is right for the project. When compared to plywood panels, OSB is stronger overall and also less expensive.
Plywood panels, on the other hand, are made from layers of wood veneer – called plies – that are essentially crisscrossed and laminated together with a hot press. Plywood has a smoother appearance than OSB, thanks to the continuous sheets of veneer used in the manufacturing process.
Both plywood and OSB panels can be used for walls, sub-flooring, and wall and roof sheathing, and industry experts say they can be used interchangeably. OSB and plywood are comparable in weight and strength. The difference between these two materials lies in how well they perform when exposed to moisture for an extended period of time, something that happens regularly during construction projects in climates where rain, snow, and ice are regular seasonal occurrences.
Plywood expands when it is exposed to moisture, but it also dries out more quickly than OSB and returns to its original size and dimensions. In contrast, OSB swells along the edges when it gets wet and the edges remain in a swollen position once it finally dries out.
When plywood or OSB panels are used for sheathing, wrapping is applied as an added layer of protection from the elements – a step that is not necessary when ZIP sheathing is used. Each type of sheathing has its pros and cons. When you understand the differences among all the products, you can make the most informed choice possible.
Steve Rush, owner of Sovereign Construction Services, brings knowledge and experience to every home construction and remodeling project his company completes. As a full-service home renovating and contracting company, he considers all construction options and decides what is best for the homeowner based on budget and need. Steve is available to answer your questions regarding sheathing. Call him today at 610-639-2986.