sheathing
Sheathing is one of the simplest materials used in the construction of a building. It refers to the panel used to construct the first layer of a wall or ceiling. Once the joists have been added, or the framework of the wall is in place, sheathing is attached using nails. Other parts of the wall or floor are then attached to this sheathing to allow the remainder of the building to take shape.
Within the world of sheathing, there are a number of brands producing very similar products. Products such as ZIP Sheathing, LP, and Georgia-Pacific are all commonly seen names on the side of construction projects. If you are building a home, then your best course of action is to use an experienced contractor to attach the sheathing. They will also be able to recommend different brands and types.
This guide will give you an overview of the different options of sheathing on the market. That way, you will be best-placed to know what types of sheathing you should be asking for. If you are doing the job yourself, it’s always best to consult with a professional if in doubt, as generally, the different types of sheathing are for specific functions, meaning if you buy the wrong type, it won’t be fit for purpose.
So, use the guide below as a key part of your research and make sure you’re using the best materials in your building project.
WHAT IS SHEATHING?
Sheathing is the material used to form the basic framework of a building as part of the floor, wall, or roof assembly. As mentioned above, once the basic skeleton structure of the home is complete, the next step is to add the sheathing to the joists and frames to provide a more solid structure and to provide a base on which to attach the other features of the wall, floor, or roof. This is the most basic use of sheathing.
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Floor Sheathing
In addition to the basic framework function, sheathing actually carries some structural value. This is particularly true of floor sheathing, which must be able to carry loads from above onto the floor joists. The floor sheathing is usually the first sheathing to be installed, as it allows contractors to move throughout the different floors of the building (and therefore install the sheathing on the walls and roof).
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Wall Sheathing
Wall sheathing’s primary function is to help with protection against wind and water from entering the building. In some cases, it may also have a structural component (these options will be discussed in more detail below).
A key metric to use when considering wall sheathing is the R-value, which refers to the level of insulation that the sheathing offers; the higher the number, the more insulation. Wall sheathing has the largest range of options and products on the market and, depending on your specific needs, you’ll be able to find a specific sheathing brand and model for you.
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Roof Sheathing
Like floor sheathing, roof sheathing also carries some structural value. It has to provide lateral bracing to the roof joists, thereby improving the overall structural soundness of the nascent building.
COST OF SHEATHING
The average cost to install sheathing is between $3 and $7 per square foot, so that comes out to around $1,500 – $3,500 for a 500 square foot area. This figure includes materials and labor. Although this number can change depending on the difficulty of the project, your location, and the materials used. For example, plywood sheathing will cost you more than oriented strand board sheathing (OSB). More information on the different options of sheathing available in the next section.
Option 1: WOOD-BASED STRUCTURAL SHEATHING
When discussing the different types of wood-based structural sheathing available, the usual materials include plywood, OSB, and waferboard.
PLYWOOD
Plywood sheathing is made from sheets of wood that have been cross-laminated, giving a great deal of strength and structure. Not only does it provide solidity, however, but also flexibility – making it suitable for dealing with expansion and contraction due to temperature and moisture levels. One problem with plywood is that it can be susceptible to having weak spots in its construction, which leaves core voids in the sheathing panels.
A key benefit of plywood is that it is between 15% and 20% lighter than OSB. It also is fairly resistant to moisture and dries quickly when it does get wet. This makes it an ideal choice to provide exterior sheathing to a construction project.
ORIENTED STRAND BOARD
OSB is a type of sheathing made of hundreds of thin wooden strands that are pressed together to make sheets with a wax and resin adhesive. This makes it extremely durable because of how dense and solid it is. It also avoids many of the problems of plywood, since it cannot be made with soft spots or core voids. However, because of the way OSB is made, it does not dry very quickly, and it doesn’t breathe well at all (due to its density). The price of OSB varies greatly, although generally, it is cheaper than plywood.
WAFERBOARD SHEATHING
The cheapest option of all is waferboard sheathing. This is may by placing very small pieces of wood scraps into an industrial hydraulic press and then gluing the pieces together. As a result, you produce very cheap panels for use in sheathing.
While this is the most cost-effective type of sheathing, it is also the weakest, meaning it is best suited to dry conditions where it is required only to insulate. Alternatively, you can use this in situations where it is not exposed to the elements for a long amount of time.
Option 2: GYPSUM BASED STRUCTURAL SHEATHING
Unlike plywood-based options, gypsum is made by wrapping gypsum with a paper surface. Gypsum is an extremely cheap and robust option for sheathing, although it must be used in certain parts of the project and not others. Gypsum sheathing is known as drywall, wallboard, or plasterboard.
The big benefit of gypsum sheathing is that it is extremely fire-resistant and sound resistant, and therefore provides a good insulator. The big limiting factor when it comes to gypsum is the fact that it is damaged very easily when it gets wet. For this reason, it’s not suitable for use on external walls.
Similarly, it can’t be used for rooms that will experience high levels of humidity, such as bathrooms or laundry rooms. This obviously limits its use and ensures that the optimal way to use it is in combination with plywood sheathing.
Gypsum sheathing is, therefore, best used when the waterproof envelope of the building is in place. It is also a good option when you are undertaking renovations in a home or building that is already waterproof. It’s also a good option in this situation as it allows for you to sound and heatproof the room as quickly as possible.
Alternative Options
The most common types of sheathing are those listed above – plywood or gypsum. However, there are other options available that fit specific niches. Some of these include the following:
GLASS MAT SHEATHING
Glass mat sheathing is similar to gypsum board, although the key difference is that the outer coating is a fiberglass barrier, rather than a paper material. This type of sheathing is most commonly used in large commercial buildings.
CEMENT BOARD STRUCTURE SHEATHING
This is made by taking Portland cement and reinforcing it with a glass-fiber mesh around it. This makes it easy to attach to a wall. The advantages of this type of sheathing are that it is non-combustible and it provides an extremely strong, solid base if you are planning on attaching tile or other types of masonry products. Because of the weight of these, traditional sheathing may not be able to stand up to the job.
THERMO-BRACE SHEATHING
This is a type of structural sheathing that is made from very high-quality, long fibers. These fibers are specially treated to be water and weather resistant. This also makes them extremely strong structurally. The key advantages of this type of sheathing are the ability to support the integrity of the wall system, as well as creating a tight and weatherproof building envelope.
In some cases, this type of sheathing can also be made airtight, although this is not the default. This is, therefore, a good option to use in conjunction with gypsum boards as interior sheathing.
There are other types of sheathing available, although these tend to fill very specific niches. If you are undertaking a project that may need this kind of niche, speak to a professional who will be able to advise on the best type of sheathing to buy. In the vast majority of cases, however, the sheathing listed above will be more than enough.
Getting the right sheathing for your purposes can actually be an important process.
It’s not one of the first things you consider when building a home or office, although it is a vital step in ensuring your building remains strong and protected as you build.
If in doubt,
you should always consult with a professional as to the best type of sheathing for you. However, there is a wide range of companies on the market, all producing high-quality levels of sheathing, which means you will be able to find a good quality option for you.
Do your research and you’ll be prepared to invest in the best sheathing for your construction project.