Wood structural panels, more commonly referred to as plywood, are one of the most widely used materials in residential construction due to their strength and versatility.
While they’re ideal for constructing many wooden objects, they’re also an excellent material for use as roof sheathing because of their resistance to water damage and fire retardancy.
When choosing a wood structural panel for your roof, several factors will help ensure you adequately support your roof with the sheathing and thus remain structurally sound.
In this article, we’ll look at 3/8-inch plywood for roof sheathing.
3/8-inch plywood has equivalent strength to other structural roof sheathing choices. A 3/8-inch plywood roof sheathing panel comprises three 1/32-inch-thick veneer plies bonded with waterproof adhesive. To guarantee the plywood’s desired strength and longevity, all plies must be from high-quality structural grade face veneers with at least 90% wood fiber and no more than 10% synthetic fiber.
Ready for a Roofing Quiz?
Can You Use 3/8 Plywood Roof Sheathing?
The majority of roofs require plywood with a minimum thickness of 3/8 inch. Therefore, roof sheathing thickness is an essential building code item when deciding which type of wood panel roof sheathing to use.
In addition, most codes require a minimum amount of flooring material on a roof to prevent stress cracks, buckling, and other problems.
If you’re building a wood-framed roof, there are five types of panel roof sheathing that you can use.
These include plywood, OSB (oriented strand board), wood boards, and wood structural panels and planks.
For a good reason, plywood is the most common type of panel roof sheathing used in residential construction.
3/8 plywood roof sheathing is the material of choice for roofs with rafters spaced 16 inches apart and a light load on the roof.
The roof’s angle affects the load; the more horizontal the top, the more weight spreads across the top. Therefore, roofs with a steeper pitch will support less weight per square foot.
A roof with rafter spacing of 16 inches and minimum roof loads, which vary according to the roof’s pitch, requires just plywood with a thickness of 3/8 of an inch.
Generally, the load distributed over any roof area increases when the top is flatter.
The steeper the roof, the less weight is supported by each square foot of the top. Most residential roofs use standard 3/8 plywood as sheathing.
However, consider using a thicker wood structural panel if you plan to tile your roof or live in an area where strong winds are common (where wind-borne debris can potentially cause damage).
For roofs in regions where there isn’t much snowfall or where they design buildings to maximize airflow, 3/8-inch panel roof sheathing will suffice.
Although 3/8-inch panel roof sheathing won’t hold up well in snowy or windy regions, it can be an excellent solution for lighter-weight applications like wall panels and sheds.
As long as you don’t need your structure to support heavy loads, 3/8 plywood will work fine.
When it comes to your roof sheathing, plywood roof sheathing is one of your most cost-effective options.
It’s also one of your more versatile choices: you can install it in various ways and orientations, using nails or adhesives.
If you plan to use 3/8 plywood as your roof sheathing, be sure it’s rated for spans per local building codes.
Is 3/8 Plywood Ok For the Roof?
Yes, 3/8 plywood is ok for your roof.
For example, a roof with 16-inch rafter spacing and minimal roof loads uses 3/8-inch plywood, but when working with ceilings with more than 16-inch rafter spacing, say a 20-inch or a 24-inch-apart rafter, you can use it, but I recommend you use 1/2 or 5/8-inch plywood.
3/8-inch plywood is a common choice for roof sheathing because it is about as thick as possible without getting into dimensional lumber.
However, there are some clear downsides to using 3/8-inch plywood for roof sheathing.
The first thing that comes to mind is that unless your manufacturer offers different grades of plywood (there are usually 3), 3/8′′ might not be strong enough and could result in a saggy roof.
After all, your roof supports thousands of pounds!
It will probably be ok if you go with 3/8-inch plywood and have a roof that spans at least 14 feet.
However, if you plan to span a top of fewer than 14 feet with 3/8-inch plywood, I won’t use it as your primary sheathing material.
3/8 Plywood Roof Sheathing Span Rating
A 3/8 plywood roof sheathing is rated to span 16 inches with a minimal load and can be used to span 20 inches, and you can even see it in some panel roof sheathing of 24 inches, but before using it, ensure that it’s rated for spans per local building codes.
A 3/8 plywood roof sheathing is rated to span 24 feet by using a chord spacing of 12 feet. You can use this wood roof sheathing thickness in various residential construction projects and commercial buildings.
Three hundred fifty pounds per square foot is the maximum load supported by roof sheathing made of 3/8-inch plywood.
When choosing plywood to use in your home, it is essential to know how much weight you will be putting on it. For example, suppose you are going for strength and durability over longevity.
In that case, you can use thicker wood sheathing thicknesses such as 1/2 inch or 5/8 inch, but remember that they will be heavier and more expensive.
3/8 plywood roof sheathing price
At Menards, 3/8 plywood roof sheathing costs $35.13, with an 11% mail-in rebate G available for $3.86; the final price is $31.27. At Lowe’s, the price goes for $31.98.
Prices for 3/8 plywood roof sheathing can vary depending on size, quality, brand, type, thickness, and the store where you purchase it.
You can buy 3/8-inch plywood roof sheathing from large home improvement stores or contractors.
You may also get it free from a store that sells new or used building materials, although you will likely have to pay a fee to dispose of any other materials you remove from your home.
Regardless of where you purchase 3/8 plywood roof sheathing, consider whether it meets all applicable local building codes and how easy it is to work with before making your final decision.
3/8 Plywood Roof Sheathing Ideas
There are many choices for contractors and homeowners choosing which type of plywood sheathing to buy for their upcoming project. One of these is the 3/8 inch exterior grade panel roof sheathing.
An excellent place to start would be talking with your contractor about their past experiences with 3/8 inch plywood and asking why they chose that sheathing over others.
After all, they have probably been in your shoes before! In some states, 3/8-inch plywood isn’t widely used, and using it becomes a violation because it has a shelf life and is thin, so it doesn’t last as long as other plywoods.
In some cases, suppose your house has 3/8 plywood roof sheathing; you must replace it with other plywood due to their local codes and thinness.
When installing 3/8-panel roof sheathing, pre-drill any nail holes over 1 1⁄2 from an edge. It will prevent the splitting and cracking of your lumber during installation. Can I Use Cedar Breather or Lath on My Walls?
Conclusion
You use the 3/8 plywood roof sheathing for commercial and residential buildings, but there are some cases where it isn’t allowed.
However, according to some codes, the 3/8 plywood roof sheathing is used in houses spaced 16 inches apart, 20 inches apart, and 24 inches apart.
Therefore, a roof with 16-inch rafter spacing and minimum roof loads, which vary by roof pitch, requires 3/8-inch plywood.
