What Kind Of Plywood For The Roof
When it comes to choosing what kind of plywood you need for the roof, it is important to understand the basic categories that you can choose from. Most construction sites will consider the use of either OSB or plywood for the roof.
CDX plywood is a construction-grade type of plywood that is designed for exposure to the elements. It can withstand moisture for a brief period of time but may become warped and delaminated with consistent exposure to the elements. This particular type of plywood is crafted from layers of wood stacked on top of one another with alternating grain patterns in each layer. The alternating grain gives the plywood a system of checks and balances that allow it to expand and contract evenly across the sheet.
Here is another option for plywood you might think about: RTD Plywood: Everything You Need to Know
Alternatively, OSB is created from wood chips, resin, and adhesive that is baked and formed into the shape of a sheet of plywood. It is extremely resistant to moisture. However, when it is penetrated by water, it takes a very long time to finally dry out compared to CDX plywood. The edges may also swell during this time, creating small yet visible ridges on the roof where the boards meet.
What Thickness Plywood Is Used For Roofing
Now, it is time to figure out the plywood thickness for roofing. Basically, there is no setting stone for this. However, these thicknesses are just the most common ones. They do become the standard when people use plywood as the materials for their roofing selection.
The minimum flat roof plywood thickness is around 3/8 inches. This is like the necessary thickness to have when you want the plywood to hold the structure of the roof sturdily. The most common thickness of plywood sold in stores is around this thick as well.
Most buildings, especially the commercial ones, are using ¾ inch plywood roofing. Plywood of this thickness allows the roof to contain debris, snow, and dirt quite strongly, and they wont affect the roof or making the roof fall that easily.
It all starts by choosing the right plywood thickness for roofing.
Now, you have read almost everything related to the thickness. When you have decided to go with plywood for the roof, you can consider choosing the best material and the standard thickness so that the roof will be installed on the top of the house for decades without having to be replaced too often.
How Much Does Mdo Weigh
MDO: Medium Density Overlay is a type of exterior plywood specifically designed to be painted easily, holding the paint better, and looking better after painting, than other types of engineered wood panels.
The wood plies are typically softwood, and a thick, smooth layer of a highly water-resistant resin is applied to one or both sides of the panel.
A typical 4 x 8 sheet of 1/2-inch MDO weighs around 48 lbs.
Also Check: What Is The Most Durable Type Of Roof
How Much Does Marine Plywood Weigh
: Despite its name, this is not a waterproof plywood. It is manufactured using water-resistant adhesive and very high quality outer plies which help prevent moisture from penetrating the panel.
It is designed to be used where the material will be subjected to higher-than-normal amounts of moisture, such as in coastal environments.
A typical 4 x 8 sheet of 1/2-inch Marine Plywood weighs around 51 lbs.
How Much Does Softwood Plywood Weigh
Softwood Plywood: This is the type of plywood most commonly used in construction.
Structural plywood is usually softwood plywood. It is used for roof sheathing, wall sheathing, subfloors, and more.
Softwood plywood comes from coniferous trees, primarily fir, pine, or spruce. It is generally the lightest type of wood panel, due to the light weight of the wood species used, the low amount of adhesive used in the manufacturing process, and the presence of unfilled voids within the inner plies.
It is normally the cheapest plywood. CDX plywood is a grade of softwood plywood.
A typical 4 x 8 sheet of 1/2-inch Softwood Plywood weighs around 43 lbs.
You May Like: How Long Does A New Roof Usually Last
What Kind Of Plywood Should You Use For A Shed Floor
Before we decide which plywood is the best for a shed floor, lets take a look at what options there are. The term plywood originally meant layers of wood veneer glued together. Today, it refers to all types of engineered panels made from wood products.
- Softwood plywood is the most common. It is made from 3 or more layers of pine, spruce, or fir veneer glued together. The grain in each layer is perpendicular to the previous layer. This makes it stronger than an equivalent thickness of the wood. The sheets are cut into 4 X 8 panels. Hardwood or cabinet grade plywood is made the same way as softwood plywood, but the two exterior faces are hardwood.
- is specifically designed for boats. There are no gaps in its construction and water boiled proof glue is used to keep it together. Its 3 times more expensive than softwood plywood.
- Particle Board is made of sawdust and glue. Is very brittle and doesnt survive moisture. MDF is made of wood fiber and glue. It is slightly stronger than particle board but as susceptible to moisture.
- OSB is made of wood chips or strands glued together. About 50 layers make it stronger than the 5 to 7 layers in softwood plywood. Its used for subfloors, roof decks, and wall sheathing where it can be protected from moisture by other layers.
- Baltic or Russian birch and ApplePly are made from multiple layers of thinner veneer. Often used for furniture or design work, it is much stronger than regular plywood. However, it is much more expensive.
Plywood Used For Roofing
Exterior Plywood is the preferred material for roofing. It also performs well when exposed to moisture over long periods of time. The price is low compared to other roofing materials and the installations are also easy.
Some types of plywood are used for roofing, Construction structural, and general plywood, and CDX plywood.
Structural plywood is of two types A and B-Bond. A is more durable and stronger than B-bond. But B-Bond Structural plywood is also used for use of exterior applications
- C the grade of the front of the plywood sheet.
- D the grade of the back of the plywood sheet.
- X the type of glue used to bond the wood layer.
You May Like: How To Install Insulation Under Metal Roofing
Below Are Some Comparisons
1. The Oriented Strand Board is considered more structurally consistent than plywood as it compacts more strands of wood in a sheet of the same thickness as that of plywood.
2. While OSB absorbs less moisture, plywood absorbs more but dries out more completely and faster.
3. The Oriented Strand Board does not delaminate, affecting plywood, but it is mainly prone to swelling at the edges when exposed to water.
4. Oriented Strand Board is cheaper than plywood.
Many Factors Affect Thickness
The thickness of plywood used for roof decking depends on the roof slope, the spacing of rafters and the weight of other material to be put over the decking, as well as the design “load” the amount of pressure exerted by various forces and the weather, especially weight of snow or ice accumulations. The wider the rafter spacing, the heavier the shingling, the lower the slope and the heavier the weather load, the thicker the plywood will have to be.
Recommended Reading: What Is A Roof Certification Form
The Thickness Of Plywood For Roofing
When it comes to selecting an appropriate thickness of plywood for roofing, a few factors come into play. The choice will mainly depend on:
- The space between rafters.
- The slope of the roof.
- The weight of any other material that you plan on installing on top of the deck.
- The load of the design is the stress that the roof is expected to endure due to weather elements and various forces, especially the weight of ice or snow build-up.
As a rule of thumb, the wider the space between rafters, the heavier the shingling. This lowers the roof slope, which causes the weather load to be heavier. Consequently, the thicker the plywood youll need to use.
What Size Plywood Should You Use For Your Roof
The industry offers a thickness of anywhere from 5/16 inch to ¾ inch. So, what size plywood should you use for your roof?
There are several factors to consider:
- How the roof is designed.
- The spacing of the rafter.
- The expected load.
A half inch thickness is considered to be standard in a lot of areas and it should work just fine considering that its deemed okay by the roofing contractor after considering the things above. Its the standard for spacing of 24 inches in the rafter, although as mentioned, a 5/8 inch thick is more ideal. You might be tempted to choose a ¾ inch thickness although its unnecessary in most cases.
You can get plywood sheets with a length of up to 10 feet. The standard width is 4 feet.
Talk to a professional so that the factors will be properly considered so you can make the right choice on the best wood.
What Size Roof Sheathing Should I Use
Roof sheathingshouldSheathing shouldroof sheathingshouldsheathing
What size plywood should be used for roofing?
Most Common Thickness For rafters spaced 20 or more inches apart, 1/2- or 5/8-inch plywood is recommended. The most common rafter spacing is 24 inches, and 5/8-inch plywood is recommended for that. It will support roof loads for most situations and is the standard for most roof applications.
what is better for roofing OSB or plywood?plywoodplywoodOSBplywoodroofplywood
Roofing Plywood: Sizes Material Options Thickness Calculations Osb
While its not the main material for the roof itself, roofing plywood is an important part in a roofing structure. Its so important that you have to arm yourself with knowledge and know everything there is to know so youll know the best way to utilize it for your roof.
Read on to know more about this material. Youll know how its used for decking and sheating. Youll also know the different size and thickness requirements. Youll also learn how to calculate to find out how many sheets you need for your roof.
You May Like: Can You Put A Skylight On A Flat Roof
Is Osb Or Plywood Better For Shed Floor
OSB and plywood are both commonly sold in 4-by-8-foot sheets, but OSB can be made in much larger panels, up to 8-by-24 feet. Using larger OSB panels can be an advantage when flooring a big or odd-size shed, reducing the number of joints in a floor. Plywood shed flooring is usually 3/4 inch and OSB 5/8 inch thick.
Recommended Thickness Of Shed Roof Sheathing
The recommended thickness for roof decking on a shed is . At that thickness, you can economically sheath your shed while still getting an extremely solid roof substrate that will stand the test of time.
OSB board is preferable to plywood for sheathing a shed. Strand board that is tongue and groove makes for a very straightforward install on your shed. If your rafters or shed trusses are widely spaced, or uneven then the tongue and groove give the edges additional strength, particularly if they arent supported by framing at every edge.
The strand board, besides being cheaper, also works extremely well with tar paper. The rough surface of OSB as compared to the smoother surface of plywood allows the tar paper to hold better and makes installation much faster.
And while plywood may dry faster than strand board, its important to note that all strand board roof decking you buy these days has blue edges. That means the edges have been waterproofed, which makes it much less likely water will penetrate the board. The adhesives that bond the strand board are also waterproof.
You could always opt for thicker roof deck panels, but for a shed there is no need to go thicker if your framing is of standard width. Once you start buying panels that are greater than thick, youll notice the cost rise significantly.
Recommended Reading: What’s The Average Cost Of A New Roof
What Thickness Should Roof Sheathing Be
The typical thickness of roof sheathing is about 7/16-inch, which is just under 1/2-inch.
What is the best sheathing for a roof?
The two most popular roof sheathing materials are OSB and plywood. Both of these are more economical than radiant barrier roof sheathing and zip system roof sheathing. Because of their affordability, most homeowners opt for one or the other. However, there is some debate as to which material is the best.
Plywood Thickness For The Roof
One of the most important factors when selecting the plywood for your roof is how thick each piece should be. Like most other things, there is no one right answer for the plywood thickness of your roof. The answer depends mostly on how far apart the rafters are and the roof loads, which vary based on the pitch of your roof.
The most common scenario is a home that has rafters set approximately 16 inches apart. In this case, plywood should be a minimum of 3/8 inch thick. However, you may need to consider bolstering the plywood thickness for a roof that has a higher load. A roof that lays practically flat will have a much heavier load than a steeper roof that allows rain, snow, and ice to roll right off.
Rafters that are slightly farther apart might require ½ inch or 5/8-inch-thick plywood. Many homes have rafters that are even wider at 24 inches apart and will require a thicker sheet of plywood. When this is the case, experts recommend a 5/8-inch-thick sheet. Keep in mind that the load of the roof still plays a role in the plywood thickness. A flatter roof with rafters farther apart may need a thickness of up to ¾ inch.
Read Also: Can I Pressure Wash My Roof
Mastering Roof Inspections: Asphalt Composition Shingles Part 38
The purpose of the series Mastering Roof Inspections is to teach home inspectors, as well as insurance and roofing professionals, how to recognize proper and improper conditions while inspecting steep-slope, residential roofs. This series covers roof framing, roofing materials, the attic, and the conditions that affect the roofing materials and components, including wind and hail.SUBSTRATES
Substrate is a generic term that refers to an underlying supporting material. In addition to roofs, a substrate can refer to walls, floors, and even soil. When discussing roofs, the substrate can be the wood roof sheathing or, if new shingles are being applied over old, the old shingles could be considered part of the substrate.
Sheathing is a more specific term used to describe boards or panels that form the roof deck. Since sheathing also describes rough wall and floor coverings, well use the full terms roof sheathing and roof deck.
In older homes, the roof sheathing is usually wood boards. Over the years, plywood replaced boards, and oriented strand board, or OSB, has gradually replaced plywood.
Typically, older homes were originally roofed with wood shakes or shingles.
To encourage drying, they were laid over wood-board roof sheathing, with spaces left between the boards to improve air flow. When the original wood shakes or shingles failed, they were typically replaced with asphalt shingles, which require solid sheathing.
Plywood and OSB
What Is Roof Decking/sheating
Also known as sheating, decking is basically where the roofer attaches the shingles or whatever your chosen roofing material is. Obviously, it should be graded for exterior use meaning it should be able to withstand rain especially during the construction of the roof. The waterproofed coat of plywood makes it a top choice along with OSB, planks and wood boards.
What is plywood? Plywood is made out of laminated sheets of veneer. Its a top choice because of its characteristic wherein it expands evenly when exposed to water unlike OSB wherein only the edges expand.
Speaking of OSB, its a top choice of homeowners looking for something more affordable than plywood. As a warning, its considered by some to be inferior in quality as compared to plywood. Well discuss plywood vs OSB more later.
Recommended Reading: How Much Does A Roof Cost In California
Why Is Plywood Used In Roofing
Roofs are built from rafters and trusses, which make up the framework of the roof, but a flat deck then needs to be laid on top of the frame, which the final roof material can be fixed to, for example, tiles or felt. Plywood is an ideal material for the deck of a roof because it is inexpensive and durable. Using solid wood would be a waste in this instance because the deck of the roof wont be seen once the roof is complete, so it doesnt matter what it looks like. Plywood offers the strength required to hold the load of the material which will go on top of it, along with heavy snowfall or ice.
Plywood has a good level of water resistance, which is useful when used in outdoor applications such as roofing. In the event that it does expand due to moisture, it does so evenly so that the structure of the roof is not affected. It also dries out quickly, which reduces the chance of mold buildup and other moisture-related issues.
Plywood is also easy to work with and can be cut to size using handheld saws or circular saws. The standard size for sheets of plywood is four feet by eight feet, which makes it a reasonable size to work with while also covering a decent surface area on the roof. Larger sizes are available, though less common. Plywood is also available in various thicknesses to suit different loads.