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OSB is now the most-used sheathing and subflooring material for new roofs and roof replacements. OSB is currently selling for less than plywood by approximately $3 per sheet, meaning a savings of several hundred dollars per conventional home.
What is the best thickness for roof sheathing?
The recommended thickness for roof sheathing is ⅝” thick. Sheathing with a thickness of less than that is much more likely to result in bowing between framing which could potentially compromise your exterior roof material.
What is the most common roof sheathing?
OSB (oriented strand board) is the most common type of decking used on roofs today. It’s made up of wood chips/strips compressed together to form a flat 7/16” sheet. Plywood comes in several different thicknesses (⅜”, ½”, ⅝”, and ¾”) depending on the span of the rafters.
Which is better plywood or OSB?
Osb is stronger than plywood in shear. Shear values, through its thickness, are about 2 times greater than plywood. This is one of the reasons osb is used for webs of wooden I-joists.
What are the different types of roof sheathing?
Roof sheathing is usually made of either oriented strand board (OSB) or plywood. Both materials are made of wood, but OSB is more lightweight and costs slightly less. Plywood is very durable but tends to cost a bit more and is heavier.
Can 3/8 OSB be used for roofing?
Standard types of wood designed for roof sheathing are oriented strand board, known as OSB, and plywood, the most popular being OSB. With edge support and the same snow load, 3/8-inch OSB can be used.
Is CDX plywood good for roofing?
Moisture Differences In reality, CDX plywood can only withstand water for a short period of time. Do not use CDX for roofing, sheds, or other places that are exposed to moisture consistently. The sole exception to this is pressure treated CDX, which can survive for decades without even a protective coating.
What is CDX plywood used for?
CDX Plywood is used primarily by contractors to build exterior walls and roofs. CDX plywood has one side veneer grade “C” and one side veneer grade “D”. The two are bonded together with glue which can withstand a little moisture. The APA would recognize CDX Grade Plywood as C-D Exposure 1 plywood.
What type of plywood is used for roof sheathing?
CDX Plywood A special grade of plywood called “CDX” is a popular choice for roof sheathing. No, the “X” in CDXplywood does not stand for “exterior.” Rather, it references the kind of glue used to bond the layers of veneer together. CDX plywood can withstand temporary exposure to rain and other moisture sources.
Should you use tongue and groove OSB for roof sheathing?
Tongue & Groove Boards T&G roof decking, however, looks classy and rich. In fact, T&G boards are most frequently used when the sheathing is visible from the inside such as in cathedral ceilings or in some cabin-style homes, especially if the span of the rafters is greater than 2 feet.
Do screws hold better in OSB or plywood?
Group 1 plywood, made from the strongest species of wood such as Southern Yellow Pine, holds screws better than OSB.
Which is cheaper plywood or OSB?
OSB is less expensive than plywood. To build a typical 2,400-square foot home, OSB may cost $700 less than plywood. OSB is considered by many to be a “green” building material because it can be made from smaller-diameter trees, such as poplars, that are often farmed.
Is OSB more water resistant than plywood?
OSB is more resistant to moisture absorption but also takes longer to dry out. Plywood absorbs moisture faster but also dries out much faster, but extended moisture exposure can cause plywood to delaminate.
How far should roof sheathing overhang fascia?
Ideally the sheathing should be on top of the fascia without extending beyond it. Guesswork can create a situation in which it extends too far and it interferes with flashing installation, or you have to cut it. If the fascia is to be one layer of 1x, I overhang the sheathing 5/8.
What is open roof sheathing?
Open sheathing, also called skip sheathing, is composed of boards spaced apart. This type of roof sheathing is used under wood shingles and shakes, which usually require ventilation on both sides of the roofing material.
How thick should plywood be for a shed roof?
Plywood thicknesses for roofs start at 3/8” in areas with light load requirements on rafters at 16” centers. Thicknesses of 1/2 to 5/8 inch are common with rafters spaced at 24” centers. For heavy load rated areas, 3/4-inch-thick plywood is recommended, regardless of rafter spacing.
Do you need plywood under shingles?
Sometimes referred to as roof sheathing or a roof deck, this plywood acts as a foundation for the layers of underlay and the shingles on your roof and connects the roof to the frame of the house. Even though it isn’t visible, it is very important to the structure of your home.
What is the nailing schedule for roof sheathing?
As such, the nailing schedule is typically the familiar 6 inches on center at supported panel edges, including gable-end walls and 12 inches on center over intermediate panel sup- ports. Note, however, that minimum 8d nails (0.131 x 2-1/2 inches) are recom- mended for all panels 5/8 inch thick or less.
