Should there be gaps in roof sheathing?

The recommended maximum gap between roof sheathing boards for low-quality, 3-tab shingles is 1/4-inch. If asphalt shingles are installed over sheathing with gaps exceeding 1/4-inch, over time, these gaps may telegraph through and become visible.

Should roof sheathing be spaced?

The panels should be spaced 1/8-inch apart at the ends and edges. The panel ends must be joined over a support. The panel joints should rest along the center line of the support framing with at least 1/2-inch of bearing. Tongue-and-groove edges or solid blocking may provide support at the edges.

What is spaced sheathing on a roof?

Spaced Sheathing, also called Skipped Decking, refers to the construction details of the substrate which the cedar gets nailed to and thus secured to your home.

Should you leave a gap between plywood?

APA recommends a 1/8-inch space between panel edge and end joints. Plywood and oriented strand board (OSB), like all wood products, will expand or shrink slightly with changes in moisture content. If the wood structural panels are tightly butted, there is no room for expansion and buckling can occur.

Does plywood need an expansion gap?

Unlike laminate floors which float over an existing floor and have expansion gaps, plywood is usually screwed or nailed into position and expansion gaps are not necessary. You should fit the plywood sheets tight together , but always leave a 10mm expansion gap at the perimeter.

Gapping OSB (or Plywood) sheathing

Can you install shingles over spaced sheathing?

The recommended maximum gap between roof sheathing boards for low-quality, 3-tab shingles is 1/4-inch. If asphalt shingles are installed over sheathing with gaps exceeding 1/4-inch, over time, these gaps may telegraph through and become visible.

How do I know if my roof sheathing is bad?

If the roofline is in any way wavy, then it means your sheathing is damaged and needs to be replaced. You can also check for sagging from the inside. Go into your attic with a flashlight, and look up. If any areas of the roof appear closer to you than others, your roof is sagging, and it is time to call a professional.

What does skip sheathing mean?

Skip-sheeting, or spaced sheathing, is just as it sounds: sheathing with gaps between. Traditionally, skip-sheathing consists of 1 inch by 4 inch boards nailed to the rafters with gaps between the boards. Spacing between boards is optimal for wood shakes but cannot support asphalt composite shingles.

Does OSB board expand?

Yes, in order to avoid dilation stress on the board edges. Expansion gaps are narrow distances that must be provided at the panel joints when fixing the straight-edge OSB boards on supports.

How do you fill gaps in roof sheets?

Foam fillers should be used to fill the gaps at the ridge and eaves ends of sheets. Eaves fillers fitted underneath the sheets whilst ridge fillers are fitted on top of the sheets and underneath the flashing*. Foam fillers are supplied in pairs with a ridge and eaves profile for each sheet.

What is the gap between roof rafters?

Standard industry roof rafter spacing is 12”, 16”, 19.2”, and 24” on-center, however other spacing may be used by a Structural Engineer. Depending on all contributing factors though, 16” and 24” are commonly used for most buildings. The wider the space between rafters often results in rafters of greater depth too.

Is it better to nail or screw roof sheathing?

Nails are often preferred for structural joining, including framing walls, because they are more flexible under pressure, whereas screws can snap. Nails are also called upon when securing plywood sheathing for exterior walls, installing hardwood floors, and attaching siding and roofing.

Can you roof sheath with OSB?

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.

Do all roofs leak a little?

Nearly All Roofs Leak -- A Little / Commonsense suggestions can minimize problem. The root purpose of every dwelling is to provide shelter from the elements, and an architect's most fundamental charge is to design a weather-tight building.

How do I know if my plywood is bad on my roof?

Wet wood rot tends to look discolored or darker than the roof around it. Dry wood rot tends to look like a fungal growth, and it makes the wood cracked and dry. Here are some more signs to help you identify wood rot in your roof: Wood is darker in spots.

When should roof plywood be replaced?

How long does roof plywood last? Roof plywood should last twenty years, so long as it is not exposed to water.

Is 7/16 OSB OK for roofing?

OSB is the most-used sheathing material for new roofs and roof replacements. You can use 7/16-inch thick OSB sheets without support for areas where the snow load is 30 pounds per square foot because it's durable and maintains building integrity much longer than other sizes.

What is the minimum thickness for roof sheathing?

The minimum requirement for roof sheathing is ⅜” thick. There is no upper limit on how thick your roof substrate is. Thickness allowed depends on how far apart rafters or trusses are spaced and the rating of your roof decking.

Is roof sheathing considered structural?

Roof sheathing is structural, providing lateral bracing of roof framing members, and it carries both live and dead loads from above to the rafters and trusses below. Similar to exterior wall wood sheathing, roof sheathing includes plywood, oriented strand board and waferboard.

Does OSB sheathing have to have 1/8-inch gap?

The APS recommends keeping a 1/8″ gap between OSB or plywood sheets when used on roofs, floors, or walls. That makes a lot of sense since both types of sheathing absolutely will expand and contract. But I don't get how that works out of a span.

Should underlayment have gaps?

To avoid buckling, subfloor panels should be spaced with a 1/8-inch gap at all edges and ends to provide room for naturally occurring expansion.

Does wet plywood expand?

What Happens if Plywood Is Stored in Wet Conditions? Generally, if common plywood gets wet for an extended period of time, it can swell and lose shape which eventually leads to the layers of wood splitting apart. This often occurs when plywood is stored outside for even a short timeframe before a project begins.