Wooden roofs are a popular choice among homeowners due to their eye-catching appearance and numerous benefits. There are two main types of wood for roofing: handsplit and resawn and tapersawn. Handsplit and resawn shakes have a rustic appearance, while tapersawn wood shakes have a semi-textured look with a stronger shadowline. There are two styles of wooden roofs: wood shake or wood shingles, with wood shakes being cut into perfect shapes. Asphalt shingles, made of asphalt reinforced by fiberglass or other materials, are also popular.
There are four shingle grades: 1 the best grade, taken from the tree’s heartwood, 100 edgegrain with no defects, used for roofing and sidewalls; 2 flatgrain with limited sapwood allowed, limited knots and defects. The best type of plywood for roofing is exterior CDX plywood, made from a combination of hardwood and softwood veneers that are bonded.
There are two basic categories of residential roof decking: sheet decking and plank decking, and a third type, metal decking, sometimes used in more industrial settings. Exterior plywood is durable, stable, and water-resistant, mainly used for outdoor purposes. It is weather and moisture-resistant and typically made from spruce, Douglas fir, birch, and other hardwoods.
There are two types of plywood used in roofing construction: structural and general plywood. Structural plywood has proof of strength performance provided by its strength. There are over 20 different types of plywood, including softwood, hardwood, aircraft, exterior, and lumber core plywood.
Ceramic, teak, and redwood are among the best woods for outdoor use due to their natural resistance to moisture, insects, and decay. Both OSB and plywood are made from very different components, with OSB being the most dense and plywood being the most wet-performing.
📹 Which is better, OSB or Plywood?
Roger compares OSB 3 board and plywood and gives his opinion on the best option. OSB board vs Plywood (from Champion …
Is CDX exterior grade?
The letter “X” in CDX plywood refers to the type of glue used to bond the plywood veneers, not the exterior. The letter “X” stands for exposure, meaning the plywood is tough enough to withstand moisture but only for a short time. It is primarily used by contractors for building exterior walls and roofs. CDX plywood has one side veneer grade “C” and one side veneer grade “D” and is bonded together with a moisture-resistant glue. It is important to note that “outdoor”, “exterior”, and “pressure treated” should not be confused. Pressure-treated plywood can survive outside for decades without paint or a protective finish.
How thick should wood be for roofing?
The thickness of roof sheathing varies from 5/8″ to ½” (15. 9 mm to 12. 7 mm), with OSB installation requiring a thickness of 5/8″. Plywood should be ½” thick. The recommended thickness is ⅝”, and the minimum sheathing requirement is ⅜” thick. The recommended thickness for OSB and plywood is 5/8″.
Which is stronger, OSB or CDX?
OSB is suitable for medium humidity environments and is less strong than CDX but can withstand moisture exposure for a short time. It is commonly used for walls, floors, and roof sheathing. OSB is not fully waterproof and cannot withstand constant water or moisture exposure. Its gapless structure and resin content allow it to withstand moisture longer. CDX, on the other hand, has low moisture resistance but is treated for better durability and improved termite and rot resistance.
Is AC plywood exterior grade?
In the context of exterior or weather-sensitive projects, the optimal choice of plywood is ACX or marine-grade plywood, which are the most suitable for such applications.
What grade timber for roofing?
C24 timber is commonly used in load-bearing structures like roof trusses and floor joists, while C16 timber is used for non-structural purposes like internal joinery and general construction. C24 timber allows for smaller and fewer knots, which can affect its strength and load-bearing capacity. Additionally, C24 timber is straighter and has fewer deviations or twists, which is crucial for structural applications as it affects the stability and performance of the timber components. Both types can have knots, which can affect the strength and load-bearing capacity of the timber.
What type of plywood for roof?
CDX plywood is the highest grade of plywood, free from knots and imperfections. It is suitable for use under shingles and roofing felt, and on the underside of the plywood sheet. It represents an ideal balance between price and functionality. Half- or three-fourths-inch plywood is traditionally used for roof sheathing, but heavier loads may require three-fourths-inch plywood. OSB (oriented strand board) takes longer to get saturated when wet and to dry, and its edges may swell when exposed to moisture.
OSB manufacturers address this with a special edge sealant, but on-site cuts remain vulnerable. ZIP wood, an engineered product, is known for its strength and durability, with a water-resistant barrier that breathes and eliminates the need for roofing felt. All five layers of ZIP system insulated sheathing are moisture-resistant, making it suitable for areas like Montgomery County with variable weather conditions.
Can all wood be used outside?
Before starting an outdoor project, consider the wood type, its exposure to elements, its natural resistance to rot and insects, and the best treatment method. Most woods are resistant to rotting, while moderately resistant woods include Douglas fir, larch, sapele, and meranti. Hardwoods require more upkeep due to weathering and fading, which can cause discoloration, surface cracks, and warping. A UV-blocking finish or topcoat can protect them from fading. Opting for a hardwood that is resistant to deterioration, such as thick or oily wood, can lower the chances of fungus infection.
Outdoor finishes for hardwoods should be UV-protective and waterproof. For outdoor projects like building a deck, trees from the Far East, like Balau, can be used without treatment. These woods have exceptional resistance to decay and can last for many years if not kept too wet and away from the ground.
In summary, selecting the right wood type for an outdoor project requires careful consideration of exposure, resistance to rot and insects, and future upkeep.
Is exterior grade plywood the same as marine grade plywood?
Marine plywood is made using permanent weather and boil proof glue, while general exterior plywood uses other types of WBP glue. Marine plywood standards prevent defects, even on the surface, ensuring water-resistant properties. However, exterior plywood can allow for some defects, typically found on C-D grade plywood. The thickness of marine plywood ranges from 1. 3mm – 3. 8mm for multi-ply construction and 0. 5mm for three-ply construction, while exterior plywood can come in thinner veneers for affordability.
What wood will last longest outdoors?
Wooden outdoor furniture is generally considered the most durable and rot-resistant type, with hardwoods like ipe and teak being the most durable. These woods can last decades with minimal maintenance, making them ideal for outdoor use. However, it is important to note that any wood outdoors will eventually degrade over time, so it is recommended to use natural oil finishes that can be replenished. Plastic clear coats can eventually yellow and start peeling off, making them unrepairable.
To maintain wooden outdoor furniture, it is essential to clean it with soapy water at the start of spring and apply a couple of coats of your chosen wood stain or paint. Some people let their furniture age naturally, giving it a rich golden brown color, but personally, I prefer a rich golden brown color. Applying an all-weather varnish, such as BEHR Premium Transparent Weatherproofing All-In-One Wood Finish, with a repeat application in Spring every 2-3 years, can help seal up the wood from outdoor elements like UV light, rain, snow, wind, and hail.
Choosing the right wood species reduces the need for regular care, but it does not mean regular care won’t extend the life of furnishings or improve their appearance. All furnishings should be given an occasional cleaning to get rid of dirt and grime, using a dilute solution of Murphy’s oil soap and water. Silicone-based cleaners and polishes are the culprits, so avoid them. Do not soak or flood the furniture while cleaning.
The most severe damage occurs from direct sunlight, melting snow and ice, or standing water. To extend the usefulness of furnishings, they should be protected from direct rain, snow, and sunshine. UV rays break down all woods eventually, and excessive moisture is necessary for fungi, mold, and insects that break down wood. It is best to keep a moisture barrier between wood furniture and the ground, as water will wick up from the soil.
It is best to bring wood furniture indoors for the winter, as melting snow can keep it damp for weeks on end. The freeze/thaw cycle can also damage joints and loosen screws. Do not drape the wood with plastic, as dew can form underneath and cannot evaporate quickly enough for the wood to dry.
Lastly, a water-proof topcoat, such as Le Tonkinois, can extend the life of any furnishings. Jacob Aune’s personal favorite is Le Tonkinois, which is easy to apply, water-proof, and holds up better than most spar varnishes available at home improvement centers.
What are the different grades of exterior plywood?
Plywood is a crucial material in construction and woodworking, used for various purposes such as roof sheathing, subflooring, room dividers, and cabinet and furniture projects. Grade A is the top-tier grade, with a smooth, sanded surface free of knots. Grade B is slightly lower quality, while Grade C has noticeable defects and knots up to 1-1/2-inches. Grade D is the lowest grade, with knots and defects up to 2-1/2-inches. The lumber industry grades plywood through four main levels: A, B, C, and D. Custom cabinetry requires higher grades than roof sheathing.
What is the best wood for outside roof?
Teak, a Brazilian hardwood, is known for its high oil content and durability, making it an ideal choice for outdoor projects. Its density and natural oils contribute to its longevity, while its distinctive grain and strength make it a good choice for weather resistance. Oak, a Brazilian hardwood, is known for its strength and distinctive grain, making it a good choice for weather resistance. When choosing timber for outdoor use, consider factors such as durability, resistance to weather and pests, maintenance requirements, and aesthetic appeal.
These factors influence the performance of the timber, ensuring its longevity, aesthetic appeal, and environmental sustainability. Choosing the right timber for outdoor projects can significantly impact the success of your project.
📹 OSB vs. Plywood: Which Should You Choose for Your Roof Deck?
What do you need to know when deciding between OSB and plywood for your roof deck? Comment below to have your question …
Curious as to your thoughts on the mixing of OSB and plywood on an existing roof deck. In performing some assessments, we come across situations where damaged plywood panels were replaced by OSB. My preference as an engineer would be for uniformity across an area. Wood engineering and construction is already a science of variability. Adding variability is a nightmare, even if testing. While one would hope that any adverse impact may be slight, it probably is a function of the ratio of area replacement as well as the location. In design, added unpredictability results in an increase in the factor-of-safety. Always a challenge facing unconventional construction techniques, particularly those of the DIYers.
What happens when you install underlayment and shingles on top of a soaking wet roof decking? The roofers patched 2 areas maybe 4×4 decking with OSB and the outer soffit area – the part you see with APA 32/16 exposure 1 – Thickness 0.451, 15/32 Category. I read that off the plywood. And is it even more compromised with a ton of bad empty knot holes and just crappy, splintery wood? I watched the wood as the roofers walked onI it. Glad they didn’t fall through. I am trying to learn as much as I can about wood, the weather and roofing. Thanks
Having a home built. Being a construction idiot I’m trying to inhale everything I can about materials. Between OSB vs Plywood, insulated studs, high grade siding, house wrapping and more, I’ve come to the conclusion that you probably can double the purchase price of any home depending on materials used. Next week I meet with the main man for the first time, on the 2 acre parcel we have. He’ll be my contact throughout the building process. Already having signed a purchase agreement, he can surely talk circles around any concerns I might have while being considerate and professional, so I fear my concerns won’t change a thing. It all comes down to where I want the money to be spent, inside and outside I guess.
Why not use treated plywood? It is rot and termite proof. The roofing might fail but the deck won’t. Fasteners do need to be hot-dipped galvanized or stainless steel and care must be taken about metals in contact, but this is all manageable. Standard CDX is only capable of withstanding short-duration weather exposure, and OSB not at all.
I know that OSB is relentlessly pushed in the USA. I prefer for all outer surfaces plywood, that is roof and outer cover of the outside walls.. Plywood is more impact resistance than OSB. On the inside I prefer OSB, it does not carry sound like plywood. My roof would have on top of the beams 12 or 15 mm plywood, than 2 x 2 stringers following the beams, covered by 1 x 6, than tar paper than galvanised corrugated steel, round, the thickest available, screwed down.
In my experience, plywood ages much better… and if it gets a little wet (not completely soaked for a long time), it can survive for reuse with much less swelling. Get OSB damp, and it’s trash. I’d say if you have an application where you want it to be repairable and have more durability, go for plywood. Double the cost? Still worth it.
Diagonal laid strapping on top of the sheathing, with Coravent on three sides, provides under-metal ventilation to the ridge. The strapping holds the metal roof fasteners better than either plywood or OSB, and it vents moisture out, to keep things dry under the metal. Cover the sheathing with a self stick smart vapor membrane, and the sheathing will dry through it.
Our GC has talked repeatedly how our house has been over-engineered. We have 3 steel I-beams, zip system on walls, Advantech sub floors with gorilla glue and just found out he installed 1/2″ OSB on our roof! We have a standing seam metal roof being installed. Also, the Tarco NR600 membrane is wavy and lifting up on two peaks. What do you think we should do? This roof is very expensive and was purchased for longevity. I’m afraid we won’t get the longevity with what is currently happening and given the decking thinness.
I have a shingled roof right now with 7/16 OSB. When it’s time to replace, I was thinking of going with metal, but it sounds like to pullout values are too low, so it wouldn’t be a good idea. What if diagonal furring strips were layed down first, and screwed right into the joists? Would those strips then have adequate holding strength and make this feasible? If so, how significantly would this add to the cost?
Yes, I agree with plywood I would make that extra investment and use pressure treated plywood. Now for the tight wadds out there that wants to pocket the money by taken short cuts again the cheap comes out expensive at the end the price difference between regular plywood and pressure treated plywood is worth the investment long run..when constructing.a structure you can’t have a mind frame well if I buy the lowest quality materials I can pocket more money your mindset should be what materials high quality that will last long term for the comment I received claiming that I’m waisting money have said that if I built my home too last by using high quality long lasting materials would you want me too build your.house using my mindset of a shortcut mindset. Best Regards,
Neither osb or ply are great choices, best results are to be found using traditional sarking, that’s rough sawn timber boards, (treated,) this is the traditional form of roofing finish to take slate in Scotland, note not in England, this is more reliable than particle board, which is prone to deterioration if subjected to moisture. OSB will blow & lose its structural integrity & ply will tend to delaminate. The sarking will also take nailing for fixing to the roof frame with a much higher resistance to pulling out as the cellulose fibres in the timber have a tension that the particle boards don’t have. In exposed areas or locations that experience high winds this offers a far more robust roof frame, the sarking also gives the roof frame greater lateral strength than sheathing that combined with good detailing, such as ties to mitigate against lift, etc will give you the best results & if the workmanship is of a decent standard will last for a very long time, more than a lifetime. I’m based in Scotland but heading over to the States in the very near future. Texas to be precise. We are very experienced builders particularly using traditional building techniques, including natural stone walls built using traditional lime mortars. Our company is Cameron Building Services, based in Scotland you can Google us if you are interested