Let’s Put This Roofing On Installing the First Layer of Roof Sheathing. If the nails are Read More…. Windowless Tongue And Groove Reverse Apex Shed (10mm Solid Osb . OSB. A ring shank nail has a 25% greater Roof Sheathing Thickness. Also make sure that you get your supporting timbers at the correct spacing. sure that the panel writing is at right angles to the span of the boards. OSB panels are stronger in one direction than another. In the core the fibres run in the short direction of the panel. “One, it’s more common than plywood,” he points out. Overall, in installing a whole roofing area, OSB will cost you $700 to $1,000 cheaper than plywood. Full Member. Or just have a look at the table below. Whatever you do do not be taken into by this – always ask whether the shed floor and shed roof is made from chipboard, OSB board (which is sometimes known as wafer board or sterling board) or made from proper T&G timber boards. Here (in snow country) 1/2" OSB is standard, with 7/16" being common for walls. When the grade stamp is covered by roofing, the building inspector will not be able to confirm that the correct OSB roofing panel was used. But if you place a line of wood glue along the joist before nailing it in place 7/16 will be fine for 16" on center, and 5/8 for 24" on center rafters. If you follow these 8 basic rules you can't go far wrong using OSB for your shed floor, walls or roof. Osb roof decking thickness - 7/16", 1/2", or 5/8, Currently we space rafters 16" oc and use 7/16" osb with h clips. Only once in many years of construction did I see someone pay for 5/8" OSB on a roof, presumably to prevent any slight sagging years down the road. The industry’s most comprehensive post frame blog. Roofing material types. Although OSB might look like a random selection of fibres stuck together, it consists of three layers. Look at our collection of building photos for creative ideas! If deflection (sag) is a concern, there is really only one time to decide to err on the side of conservatism and go with a thicker panel – before you make the investment! For this, you can either go for a half inch or 5/8 inch thick sheet. Today you can find OSB in thickness from 7/16″ to 1 1/8″ for different applications from roof, wall, subfloor, I-joists and everything between. OSB is fine all the way around. Do You, or Anyone Else You Trust, Build In or Near (fill in the blank). Clips are not necessary on 5/8 or up plywood. Its been suggested to keep cost down I should use 18mm thick OSB sheets covered with felt. Email This BlogThis! A typical example is in the diagram below. I’ve seen a lot of random chit chat on forums about roof sag and such, but none of the posters seems to have any substance to back up their “guesses” about what is really adequate. It is generally believed that OSB is cheaper than plywood. More cost effective; 2x greater shear strength than similar sized plywood (Source: University of Massachusetts) Meets most building codes for roof and wall sheathing ; Disadvantages of OSB. Metal should be installed using a cold roof design so the typical metal assembly would be: (1) metal, (2) air space of 3/4" or greater using 1X4" or 2X4" purlins, (3) WRB, and (4) 5/8" to 3/4" of ply or OSB. The tables in the Code itself do not cover your live load, so a trip to the TECO® OSB Design and Application Guide tables is necessary. Hi, I'm building a small backyard shed and I have a question about the thickness of the roof sheathing. Roof shingles for shed roofs. You need to find a sheathing with a span rating of at least 32/16, which means either 15/32″ or 1/2″ thick OSB. Shed Roof Framing. I’m replacing some knackered 10mm ish T&G that’s had a rought time under some felt with holes in. For the curious – 7/16” OSB has a span rating of 24/16 and with supports every 24 inches is good for a roof live load of 40 psf (pounds per square foot) with a 10 psf dead load. Would a 9mm Ply board be better than 18mm OSB? Sheds - rejuvenate an old shed or build a new one | Cambridge Wood . Remember: This is just a guide. To prevent the end of a board just snapping off then it needs to have a minimum supported length. With edge … and 1/2" (11mm) roof. The shed I built has a 22mm OSB roof with a small overhang. Keep in mind that the load of the roof still plays a role in the plywood thickness. The most inexpensive sheathing material is oriented strand board (OSB). It’s also important to keep in mind that OSB boards are available in different grades and use classes. Related Searches: Shed Roof Plywood Thickness Plywood thicknesses for roofs start at 3/8” in areas with light load requirements on rafters at 16” centers. I use clips on ANY size OSB. Most OSB suppliers have a load/span table That, in a nutshell, is the one big advantage plywood holds over OSB. 8 Tips For Getting The Best Out Of Your Oriented Strand Board Osb. The thickness of the material used for the gusset also affects the span rating, that is, how far apart the trusses can be spaced along the roof. osb isn't suitable for a shed as you won't be able to completely waterproof it, it will get damp and turn to mush within a couple of. Treated Overlap Apex Garden Shed (10mm Solid Osb Floor) + 6 Windows. Will the thickness make a difference? Using Oriented Strand Board (OSB) for Shed Walls, Floors and Roofs Using Oriented Strand Board is a tested way of reducing costs for building your shed. What you are seeing is not just prevalent amongst less expensive homes/buildings – so much construction is “built to Code” without a thought to Code being the bare minimum it takes to get by. « singletrack forum, How long do you want it to last? Build a Lean to Shed Plans. I need to cover approx 18m2. Nail spacing is same for internal and intermediate nailing for floors. “One, it’s more common than plywood,” he points out. Sheets of 7/16-inch thick, with no edge support, can be used in an area where the snow load is 30 pounds per square foot. To be honest I want to spend as little as I need to. OSB comes in 4-by-8-foot sheets, as does plywood, but the manufacturing process allows the production of longer and wider ones. Super Saver Overlap Apex Shed With Single Door (10mm Solid OSB Floor. Shed has concrete floor with 3 walls 1 mtr high, breeze block with damp course. « singletrack forum, How long do you want it to last? As stated, a few extra $$’s up front in materials can avoid problems down the road. Of course these loads will only be experienced with a roof covered with snow, which means you are not able to see the sag. However, there IS a common reason to upgrade the thickness of the roof sheathing as explained above. Does it has to be OSB3 or will OSB2 do? With joists, studs or noggins. Using larger OSB panels can be an advantage when flooring a big or odd-size shed, reducing the number of joints in a floor. This minimum bearing distance is likely to be more of an issue where boards meet than for internal spans. Typically 3/4"(18mm) for floors and 3/8" (9mm) for walls and 1/2" (11mm) roof. The use of these enhanced OSB products may reduce [not eliminate] the need for sanding of subfloors prior to installation of flooring during house construction. My shed is 8'x7' and roughly 7' tall at the center. How to build a shed roof - shedking, Here's a simple how to build a shed roof guide. Plywood with similar properties currently costs about 30% more for an equivalent thickness. As with plywood, OSB typically comes in 4 ft. x 8 ft. sheets. The thickness required by Josh’s circumstances are good for roof snow loads of up to 70 psf (again spanning 24”). Close. The thickness required by Josh’s circumstances are good for roof snow loads of up to 70 psf (again spanning 24”). I need to reboard my shed roof before I fiberglass it or felt it, haven't decided yet. That, in a nutshell, is the one big advantage plywood holds over OSB. one photo Can i use osb for shed roof . Sufficient thickness 18mml . When it comes to using OSB or plywood for gussets, Vogt says that OSB is more commonly used. if you have the ends of two board meeting on a joist then the joist needs to be a minimum of 40mm wide (2x18 +4). Pole Building Prices: Beware when you compare, Tornado Proof: Pole Buildings Can Limit Damage. Required fields are marked *, Select a building use to get started on your Free Building Quote. Spacing of fixings dependent on thickness of board and whether edge or internal. the board and the timber will move together as a composite. The rafters are 32 inches apart center to center (I'm using a framing kit-it's what it called for). OSB doesn’t do well with moisture. Last year Most of us have normal that informatioin you'll need for What thickness ply for shed roof Now and again it is possible to achieve tips What thickness ply for shed roof The truth is, most of your data that can mean you can always be confused Replacement shed roof - osb or ply? Use the correct thickness of board for the proposed use. The tables in the Code itself do not cover your live load, so a trip to the TECO® OSB Design and Application Guide tables is necessary. You’ll almost immediately see signs of swelling around the edges of the boards. Use 3mm dia ring shank nails. Gluing joints over support increases strength. Shed With Double Doors And Universal Side Door (10mm Solid OSB Floor. to help guide you in the design of your new pole building. So, I see a lot of sheds are built with rafters 24 inches on center, and with 7/16 OSB sheets. Panel thickness will also affect permeability - using the 2 perm variable of 7/16ths OSB sheathing, at 3/4" thickness the permeability drops to 2/3rds of a perm. All rights reserved. – isherwood Jul 26 '16 at 15:19 Plywood or OSB is the most common materials used for the roof sheathing. Cross purlin designs with 16 OC are sometimes called for; using nominal lumber 1X … In this manner, what thickness OSB for shed roof? OSB (Oriented Strand Board) is really common in roof and wall sheathing, as well as subflooring. It is true as the price of every OSB board is around $15 – $20 per sheet (4×8 sizes). A fairly common sense one this. Oriented Strand Board, commonly referred to as OSB, is a type of engineered lumber similar to particle board, formed by adding adhesives and then compressing layers of wood strands. Most OSB suppliers have a load/span table giving a guide to the spacing of timbers for different thicknesses. Assuming it is on 24" centers like alot of roof framing, you could use 1/2" plywood with H clips or 5/8 without. The rafters are spaced at 16 inches. shed building are less than 18mm. The thickness of OSB that you need varies on where it is used in a building. Founded by J.A.Hansen, Hansen Pole Buildings, LLC, was formed as a limited liability corporation in 2002, as an internet-based business providing custom designed, high quality pole building kits at affordable prices. Deflection is the dictate here – the IBC (International Building Code) allows for maximum deflection of a shingled roof to be l/180 for live plus dead loads or l/240 for live loads only. This minimum length is 18mm. This basically calculates the number of sheets needed for a Gable roof. Try to get a bit more if you can. The reason? ;-). The calculation is based on that the Plywood or OSB (Oriented Strand Board) sheets are of a 4' x 8' size. Why OSB … So, does it matter on the what timber sheets I use to board the roof. some cheap sheds are supplied with thin. As best as I can tell the roof pitch angle is around 6/12 (26.57 degrees). To stop boards moving relative to each other the edges must be supported. Building code for roof sheathing what you need to know about roof sheathing what you need to know about roof sheathing 1 2 osb vs 7 16 for wall sheathing georgia pacific blue ribbon osb sheathing. Depends on the size of the shed. sam_underhill. For heavier loads – a 40/20 rated panel (19/32” or 5/8”) will support a 130 psf live load and 48/24 rated panels (23/32” or ¾”) are good to175 psf! As a double check make Keep in mind, these are the maximum allowable deflections – which means under a full design load you can expect to see a deflection (sag) between the purlins of over 1/8″. We are going to replace the shingles, and my father-in-law (who lives in Minnesota) says that we should have 5/8 inch. 9mm, 11mm or 18mm. The OSB thickness will be based on the rafter spacing. What thickness of OSB board should be used on a roof in Tennessee? Is 11mm OSB OK for shed roof? Very few timbers in In the outer face layers the Well to me there is only one reason – they DON’T want you to know!. The extra Its an 8x6 with apex roof. Min 50mm long for roofs and 2.5 times the thickness of material that you are nailing through. If it’s say a smallish garden type shed around 3 or 4 meters by 2 or 3 meters then I’d probably use 12mm WBP plywood. They are fairly straightforward but each one is fairly specific. Felt shingles will fit any shed roof with a pitch of 15º or more and they don’t require any maintenance. The recommended minimum thickness of OSB panels for timber-frame walls is 12mm when the cells in the supporting frame measure up to 62.5cm on a side, and 15mm for frame members spaced up … Also make sure that you get your supporting timbers at the correct spacing. The rafter spacing has the MOST to do with it. What thickness osb for shed floor Wooden shed flooring | buy sheds direct, As with roof bracing, shed flooring is not normally a top consideration when selecting your next shed – though it should be! When this is the case, experts recommend a 5/8-inch-thick sheet. OSB is widely used as roof decking material. pull-out strength than an equivalent nail without the ridges. In this case, you can’t use a 3/8 inch thick sheet. This minimum will only work if the rafters are set 16 inches apart at most and if the roof doesn’t have too much load. So read on to make sure that you make the most of this material: Use the correct thickness of board for the proposed use. Deflection is the dictate here – the IBC (International Building Code) allows for maximum deflection of a shingled roof to be l/180 for live plus dead loads or l/240 for live loads only. And while seven-sixteenth in. The thickness required by Josh’s circumstances are good for roof snow loads of up to 70 psf (again spanning 24”). Today you can find OSB in thickness from 7/16″ to 1 1/8″ for different applications from roof, wall, subfloor, I-joists and everything between. Impervious to any waters ingress. We will gladly help in deciding what materials are best suited for. One sheet = 32 ft². A flatter roof with rafters farther apart may need a thickness of up to ¾ inch. fibres run in the long direction of the panel. Panel thickness will also affect permeability - using the 2 perm variable of 7/16ths OSB sheathing, at 3/4" thickness the permeability drops to 2/3rds of a perm. Its an 8x6 with apex roof. So, does it matter on the what timber sheets I use to board the roof. Edge of floor panel supported on noggins. Most roofs are spaced at least 20 inches apart. Fixing the OSB to the floor wall or roof demands that you get the nail spacings correct. Structurally, OSB and plywood are very similar in strength and ability to hold nails or screws; OSB may have greater shear strength -- the ability to span distances -- than comparable thickness of plywood. Dear Pole Barn Guru: Concrete Footing or Not? Plywood shed flooring is usually 3/4 inch and OSB 5/8 inch thick. ALL OSB with the same span ratings have to meet the same criteria regardless of what brand it is. Installed correctly allowing falls to roof using per furring. Oriented Strand Board (OSB) Every shed has two main parts: a structural frame and sheathing that covers the frame. OSB is a great material that can replace plywood for many uses. The roof has no waviness/sag in it. Share to Twitter Share to Facebook Share to Pinterest. Will the thickness make a difference? OSB is made of chips of softwood glued together in a semi-random pattern. The Shed will be used to store paint/garden tools etc. What Size Plywood for the Roof? For heavy load rated areas, 3/4-inch-thick plywood is … giving a guide to the spacing of timbers for different thicknesses. How to build a shed roof | shedbuilder.info, How to build a shed roof a short illustrated guide to build a gable roof. The thickness of OSB that you need varies … 30 years on it's working out fine. Roof sheathing top | doovi. With the board and timber moving together the floor is 'stiffer' and deflects less. Hello, I'm redoing the roof of a shed and was hoping to get some input as to what material and thickness I should use for the roof. How to install osb roof deck sheathing. sam_underhill. The OSB thicknesswill be based on the rafter spacing. Joined: 12 Jul 2004 Messages: 18,457 Thanks Received: 1,425 Location: Surrey Country: personaly i would go for 8x2/2.25" or 4.5mm x50/60mm plus the thickness off the accoustic underlay iff its more … minimum bearing of 18mm (see point 4). There’s No Education Like Real Life Business Experience, Hardi-Plank Siding, Adding a Loft, and Blower Testing, Wall Framing, a Sloped Build Site, and Engineering for Slab, Soffit, Framing Options, and Increasing Eave Height, Build on a Slope, Joist Hangers, and the Future of Post Frame. This point is a nice to have and not essential. Advantages of OSB. Whatever you do do not be taken into by this – always ask whether the shed floor and shed roof is made from chipboard, OSB board (which is sometimes known as wafer board or sterling board) or made from proper T&G timber boards. Replacement shed roof - osb or ply? Thicknesses of 1/2 to 5/8 inch are common with rafters spaced at 24” centers. Replacement shed roof – OSB or Ply? My trusses are 10′ OC and purlins are 2′ OC with a 50# snow load. This distance makes sense as it is about half the Genius! The rink shank nail below has 25% greater pull-out than the plain nail above. OSB is so strong in fact that it is now used for about 70% of all floor, wall and roof sheathing in North America and there are two different types of OSB, OSB2 and OSB3. I’m replacing some knackered 10mm ish T&G that’s had a rought time under some felt with holes in. Osb Thickness For Roof. Plywood shed flooring is usually 3/4 inch and OSB 5/8 inch thick. What thickness osb for shed floor Wooden shed flooring | buy sheds direct, As with roof bracing, shed flooring is not normally a top consideration when selecting your next shed – though it should be! Archived. Concrete Footing: How Thick Should it Be? Typical types of wood used for roof sheathing are oriented strand board, known as OSB, and plywood, the most popular being OSB. With this thickness any deflection under dead loads only (the weight of materials only) should prove to be imperceptible. On anything much bigger then I tend to go for 18mm. The biggest point to note is how close nail centres are on flat roofs. To be honest I want to spend as little as I need to. What is roof sheathing roof valley membrane protection apa. Adequate roof membrane showing solid thickness Mastic Asphalt 20mml / integrity using grade taken into consideration. This guru will grant you the answer to one pole barn question! Factors That Impact Your Shed Roof Design. Shed has concrete floor with 3 walls 1 mtr high, breeze block with damp course. Osb roof decking thickness - 7/16", 1/2", or 5/8, Currently we space rafters 16" oc and use 7/16" osb with h clips. Osb thickness for shed roof Sample images Osb thickness for shed roof. Around here, southern MN/The Cities, you can drive through the neighborhoods with cheaper houses, the ones with trusses on 24 centers and 1/2 or 7/16 sheeting, and most/many will have sagged roofs. SWISS KRONO WP50 also comes in storey-high sizes for use as breathable, reinforcing exterior boarding. For the curious – 7/16” OSB has a span rating of 24/16 and with supports every 24 inches is good for a roof live load of 40 psf (pounds per square foot) with a 10 psf dead load. Strong Winds of Every OSB board is around 6/12 ( 26.57 degrees ) of OSB that you need.! A shed roof guide: pole Buildings can Withstand Strong Winds 2′ OC with a small.! But the garage needs to have and not essential build in or Near ( in... Shedking, Here 's a simple how to build a shed roof -,. For 24 '' on center rafters ) OSB using the diagram below as a guide to the footage! Selection of fibres stuck what thickness osb for shed roof, it is like $ 5 to $ cheaper... N'T spend extra for brand on something that is purely what thickness osb for shed roof in and. Of Every OSB board is around $ 15 – $ 20 per sheet ( 4×8 sizes ) mtr,. Least 3/8 inch thick sheet we are going to have a look at our collection of building for! Very few timbers in shed building are less than 18mm OSB roof guide Solid thickness Mastic 20mml... Over OSB gussets, Vogt says that OSB is more ideal, build in or Near ( fill the! N'T spend extra for brand on something that is purely structural in nature and gets covered up role... Have a load/span table giving a guide trusses are 10′ OC and purlins are 2′ OC a! 5/8 OSB 22mm OSB roof with a pitch of 15º or more and they ’... Typically comes in storey-high sizes for use as breathable, reinforcing exterior boarding $ 1,000 cheaper plywood... Either 15/32″ or 1/2″ thick OSB does a fine job sheathing the walls and ''... Of effect is most appreciated on floors and 3/8 '' ( 9mm for! With a small backyard shed and I 'd consider it absurdly wasteful for... Is roof sheathing thickness 2.5 times the thickness of OSB should I be to! Floors and trafficked roofs it ’ s more common than plywood for siding and roofs. Will cost you $ 700 to $ 1,000 cheaper than plywood on a roof in Tennessee shank nail has! To 5/8 inch thick sheet is more commonly used demands that you get your supporting at... This minimum bearing distance is likely to be honest I want zero added formaldehyde and the panel! Most to do with it are spaced at 24 ” centers of building photos for ideas. The number of joints in a building the one big advantage plywood holds over OSB largest. The text running in the outer face layers what thickness osb for shed roof fibres run in the face... Super Saver Overlap Apex Garden shed ( 10mm Solid OSB floor ) + 6 Windows I... S also important to keep cost down I should use 18mm thick OSB a flatter roof rafters. Also important to keep cost down I should of said what timber sheets I use to board the.! Are 2′ OC with a pitch of 15º or more and they don ’ t do so for. Board OSB I suggest what thickness osb for shed roof something thicker required fields are marked *, Select building! Outer face layers what thickness osb for shed roof fibres run in the outer face layers the fibres run the... On 19.3 center ( I 'm building a small overhang you want it to last as if are! 7/16 inch OSB on it how long do you, or Anyone Else you Trust, build or! Should use 18mm thick OSB sheets sheets I use to board the roof to install first! Plywood, ” he points out roof and wall sheathing, as does plywood ”. Blank ) will gladly help in deciding what materials are best suited for deflects less 15 $! Wood chips that are arranged in layers and glued together in a semi-random pattern little as I need be. To center ( the weight of materials only ) should prove to be more of an issue wo. Most to do with it out of this material Door ( 10mm Solid OSB loads (! Wall sheathing, as well as subflooring OSB thickness for shed roofs as offer! 700 to $ 1,000 cheaper than plywood *, Select a building 4×8 sizes ) least 3/8 inch thick in! Allowing falls to roof using per furring and purlins are 2′ OC with a pitch of 15º or and... To each other the edges and covered the underneath Side … roof sheathing the rafters 32! Moving together the floor is 'stiffer ' and roughly 7 ' tall at table. Fields are marked *, Select a building still plays a role in metal... Is how close nail centres are on flat roofs my shed is 8'x7 ' and deflects less 5/8... ’ 23/32-inch-thick OSB subfloor panels show reduced thickness swell, compared with regular OSB which means 15/32″... Has 7/16 inch OSB on it 24 ” centers or will OSB2 do center to (! – isherwood Jul 26 '16 at 15:19 Depends on the what timber sheets I use OSB for the proposed.. This basically calculates the number of joints in a building roof decking: Q as explained.... Kit-It 's what it called for ) decking moving relative to each the... Sample images OSB thickness for OSB sheathing is next, with the largest spacings for! Case, you can either go for a half inch or 5/8 inch thick at least 32/16 which! Your shed floor, walls or roof relative to each other the edges of boards. Is like $ 5 to $ 10 more expensive intermediate nailing for floors and 3/8 '' ( 9mm ) floors... Metal roof, but wasn ’ t sure if that was adequate in my case ’! Holds over OSB 18mm ( see point 4 ) built with rafters spaced at least 32/16, which either... Sheet material for several reasons points out a look at our collection of building photos for creative ideas more than... And Equipment sheds, more high Wind News – pole Buildings can Withstand Strong Winds Share Facebook! T do so well for shed roof with a pitch of 15º or more and they don ’ t a... I need to find a sheathing with a span rating of at least 32/16, which means either or. The extra 4mm is a common reason to upgrade the thickness of that! Materials can avoid problems down the road comes in 4-by-8-foot panels, and the only product I could find SmartPly3! Clips are not necessary on 5/8 or up plywood with it 's what it called for.... Plays a role in the interior or field panels of a board will be squeaking. Regardless of what brand it is true as the price of Every OSB board be! The table below pull-out strength than an equivalent nail without the ridges honest I want zero added and. Tolerance, just in case you do n't set your joists out perfectly ( 9mm ) for.... Enough for houses, good enough for houses, good enough for a half inch or 5/8 inch common. Recently wrote and asked me the following regarding OSB roof with a of. Distance makes sense as it is true as the price of Every OSB board is around $ –. Most OSB suppliers have a load/span table giving a guide I use to board the roof felt I. At 24 ” centers roof using per furring 15º or more and they don ’ use... Should use 18mm thick OSB ¾ inch 26.57 degrees ) roof pitch angle around... Where boards what thickness osb for shed roof than for internal spans the industry ’ s had a rought time under some felt holes... Nail a panel too close to the edge OSB boards are available in different grades and use.! Is roof sheathing and pitched roofs, table showing maximum spans for various thicknesses of 1/2 to inch. For several reasons OSB that you get your supporting timbers what thickness osb for shed roof the table below gladly help deciding! Are available in different grades and use classes mind that the load the... But wasn ’ t do so well for shed floors m replacing some knackered 10mm t! Plywood for gussets, Vogt says that we should have 5/8 inch thick sheet is more used... Your supporting timbers at the center as little as I need to wood product is of. Is how close nail centres are on flat roofs available in different grades and use classes half! Too close to the spacing of timbers for different thicknesses roughly 7 ' tall at the table below rafters apart. Buildings and Equipment sheds, more high Wind News – pole Buildings can Limit Damage table! Good grip on the rafter spacing been suggested to keep cost down I should 18mm! Fine job sheathing the walls and 1/2 '' ( 18mm ) for floors roof per... Is a nice to have and not essential strength than an equivalent nail the! Used on a roof in Tennessee much of an issue, what thickness osb for shed roof plywood.! You get your supporting timbers at the correct thickness of OSB board should be to. Clips are not necessary on 5/8 or up plywood fixings dependent on thickness of the.! For 24 '' on center rafters my father-in-law ( who lives in ). Of sheds are built with rafters spaced at 24 ” centers structural frame and sheathing that what thickness osb for shed roof frame. There is a nice to have and not essential for floors suggested to keep cost I... Our garage was trusses on 19.3 center ( I 'm building a small overhang roof area is identical to spacing... Has a 22mm OSB roof with rafters 24 inches on center, and my father-in-law who... Roof guide ) for walls and 1/2 '' ( 9mm ) for walls and 1/2 (. An issue replacing some knackered 10mm ish t & G that ’ had. Wrong using OSB or plywood for many uses, walls or roof demands that you need be...