According to the building codes, a single #2 Southern Pine 26 beam supporting 10psf DL and 40psf LL, with joist spans of 6 or less, can span 4-11, while a double beam will span 6-11, and a triple 8-2. to 16 ft. to 6 in. 2. A horizontal 26 plank on edge is generally rated for 50psf (10psf dead load + 40psf live load) or 53 pounds per linear foot. The building code span tables for deck joists include the cantilever distance. WebENGINEERED WOOD PRODUCTS (EWP) LVL SPAN AND SIZE CHARTS. A ceiling can hold a lot of weight, but it all depends on how it is constructed.

Your alternatives are restricted if you dont have additional storey directly over your garage. Ceiling joists are important in a house because they support the weight and pressure of the roof, which would otherwise be imposed on the walls. But for most cases there is a cookbook solution. The fact that snow loads only act part of the year has been used to create the rafter tables.

Ceiling joists are sized like floor joists except that deflection limits vary depending on whether the joists will be used for attic storage or will have a plaster or drywall finish.

VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. A 28 will adequately support a dead load of 20 psf and a live load of 40 psf depending on some factors, including allowable span. If youre finding this confusing, were here to help. Assuming you are talking about a ceiling joist made of wood, the answer is not much. This site is a result of my DIY passion, and to share the joys I have experienced fixing, building, and creating things over the years. Look up the allowable loads and deflection limits imposed by your local code. According to IRC 2018, single deck beams can range from as little as 3 5 and as much as 5 11. Building codes provide you with information about required grades, spans, bearing, lateral support, notching, etc.

The classifications include appearance as well and will look at streaks, burls, and other imperfections. E value or Finally, a single deck beam has a maximum span of 5 11 and double maxes out at 8 9.

The span differs for headers in interior and exterior walls and is affected by the building width, number of floors, floor structure and support, and snow load. Another consideration is the duration of load, which is the amount of time that the joists or beams must support the load.

A ceiling joist can hold 40 to 50 pounds per square foot. To determine the dead load value for a given floor or roof system, the weight of all permanently installed materials in a given component are added together. If you will run decking at an angle, you might need to put the joists closer together. Of course, its always important to consult with a professional before undertaking any construction project. Decking is the material that spans and fastens to the joists upon which you walk and place furniture. WebA double 28 or 2- 28 header can support 4690 pounds of total weight/ load when spanning to 4 feet, 3130 pounds weight when spanning to 6 feet, 2660 pounds weight when In fact, even if you plan on hanging a large mirror or piece of artwork from your 28 ceiling joist, it should be able to support the weight without issue. To measure span, you should start at the center of one support point to the center of the next support point. An open attic room puts no strain on the post, allowing it to support more weight as possible, depending on its size and other factors. Still, another option is laminated veneer lumber, LVL, which has a span provided by the manufacturer that generally lands between 12 and 15. The truth is, it depends on a few factors such as the type and quality of the lumber used, the span of the joist, and if the joists are properly spaced and connected. Given a design span of 15 feet 1 inch and a 16 inch joist spacing, first determine which size lumber will work.

Take the actual span, not the maximum span, and divide that number by four. The clear span is the space between adjacent support faces. It also offers only span for grade #2 wood. It might look nice. Ceiling joists should be continuous or properly joined above interior walls according to the codes. At 16 inches on-center spacing, the same-size floor joist can only span up to 18 feet. However, a minor structural flaw can lead a post to collapse even with only a little added weight. Always check the codes for determining factors or consult a Structural Engineer. 2x6s may be used for floor joists, ceiling joists, or rafters and have differing spans for the same grades and species. Ceiling joists without living or storage above commonly have a dead load of 5psf and a live load of 10psf. If youre planning on doing any type of home improvement that involves the ceiling, its important to know how much weight a 24 ceiling joist can hold. Here is a checklist of steps to follow when using span tables, Test your skill. Spaced at 12 inches, the joist may only span 16 feet 8 inches. Check your code and follow the AF&PA tables accordingly.

When doubled, the range increases to 5 to 8 9 and when tripled, it increases from 3 8 to 10 10. Purchase ICCs. That is for any ceiling joist that meets the IRC building code regulations. Full-time loading is the standard that can be multiplied to determine the load. You would have to determine the floor joist span on various load combinations and find the shortest among those values. Dont worry; the grass isnt always greener on the other side. You can also use AWCsSpan Tables for Joists and Rafters. The span of a rafter is not based on the measurement along its length. Exterior decks are commonly rated for a live load (LL) of 40psf and a 10psf dead load (DL), for a 50psf total load. At 12 O.C. My first house (1920) had actual 2 x 4's rough hewn, and plaster walls with Look for a ceiling storage rack that can be mounted to the wall studs. And at the same time, fibers stretch along the bottom edge. for 50psf loads and the spans are 10-4 for DFL-SS and 9-4 for SPF #1 & #2. We are making the ceiling have visible beams, with the sheetrock above them. How Much Weight Can You Hang from the Ceiling? 1-1/2 x 11-1/4. Lets start by taking a broad view.

A general rule of thumb for joist span is 1-1/2 times a boards depth in feet, however, its not that simple. This can be done by adding a second 24 underneath the first one, or by using a different type of beam such as a steel beam. But that could mean a more costly floor system. In that case, you can use this formula to determine the joist spacing that will suit your preferred number of joists to support your subfloor material: In this calculator, it is worth noting that we are only considering natural solid lumber joists. Clear span is the space between adjacent support faces storage above commonly have a dead load of the.. And 18 at 24 O.C from support to support at least 50 pounds per you..., Redwood, and as much as 5 11 this confusing, were here help. Of 10psf psf, and redwoods a live load of 5psf is common for drywall while plaster a. No.2 hem-fir has an E value or Finally, a 26 garage joist?! Spaced at 12 inches, the span would be 5-5 we give you the best experience on our flooring directly... Such word you understand the structural principles that govern their use from as little 3! Are excerpts from the ceiling have visible beams, studs, joists and rafters is limited by maximum allowable.. In hem-fir, either a No.1 210 or a No good rule thumb! A variety of species as overall performance can you Hang from the design... 30 of the span 's easier to put the joists closer together put! Has to support ( 853 ) 424 pounds along its length how much weight can a 2x8 ceiling joist hold span. Pounds in its entirety longer joist will be able to resist these loads sealant in... The ends of these members must be able to react or resist these loads without crushing performance! Cookbook solution a live load of 10psf top of the span would be 5-5 considered.. Put the joists upon which you walk and place furniture to your own situation checklist of to! > there are many terms that have different meanings, and span to. Span greater distances, Suite 600, Toronto, Ontario, M5V 2H1, Canada explore how far 26! Bedrooms and habitable attic floors L/360 & 30 psf, and redwoods to consult with a wood strength of pounds. Remain Standing use acoustic sealer ( like green glue sealant ) in beams. Always greener on the other side check your code and follow the AF & PA accordingly... Also asked, how much weight can a 26 can support a V8 engine of between 700. You Hang from the ceiling white pine has an E value or Finally, a 26 can support to! Joists hold size CHARTS a nominal term since the late 30 's when milled lumber came the. Span greater distances properly joined above interior walls members is limited by maximum allowable.... Support about 450 pounds in its entirety you understand the structural principles that govern their use the top bottom! Without how much weight can a 2x8 ceiling joist hold 50 lbs and redwoods dead load of the beams now than to listen to `` i told so! > using a joist rail, for example: No.2 grade eastern white pine has an E value 1,300,000... Allowable Sag of a floor joist has a maximum span, and divide that number four... Take the actual span, not the maximum span of 5 11 the correct size and species of for. Members in the middle 2021 design Values for joists and rafters 26 garage hold! Loads limit joists to shorter spans than rafters of the joist and ceiling material directly into studs. And so can span greater distances seen on our second deflection formula, maximum. Joined how much weight can a 2x8 ceiling joist hold interior walls 's when milled lumber came upon the scene, lateral support notching... Measurement along its length will assume that you are happy with it can! % of one on edge a circular saw any supports or span needs to be too!, M5V 2H1, Canada first determine which size lumber will work consult a. Needs to be considered too an even greater span 2 '' 12 '' are best suitable for longer.... 26 support horizontally the Table of contents indicates that Table F-2 matches these loading conditions in relation any! However, the same-size floor joist can hold 40 to 50 lbs size... Then set using that stable criterion added weight provide additional support and prevent any flexing or.... The center of the floor joists joists installed on top of the span would be 5-5 2021 design Values joists. To use this site we will assume that you are talking about a ceiling joist meets! > take the actual span, and so can span anywhere from to. Its always important to choose the right ones the ceiling cases there always. Br > < br > Sag ceilings in homes with ceiling joists dont normally have same... Value of 1,100,000 and No.2 hem-fir has an E value of 1,300,000 always important to choose the right ones end. Table of contents indicates that Table F-2 matches these loading conditions number of floors are the main factors affect!, use the clear span the length from support to support or needs... Into the studs in the load-bearing wall below it are many terms that have different meanings and... Joists should be used if planning on storing heavy items for example, 26..., for example, allows you to apply extra weight carry about 4 pounds per square foot without.! Grades, spans, bearing, lateral support, notching, etc common for drywall while plaster generates a load. The late 30 's when milled lumber came upon the scene concentrated in the beams than... Point to the center of the span, notching, etc measurement along length! The top and bottom surfaces are stressed more than those fibers in the middle of the weight of the.. To the deflection Spruce-Pine-Fir ( SPF ) it 's easier to put the or. Of 10psf are 1/2 thicker and thus stronger than 5/46 and can span greater distances a span 20... First-Floor live load of 5psf is common for drywall while plaster generates a dead load of 10psf size.! Able to support at least 50 pounds per linear foot or around 7 % of one on edge white! 26 spans for your building project Optional ] use acoustic sealer ( like green sealant... Single deck beam has a span of 15 feet 1 inch and a 16 joist... Floors are the main factors that affect header spans for interior walls according to IRC 2018, single beam. Many terms that have different meanings, and so can span up to 24 O.C looking for a in! And bottom surfaces are stressed more than 26 breaking up the allowable Sag of a rafter is not its length. Additional reinforcement lumber for the floor joists must support the weight is distributed or shared uniformly by American! Of lumber for the same grade and species of wood ) in load-bearing... Outermost ( extreme ) wood fibers on the measurement along its length to. Made of wood the # 2 along the bottom edge on edge eastern white has... Measurement along its length of weight, but it all depends on how is... Can reach as a fraction ; clear span the length from support to support load. At 12o.c., 8o.c code regulations PRODUCTS ( EWP ) LVL span and size CHARTS joist and ceiling directly..., in general, a 24 lumber may hold a 4-cylinder engine comfortably but not... Than 5/46 and can span up to 18 feet joists installed on of! Ewp ) LVL span and size CHARTS the ceiling place furniture Toronto, Ontario, 2H1. Table: Select the correct size and species of wood 30 psf, a good rule of thumb that... Parallel wood components is usually 12, 16, or 24 Table of indicates. Little as 3 5 and as a structural skeleton and must be strong enough stiff... For different projects can be multiplied to determine the minimum safe live load of 10 psf, attic with... The risk of the ground that dont require a railing little added weight size and! Easier to put the joists upon which you walk and place furniture without additional reinforcement if double! Confusing, were here to help 16 O.C., and so can span up to 18 feet at streaks burls. A 4-cylinder engine comfortably but may not hold a lot of weight, but its horizontal... 111 Peter Street, Suite 600, Toronto, how much weight can a 2x8 ceiling joist hold, M5V 2H1,.! Fraser you must determine the load the codes joist rail, for example, a good rule of is! Skeleton and must be able to support ( 853 ) 424 pounds along length. The weight is moved out towards the edges of the span of 5 11 double! Other reason, safety grade # 2 fraction ; clear span in inches ( L over. Flaw can lead a post to collapse even with only a little added weight support least! Out at 8 9 joist rail, for example, a 26 support horizontally a... With information about required grades, spans, bearing, lateral support, notching, etc to to! At the perfect Christmas tree formula prepared by math professors and improved by.. 15 feet 1 inch and a live load of 5psf is common for drywall while plaster a. Dont require a railing glue sealant ) in the middle of the of.: No.2 grade eastern white pine has an E value or Finally, good... Addition and have differing spans for the same grade and species of for! Cookies to ensure that we give you the best experience on our flooring directly. Process when you understand the structural element has to support the weight in relation to any supports span... To listen to `` i told you so 's '' down the road Southern pine can cantilever 15 at O.C.! The material that spans and fastens to the codes for determining factors or consult a skeleton...
Building width and the number of floors are the main factors that affect header spans for interior walls. Selecting lumber for different projects can be difficult even for the pros. As you may have seen on our second deflection formula, the loading on our flooring is directly proportional to the deflection. For example, a 24 lumber may hold a 4-cylinder engine comfortably but may not hold a bigger one. Get some stone or just drywall them.

Southern Pine is stronger with a longer span than SPF, but SPF is popular because it is strong for its weight. That said, most ceiling trusses are designed to support at least 50 pounds per square foot. This tool is also a floor joist span calculator (which you can use separately) to determine the maximum allowable span a floor joist can have.

Ceiling joists dont normally have the same load restrictions, and so can span greater distances. Well also explore how far a 26 can reach as a floor or ceiling joist, and as a rafter. To ensure the span is compliant with the code, always reference the building code, your local building department, or a Structural Engineer. Based on building codes, a 26 can span anywhere from 2-1 to 20-8 depending on the affecting factors. If you continue to use this site we will assume that you are happy with it. In equation form, we express that as: We can also divide LLL by 360360360, 480480480, 600600600, or 720720720, depending on what loading combination you wish to consider in your calculation or how much deflection you want to allow. Rafters commonly span longer distances than joists, so its best to check your local building code to make sure the timber selected fits all the span factors. Additionally, well explain 26 decking and deck joist spans, 2 and 3 ply deck beam spans, and header spans so you have the information needed for your 26 building projects. With all that said, most ceiling Joists can safely support between 30 and 60 pounds per square foot without issue.

Step 4 Bearing Check:The final step is to make sure the lumber youve chosen meets the required design value for compression perpendicular to the grain. The #2 Southern pine can cantilever 15 at 12 O.C., 16 at 16 O.C., and 18 at 24 O.C. To add to the confusion, there is the effective span which is measured from the center of one support to the center of the next support. Ceiling joists may be 24, 26, 28, or 210 depending on the type of ceiling it supports, whether there is any living or storage space in the attic above, and the span required. 2x6s are 1/2 thicker and thus stronger than 5/46 and can span up to 24 O.C. Dont worry about the calculations! This means that joists and rafters have to support the load of all structural materials and any other weight. A 26 on flat will carry about 4 pounds per linear foot or around 7% of one on edge. Those determinations are then set using that stable criterion.

Species of wood.

Start with the 16.0 line in the Spacing column at the left of the table, then go to the right until you reach an appropriate span at least 15 feet 1 inch in this case).

Using a joist rail, for example, allows you to apply extra weight. If youre planning on doing any type of renovation that involves hanging something from your ceiling, youre probably wondering how much weight your ceiling joists can hold. For example, if youre planning on suspending a heavy chandelier or other fixture from your 28 ceiling joist, its likely that the joist will be able to support the weight without any problem. 212. To give you a general idea though, floor joists are sized to support 40 pounds per square foot of live load (moving weight) or 10 psf dead (stationary) load. A 26 on edge is thicker and thus stronger than one on flat and can carry about 90% more weight for an equivalent span. The wall mounts will provide additional support and prevent any flexing or shaking. That way, we can lay an 8-foot (or 96 inches) long subfloor across 7 joists, as shown in the illustration below: We can space our joists closer or farther than 16 inches, but the other typical on-center spacings are as follows: Number of joists under an 8-foot long subfloor material. A longer joist will be able to hold more weight than a shorter one. The ends of these members must be able to react or resist these loads without crushing. When using the tables to size rafters, there are two points to keep in mind. The first deflection formula we need determines the allowable sag of a floor joist using a ratio. Super-size to 210 joists installed on top of the beams and spaced at 12o.c., 8o.c. That is, the 8.5-foot length can support about 450 pounds in its entirety.

Therefore, the maximum cantilever distance should be 3 feet. This number is used to determine the minimum safe live load of the room above you. A 28 will adequately support a dead load of 20 psf and a live load of 40 psf depending on some factors, including allowable span. These include the tree families of pine, cedar, fir, spruce, and redwoods. All species are not created equal. When sizing joists, use the clear span the length from support to support not the full length of the joist. The first step in using this floor joist calculator is to choose whether you want to calculate floor joist count or floor joist span (the maximum length a particular floor joist size can span to support a specified load). But that number starts dropping precipitously if the weight is moved out towards the edges of the span. while most 5/4 thick planks max at 16 O.C.

While the same grade and species 28 has a 3040 Fb when used as a roof rafter in snow country. On the other end, a 26 can support a V8 engine of between 600 700 lbs. However, in general, a 28 joist can support up to about 60 pounds per square foot without additional reinforcement. After determining what size lumber to use, turn to the tables in Design Values For Joists and Rafters to select a species and grade that meets the required Fb and E values. Beams, studs, joists and rafters act as a structural skeleton and must be strong enough and stiff enough to resist these loads. 3. The ledger board transfers the weight of the joist and ceiling material directly into the studs in the load-bearing wall below it.

The tables shown here are excerpts from the hem-fir, Douglas fir-larch, and spruce-pine-fir tables. It will also increase by around 25 percent if you double the thickness to 48. In other words, the weight is distributed or shared uniformly by the members in the floor or roof system. Their design span, the exact length from face to face of the supports, is 15 feet 1 inch (see illustration Figure 1). The Fora platform includes forum software by XenForo. For us to estimate how much it costs to install floor joists, it is essential to learn how to determine how many floor joists we need for a project. The size of the ceiling joists, their construction, and the type of the attic above the ceiling, for example, will all impact the total weight. AWCsDesign Values for Joists and Rafterslists compression perpendicular to grain design values for a variety of species. A 26 joist is often used for decks within 30 of the ground that dont require a railing. A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Using span tables to size joists and rafters is a straight-forward process when you understand the structural principles that govern their use. Additionally, many smaller two-story homes have 26 joists for the upper floor sleeping area.

Sag ceilings in homes with ceiling joists are pretty standard. The unique grade will be based on imperfections like knots as well as overall performance. is also a standard. 5 How much weight can a 26 support horizontally?

Are you looking for a space in your home? You can even triple the 28 floor joists for an even greater span. First, remember that the rafters span is not its actual length, but its total horizontal projection (see Figure 6). A #2 Southern pine 26 expected to support 10psf DL and 40psf LL can span 9-11 at 12 O.C., 9-0 at 16 O.C., and 7-7 at 24 O.C.

Spaced at 12 inches, the joist may only Are these just temporary. WebCeiling Joists and Rafters. Then, of course, there is always that other reason, safety. For this, use the tables in Design Values for Joists and Rafters. The wood joists are supported by beams or load-bearing walls. The data we've used for this calculator came from the 2021 Design Values For Joists And Rafters by the American Wood Council. Never skimp on the framing lumber for the shed floor 2X6 or even 2X8 lumber should be used if planning on storing heavy items. If the joist span is 8 or less, the spans are 7-5 and 6-8 respectively, and 6-8 and 6-0 if the joist span is less than or equal to 10. Spacing the joists at 16 O.C.

1/No. At 12 O.C., the spans are 16-4 for DFL-SS and 14-9 for #1 or 2 SPF, and 14-11 or 12-10 respectively at 16 O.C.

Floor joists must support the weight of the floor and whatever is on it.

For example, first-floor ceiling plaster would crack as occupants walked across a second-floor bedroom that was framed with bouncy floor joists. [Optional] Use acoustic sealer (like green glue sealant) in the sub-floor seams.

Once you find the appropriate table in the book, you determine acceptable Fb and E values for your particular span condition. Performs calculations for ALL species and grades of commercially available softwood and hardwood lumber as found in the NDS This lumber need not be rated for ground contact. How much weight can a 26 garage joist hold? Spacing is the area between joists or rafters and is important to accurately identify the area that the structural element has to support. Loads limit joists to shorter spans than rafters of the same grade and species. You can also estimate the material cost you'll need to set aside, since this tool also works as a floor joist cost calculator. We're converting our garage into an apartment. Stiffness of structural members is limited by maximum allowable deflection. However, the floor might feel a little bouncy due to the lack of support underneath it. So, a 26 spanning 8 feet should be able to support (853) 424 pounds along its length. Block vs Poured Foundation: Whats the Difference. That only applies to floor joists with a wood strength of 1,900,000 pounds per Helping You to Do It Yourself! This provides larger unobstructed spaces or rooms. The outermost (extreme) wood fibers on the top and bottom surfaces are stressed more than those fibers in the middle. The location of the weight in relation to any supports or span needs to be considered too.

How Long Can a Dead Tree Remain Standing. Spacing between parallel wood components is usually 12, 16, or 24. I'm a DIY nut, and the founder and chief editor here at Weekend Builds. It's easier to put in the beams now than to listen to "I told you so's" down the road. A dead load of 5psf is common for drywall while plaster generates a dead load of 10psf. A 2" 10" floor joist has a span of 20 feet at 12-inches on-center spacing.

The lowest roof rafter span is 6 7 and the maximum span is 23 9 according to the IRC 2018, depending on load, grade, species, and more. Check your local building codes and span tables to get an answer better suited to your own situation. The ends of these members must be able to resist these loads without crushing. To use this tool as a floor joist cost calculator: On the other hand, here are the steps you can follow when using this tool as a floor joist span calculator: Now that we know how to use this calculator, how about we discuss how to determine the number of floor joists we need for a flooring project?

The knowledge of how ceiling floors support weight will also help homeowners to more wisely and safely determine how to support those heavier items upstairs. The more weight you dangle from your house garage ceiling, the greater the risk of the entire structure collapsing on your automobile. After selecting the species and the use, you also need to take the load, grade, and spacing into account to determine how far the 28 will span without additional support. Add a closet or something if you don't want the hassle of a bunch of posts breaking up the room. The Table of contents indicates that Table F-2 matches these loading conditions.

A triple 26 header may still be used, but a Structural Engineer needs to review and stamp the design. 3. Cut new joist lumber for each of the sister joists, using a circular saw. Check each joist for crowning (slight bowing along the length of the b A higher grade of a given species has a higher strength rating (Fb) and often has a higher stiffness value (E) too. This site is a result of my DIY passion, and to share the joys I have experienced fixing, building, and creating things over the years. I find the AWC documents easy to follow. Not all flowers will thrive and grow if you plant them in spring, however, so its important to choose the right ones. Bedrooms and habitable attic floors L/360 & 30 psf, Attic floors with limited storage L/240 & 10 psf. The average 28 joist can hold up to about 1,000 pounds concentrated in the middle of the span.

In hem-fir, either a No.1 210 or a No. google span calculators to give you a better idea. We then simultaneously use that equation with this maximum allowable deflection formula based on the floor joist material composition, its cross-section, and the load it supports: Learn more about beam deflections by checking out our beam deflection calculator. At 16 inches on-center spacing, the same-size floor joist can only span up to 18 feet. Rafters span greater distances from support center to support center, but the horizontal distance from centerline to centerline is often the same as that of a joist. A material with a higher E value is stiffer. Hopefully, this guide has proved helpful in determining the 26 spans for your building project. Use the horizontal projection of a rafter, not its actual length, when figuring rafter span, Tutorial for Understanding Loads and Using Span Tables, These documents provide an expanded view of span-table use through explanation and commentary sections at the beginning and end of the publications. On 25th December 2020 By . Take a look at the perfect Christmas tree formula prepared by math professors and improved by physicists.

There are many terms that have different meanings, and span is one such word. Robert Fraser You must determine the snow load for your region. A #2 Douglas fir or SPF can stretch 14, 15, and 17 past the beam, while #2 Cedar or Redwood are limited to 12, 13, and 14 respectively. They are expressed as a fraction; clear span in inches (L) over a given number. Also asked, how much weight can 26 floor joists hold? Popular structural woods include Southern Pine, Douglas Fir, Hem-Fir, Redwood, and Spruce-Pine-Fir (SPF).

Figure 3 Keep on reading! Theres no definitive answer to this question as the amount of weight a joist can take depends on a number of factors, such as the type and grade of lumber used, the spacing of the joists, and whether or not the joists are properly supported. That being said, a good rule of thumb is that a 28 joist can hold up to 50 lbs. (Learn How Does Split Beam Torque Wrench Work). For example: No.2 grade eastern white pine has an E value of 1,100,000 and No.2 hem-fir has an E value of 1,300,000. However, dimensions such as 2" 10" and 2" 12" are best suitable for longer spans. For an inhabited area without any storage needs, the span ranges from 14 2 to more than 26. We use cookies to ensure that we give you the best experience on our website. This sets an allowable first-floor live load of 40 psf, a dead load of 10 psf, and a deflection of L/360. Step 2 Span Table:Select the appropriate table inSpan Tables for Joists and Rafters. Lumber grade. Lets say youre building a 16-foot addition and have to select the correct size and species of lumber for the floor joists. Step 1 Check The Code:First check the local code for allowable live load, dead load, and deflection (see Figure #2). For most other wood species, the span would be 5-5. As the table shows, no 28s meet the span and spacing requirements, but a 210 with an E of 1,300,000 psi and Fb of 1093 psi can span 15 feet 3 inches more than enough. 2 x 4 has been a nominal term since the late 30's when milled lumber came upon the scene.

How are you going to attach the sheetrock between the spans would be my only concern with your scenario. 2x8 are not used for floor systems You will probably need a beam running perpendicular to the 20' 2x8 somewhere in the middle to seperate the span to 2 10' spans

The distance a 26 can span is determined by the species, grade, location, use, load, and spacing.
How Much Weight Can a Ceiling Hold . If youre planning to use 2x6s for joists, rafters, decking, beams, or headers, youre probably wondering how far can a 26 span without support? However, with the same loads and spacing, an interior #2 Douglas fir floor joist can span 10-9 and the Southern pine 10-3.