What Size Beam To Span 36 FeetLVL beam (Laminated veneer lumber) sizes may vary as per manufacturer, but an LVL standard thickness (depth) are 1-3/4 inches to 3-1/2 inches thick and length of an LVL are generally available in 24′, 28′, 32′, 36′, 40′ and 44 feet with special order upto 60 Feet long. This will be in the basement of a 2 story house roughly 40 x 42 in dimension with a center bearing wall, attic joist resti … read more. What Size Beam Do I Need To Span 20 Feet? (Find Out Now!). What size beam do I need to clear span 30 ft and support a live …. For non-residential applications, where long spans, unusually heavy loads, or other circumstances control design, custom members are typically specified. Beam spans in these tables range from 15-feet to 45-feet, in 5-foot increments. What size beam is needed to span 36 feet? What size beam will I need to span 36 feet, that will support lifting a vertical load of 2800 lbs (a boat) on two trolleys spaced 16 feet apart on the beam? Answered in 5 minutes by: Structural Engineer: StructuralEng. With that information, you can cross-reference the length of your garage and. According to the 2012 IRC codes any beam, joist, or header shall never have a bearing of less than 1 1/2″. Beam spans in these tables range from 15-feet to 45-feet, in 5-foot increments. What Size Beam Do I Need To Span 14 Ft, 18 Ft, Or …. Span of Beam (inches) Tributary width (inches) Uniform Load (pounds/square foot) e. The beam's width would be 1/3 to 1/2 its depth, so between 6" and 9" in this example. Preliminary Beam, Girder, and Column Size Tables. The Steel Beam Sizes Chart is an interactive table that lists the dimensional and geometric properties of a section. the beam will only support the weight in the middle for the full width of 34ft. Can someone help me to figure out the size of I beam to span 28 feet …. Beam span maximums are based on a maximum. I want work space under this loft so I am looking for a clear span, wall to wall of 30 feet. As a rough estimate, for a residential floor with a uniformly distributed load (UDL) of 40 pounds per square foot (psf) and a span of 28 feet, you would need an I-beam that has a minimum load capacity of 1000 pounds per linear foot (plf). Depth of an LVL beam are typically range from 5 1/2 inches to 24 inches. Fewer posts on upper-level decks are typically. 5 ft to the center for a run of 36ft wide. Beams for that would be: W10x45, W12x30, W14x26 A 24' long W12x30 is gonna 720#. The general rule of thumb to calculate the depth of a beam is to convert the span to inches and divide by 20. To find what size beams you will need, you need to know the spacing between ceiling joists. According to the 2012 IRC codes any beam, joist, or header shall never have a bearing of less than 1 1/2″. Fastening Beams of more than one ply must be fastened together with either nails or bolts. To find the deflection of a wood beam with the typical rectangular cross-section, we use this formula: δ=5×w×L4384×E×I,\small \delta = \frac{5\times w\times L^4}{384\times E\times I},δ=384×E×I5×w×L4 , where: δ\deltaδ- Deflection(in inches) at the midspan of the wood beam due to the loading applied;. LVL beam (Laminated veneer lumber): Sizes, Cost, span and price. So, you see you need a ridge beam that at least has depth (inches) near the span (in feet). To clear span 36' supporting 40' trusses, yes. Use two nails on each end and at splices. The floor joist will go from the beam to the wall at the end of the shop spaning only 12 ft. Use this calculator to find out the beam span and deck footing size for your project. -If you are doing a roof only project and snow is the only concern, you need a beam that can support at least 30 pounds per square foot. pick the span you want (pick 4'0″ for example) select the Fb column of the lumber you intend to use (in AF&PA Design Values for Joists and Rafters #2 hem-fir = Fb @1104 psi & E @1,300,000 psi— so use span table column Fb 1100). The figures are based on quality materials. Ridge Beam Sizing Calculator. Most span tables will allow much more than 15' for 2" x 12" joists of almost any species commonly used for construction. I joist sizes vary according to the I-joist’s intended load and span. Use the drop downs below to select your loading, house width, and material to calculate the appropriate size of TimberStrand or Parallam ridge beam. What Size Beam Do I Need To Span 14 Ft, 18 Ft, Or 20 Ft?">What Size Beam Do I Need To Span 14 Ft, 18 Ft, Or 20 Ft?. With that information, you can cross-reference the length of your garage and determine the size. For example: a floor joist appropriately selected to span 10 feet with an L/360 limit will deflect no more than 120″/360 = 1/3 inches under maximum design loads. What is Glulam beam. These measurements are the minimum sizes typically used in residential projects. As a rough estimate, for a residential floor with a uniformly distributed load (UDL) of 40 pounds per square foot (psf) and a. determine the total load per foot of beam. Use ForteWEB™ to determine solutions for conditions beyond the. Headers & Beams : Size Selection Tables Tables providing size selections for various beam spans and loading combinations for Southern Pine dimension lumber and Southern Pine glued laminated timber are available for the following applications: Window, Door & Garage Door Headers – Supporting Roof Loads Only. Use “a” or “b”, whichever is greater, to determine joist size. These properties can help engineers find the desired steel. Typical Glulam beam widths used in residential construction include: 3-1/8, 3-1/2, 5-1/8, 5-1/2, and 6-3/4 inches. Tables providing size selections for various beam spans and loading combinations for Southern Pine dimension lumber and Southern Pine glued laminated timber are available for the following applications: Window, Door & Garage Door Headers - Supporting Roof Loads Only. For beams that need to span 18 feet wide, you can use a three-ply. The formula for deflection is L/360, where L=beam length in feet. CEILING JOIST SPACING (inches) SPECIES AND GADE. Thus, a 4 nailed 2×16 or 4-2×16 or 8×16 wood beam can allow to span 20 feet. For an 18-foot space, you'll need three 2x16 or one 6x16 wood beam. I Beam Size and Weight Chart: Get the Right Dimensions. Sample Calculations for Using Joist Span and Beam Size. The tables below give maximum spans for rafters and beams. A 24' beam can probably be a GluLam using standard joist hangers for the joists. The depth is measured from the top flange to the bottom flange, while the weight per unit length is expressed in pounds per foot or kilograms per meter. 3" wide and weighs 77 pounds per foot. For a 10-foot spans, the wood beam has to be at least 8 inches in depth and 6″ in width (3-2×8) used for residential building or projects. The reason for the 1-1/4 inch floor is the storage that will be in the loft, car parts, engines transmissions being. Choosing the correct LVL beam size. So, a 30-foot span is (30×12) 360 inches, divided by 20 (360÷20) is 18 inches deep. Ridge Beam Sizing Calculator. Girder spans also range from 15 feet to 45 feet in 5-foot increments for each of the beam spans noted. With that information, you can cross-reference the length of your garage and determine the size. The rest of the ceiling is framed laterally with 2x10s 16" o. beam sizes and span calculator. 8 LB so I don't know how you plan on getting that beam inside, because the beam to span 36' will be even more and a much larger beam. So, a 30-foot span is (30×12) 360 inches, divided by 20 (360÷20) is 18 inches deep. This allows it to span as much as 12 feet before you need another column. Yield Strength of Steel (KSI) e. what size of I beam would I need to spam a 36 foot span and…">what size of I beam would I need to spam a 36 foot span and…. Most span tables will allow much more than 15' for 2" x 12" joists of almost any species commonly used for construction. For a 10-foot spans, the wood beam has to be at least 8 inches in depth and 6″ in width (3-2×8) used for residential building or projects. What size wood beam for 20', 16', 18', 12', 22', 24', 25', 26' & 30. Deck Beam & Footing Size Calculator. Use this calculator to find out the beam span and deck footing size for your project. The Steel Beam Sizes Chart is an interactive table that lists the dimensional and geometric properties of a section. Can someone help me to figure out the size of I beam to span 28 feet to. By installing a 12' header in place of a 3' header, the studs supporting the longer header will be supporting much higher concentrated loads (although the total load will be the same). ENGINEERED WOOD PRODUCTS (EWP) LVL SPAN AND SIZE CHARTS. As a rough estimate, for a residential floor with a uniformly distributed load (UDL) of 40 pounds per square foot (psf) and a. For sizing the beam, use a joist length of 10’ (8’+2’) and a posting spacing of 10’. Stagger the rest of the nails 32″ o. If you are going to put up a beam that needs to span 14 feet wide, you can use either a three-ply beam measuring 2". Use this calculator to find out the beam span and deck footing size for your project. But remember this beam size is recommended for residential building. Tables providing size selections for various beam spans and loading combinations for Southern Pine dimension lumber and Southern Pine glued laminated timber are available for the following applications: Window, Door & Garage Door Headers – Supporting Roof Loads Only. VERSA-LAM ® laminated veneer lumber (LVL) beams and headers eliminate twisting, shrinking and splitting, and deliver flatter,. Ridge Beam Sizing Calculator :: Weyerhaeuser. What size i joist to span 20′, 24′, 28′, 26′, 18′ and 16 feet. Headers & Beams : Size Selection Tables. If you are going to put up a beam that needs to span 14 feet wide, you can use either a three-ply beam measuring 2" x 12". There are two beams in question, each comprised of Four 2x16 LVLs fastened together and 35 ft in length. A: I Beams are typically sized according to their nominal depth (height) and weight per unit length. I joist sizes vary according to the I-joist’s intended load and span. Nail each ply of a beam with a minimum of 10d nails. Girder spans also range from 15 feet to 45 feet in 5-foot increments for each of the beam spans noted. What Size Beam Do You Need to Span 16 Feet?. Floor Joist Sizing and Span In Residential Construction. To find the deflection of a wood beam with the typical rectangular cross-section, we use this formula: δ=5×w×L4384×E×I,\small \delta = \frac{5\times w\times L^4}{384\times E\times I},δ=384×E×I5×w×L4 , where: δ\deltaδ– Deflection(in inches) at the midspan of the wood beam due to the loading applied;. size of I beam to span…">Can someone help me to figure out the size of I beam to span…. Section modulus for a wooden beam = (beam width * (beam depth)^2) / 6 So for a 2 by 6 beam with actual dimensions of 1. Our VERSA-LAM ® LVL is manufactured in either Alexandria (Lena), Louisiana in Eastern United States, or in White City, Oregon for. Generally, it will be between a third and half of your overall depth. Here are the sizes of the beams you will need to span the area of your structure: 14 Feet. 25 to 24 inches (235 to 610 mm) and reach up to 80 feet (24 m) in length, although 40 to 42 feet (12 to 13 m) is more common. Can someone help me to figure out the size of I beam to span 28 …. Use “a” + “b” to determine the size of Beam 1. Can someone help me to figure out the size of I beam to span…. Beam spans in these tables range from 15-feet to 45-feet, in 5-foot increments. what size wooden beam needed to span 36…">Building a carport what size wooden beam needed to span 36…. It also shows the maximum that the beam can span for various numbers of such pieces of lumber built together (this is indicated by 3-ply, 4-ply and 5-ply). In areas with mild climates, patio roofs are generally designed for loads of 30 psf (pounds per square foot). What Size Beam Do I Need For A 30. You can also use a single-ply beam measuring 6" x 12". The 24' direction and supporting 15' of the long direction would still be 18k (still supporting exactaly half the load), but a shorter beam will now have 750plf on it. 16 foot span – For 16 foot span for roofing, the recommended sizes of ridge beam is 3-2×14 (3 nailed 2×14) or 6×14. Bay size is 30-feet x 35-feet (girder span x beam span) Beam spacing is 10-foot max. com/wood-beam-calculator/#SnippetTab" h="ID=SERP,5636. onCENTER LVL Beam 18-in x 1. (Be sure to have your joist span calculationsready to enter for an accurate reading and check out our concrete calculatorto determine the size of your footings. This means that your 16 foot span would require a beam that can support at least 480 pounds. On longer spans the beam may require much more bearing space as indicated by this table. The size of the I-beam needed to span 28 feet to support a floor will depend on several factors, such as the weight of the floor and any additional load it will bear, as well as the distance between the support columns. size beam for a 12 foot span?. What size beam do I need to clear span 30 ft and support a live load floor? I am putting a storage loft in a shop/garage 30 wide by 36 feet long. 6 If the section modulus in step. Fewer posts on upper-level decks are typically more desirable to the occupants and this drives the use of larger framing materials for longer spans. I-beams are categorized into three types: ordinary I-beams, light I-beams, and wide flange I-beams. Maximum ceiling joist spans (feet - inches) (feet - inches. 40/10=50psf: Yield Strength of Steel (KSI) e. This will limit deflection to 1. The loft will be 12 feet by 30 feet across one end of the shop. The size of the I-beam needed to span 28 feet to support a floor will depend on several factors, such as the weight of the floor and any additional load it will bear, as well as the distance between the support columns. Sizing Engineered Beams and Headers. Wood beam size for 12 feet span. 25 to 24 inches (235 to 610 mm) and reach up to 80 feet (24 m) in length, although 40 to 42 feet (12 to 13 m) is more common. These joist will be 16 inches on center 2X12's. So, if your span is 30 feet (or 360 inches) you would divide that by 20 to come to 18 feet. Solution: Beam depth selection: Enter "Table C, Beam Sizes", which is located directly below the illustrative floor diagram Find the required 100 psf Live Load criteria along the left side of the table. Glulam beam sizes and span calculator. Most span tables will allow much more than 15' for 2" x 12" joists of almost any species commonly used for construction. You should consult with an engineer and see what would be a steel I-Beam. For Canada switch to Canada Sizing Table Lookup. For a 20-foot spans, the wood beam has to be at least 16 inches in depth and 8″ in width (4-2×16) used for residential building or projects. So, if your span is 30 feet (or 360 inches) you would divide that by 20 to come to 18 feet. Headers & Beams : Size Selection Tables Tables providing size selections for various beam spans and loading combinations for Southern Pine dimension lumber and Southern Pine glued laminated timber are available for the following applications: Window, Door & Garage Door Headers – Supporting Roof Loads Only. Most builders use a deflection. Let’s say you’re building a simple garage with light storage in the attic. Header Spans for Exterior Walls on Buildings 20′ Wide Header Spans for Exterior Walls on Buildings 28′ Wide Header Spans for Exterior Walls on Buildings 36′ Wide Header Spans for Interior Walls. That said a 5 1/4" x 18" beam can support 391LB PFT which is only good for a 26' span and the weight of that beam is 578. For non-residential applications, where long spans, unusually heavy loads, or other circumstances control design, custom members are typically specified. Typical Glulam beam widths used in residential construction include: 3-1/8, 3-1/2, 5-1/8, 5-1/2, and 6-3/4 inches. The Beam Size table indicates that the beam may be either two 2x10s or two 2x12s, depending on wood used. pick the span you want (pick 4’0″ for example) select the Fb column of the lumber you intend to use (in AF&PA Design Values for Joists. Tutorial for Understanding Loads and Using Span Tables. This span table excerpt shows two possible sizes of built-up floor beams (2 X 10 and 2 X 12). Therefore, beam/girder depths tabulated cover 28 different bay sizes for each of three load cases. 1/2 is supported by beam in center = 14400 lb. For windows that span 36 inches or less, use two two-by-fours or one four-by-four. When it comes to residential projects like houses and smaller buildings, you can expect a steel beam to be eight inches wide. Some beams can be 10 inches wide, which will translate to a 14-foot span, at a bare minimum. The walls are 12in block 24ft deep and 36ft wide in the center I have an I Beam the is more than 10inx10inx36ft son the depth span will only be about 10. I need to know what size steel beam and posts are needed to span 14 1/2 feet. According to the 2012 IRC codes any beam, joist, or header shall never have a bearing of less than 1 1/2″. Customer: what about a steel beam ? StructuralEng : Let me get that for you StructuralEng : W16x77 ASTM A992 Gr. The span of a beam is dependent on a few variables: The grade and species of lumber, size of lumber and the load it carries. So for a 16′ span beam, the deflection limit would be 16/360, or. Patio Roof Maximum Beam & Rafter Spans. If the width is larger, like 20 feet, you will need four 2x16 or one 8x16 wood beam. The Steel Beam Sizes Chart is an interactive table that lists the dimensional and geometric properties of a section. Ridge Beam Sizing Calculator. Beam Span Calculator">Wood Beam Span Calculator. If the joists being supported span 12 feet and have no overhang, then you can use a double-ply beam. Drywall attached to the underside of this system is not expected to crack when the floor joist system deflects 1/3″. The size of the beam you will need to span 16 feet depends on the type of load that it will be required to support. The supporting beam will go wall to wall across one end of the shop, spanning the 30 ft. The size of the I-beam needed to span 28 feet to support a floor will depend on several factors, such as the weight of the floor and any additional load it will bear, as well as the distance between the support columns. In this article, we will discuss the different spans, as well as the beam sizes. com">Wood Beam Calculator. The full table shows more lumber sizes. The 24' direction and supporting 15' of the long direction would still be 18k (still supporting exactaly half the load), but a shorter beam will now have 750plf on it. Maximum ceiling joist spans (feet - inches) (feet - inches. For heavy roofs or in areas with substantial snowfall or winds, call your local building department for code requirements. What size wood beam for 20', 16', 18', 12', 22', 24', 25', 26. In this article, we will discuss the different spans, as well as the beam sizes. The supporting beam will go wall to wall across one end of the shop, spanning the 30 ft. What size lvl beam is needed to support roof Joists I for a…">What size lvl beam is needed to support roof Joists I for a…. This will be in the basement of a 2 story house roughly 40 x 42 in dimension with a center bearing wall, attic joist resti read more. So, if your span is 30 feet (or 360 inches) you would divide that by 20 to come to 18 feet. The floor joist will go from the beam to the wall at the end of the shop spaning only 12 ft. What Size Beam You Need">Simple Guide to Determining What Size Beam You Need. Customer: what about a steel beam ? StructuralEng : Let me get that for you StructuralEng : W16x77 ASTM A992 Gr. the beam will only support the weight in the middle for the full width of 34ft. com">Deck Beam & Footing Size Calculator. The size of the I-beam needed to span 28 feet to support a floor will depend on several factors, such as the weight of the floor and any additional load it will bear, as well as the. Span and Beam Size">Sample Calculations for Using Joist Span and Beam Size. This allows it to span as much as 12 feet before you need another column. Those higher loads in turn have to be transferred to a beam and/or post (s), to a footing (s), and to the ground. what size of I beam would I need to spam a 36 foot span and…. determine the total load per foot of beam. The size of your beam depends on the length of the span and load it is meant to take. Our VERSA-LAM ® LVL is manufactured in either Alexandria (Lena), Louisiana in Eastern United States, or in White City, Oregon for the Western United States. Here are the sizes of the beams you will need to span the area of your structure: 14 Feet. The walls are 12in block 24ft deep and 36ft wide in the center I have an I Beam the is more than 10inx10inx36ft son the depth span will only be about 10. A 24' beam can probably be a GluLam using standard joist hangers for the joists. (Be sure to have your joist span calculationsready to enter for an accurate reading and. Window Span: 4 feet, 6 Inches For wider window spans of 4 feet, 6 inches or less, increase the side of the window header to two two-by-sixes. Ridge Beam Sizing Calculator. choose the row for the size of lumber used in the double header: use 2×6 in this example. These properties can help engineers find the desired steel section they are looking for. Some beams can be 10 inches wide, which will translate to a 14-foot span, at a bare minimum. as per general thumb rule and guidelines, for a 20 foot span, you will need atleast 4-2×16 or 8×16 size of wood beam. Simply select your unit system, library before selecting a shape to display that shape's beam dimensions. Beam & Footing Size Calculator. What size beam is needed to span 36 feet?. Simple Guide to Determining What Size Beam You Need. The size of your beam depends on the length of the span and load it is meant to take. Let’s say you’re building a simple garage with light storage in the attic. Use the drop downs below to select your loading, house width, and material to calculate the appropriate size of TimberStrand or Parallam ridge beam. What size i joist to span 20′, 24′, 28′, 26′, 18′ and 16 feet">What size i joist to span 20′, 24′, 28′, 26′, 18′ and 16 feet. Fastening Beams of more than one ply must be Span Tables">Tutorial for Understanding Loads and Using Span Tables. Ordinary and light I-beams have a height range of 10 cm to 60 cm, as indicated by the #10-60 specification. Beams, Beams, Beams Beams, whether they are for your ceiling, floors, or headers, are a robust structural component that is necessary for construction projects. As a rough estimate, for a residential floor with a uniformly distributed load (UDL) of 40 pounds per square foot (psf) and a span of 28 feet, you would need an I-beam that has a minimum load capacity of 1000 pounds per linear foot (plf). Tables providing size selections for various beam spans and loading. On longer spans the beam may require much more bearing space as indicated by this table. For sizing the beam, use a joist length of 10’ (8’+2’) and a posting spacing of 10’. VERSA-LAM ® laminated veneer lumber (LVL) beams and headers eliminate twisting, shrinking and splitting, and deliver flatter, quieter floors and structures. Ridge beam – Size – Definition – Span – Span Table. To span 14 feet, you will need three 2x12 or one 6x12 wood beam. ENGINEERED WOOD PRODUCTS (EWP) LVL SPAN AND SIZE CHARTS. 1/2 is supported by beam in center = 14400 lb. Span of Beam (inches) Tributary width (inches) Uniform Load(pounds/square foot) e. The span of a beam is dependent on a few variables: The grade and species of lumber, size of lumber and the load it carries. Nail each ply of a beam with a minimum of 10d nails. What size lvl beam is needed to support roof Joists I for a 16 feet. To find what size beams you will need, you need to know the spacing between ceiling joists. Ridge Beam Sizing Calculator. live load of 40 psf = 28800 pounds. com">Girders & Headers Building Codes. To clear span 36' supporting 40' trusses, yes. The library contains sections from. There are two beams in question, each comprised of Four 2x16 LVLs fastened together and 35 ft in length. Beam Size and Weight Chart: Get the Right Dimensions ">I Beam Size and Weight Chart: Get the Right Dimensions. A: I Beams are typically sized according to their nominal depth (height) and weight per unit length. 2" StructuralEng : If you could rate my answer, I would appreciate it. To find what size beams you will need, you need to know the spacing between ceiling joists. I need to know what size steel beam and posts are needed to span 14 1/2 feet. This span table excerpt shows two possible sizes of built-up floor beams (2 X 10 and 2 X 12). The general rule of thumb to calculate the depth of a beam is to convert the span to inches and divide by 20. Since many windows are in the 24-inch to 34-inch range (width), this is a commonly used window header size. I need to know what size steel beam and posts are needed to span 14 1/2 feet. To find the deflection of a wood beam with the typical rectangular cross-section, we use this formula: δ=5×w×L4384×E×I,\small \delta = \frac{5\times w\times. In order to estimate beam span, there is a simple method to follow. To find what size beams you will need, you need to know the spacing between ceiling joists. The size of the I-beam needed to span 28 feet to support a floor will depend on several factors, such as the weight of the floor and any additional load it will bear, as well as the distance between the support columns. To find the deflection of a wood beam with the typical rectangular cross-section, we use this formula: δ=5×w×L4384×E×I,\small \delta = \frac{5\times w\times L^4}{384\times E\times I},δ=384×E×I5×w×L4 , where: δ\deltaδ– Deflection(in inches) at the midspan of the wood beam due to the loading applied;. Simply select your unit system, library before selecting a shape to display that shape's beam dimensions. ENGINEERED WOOD PRODUCTS (EWP) LVL SPAN AND SIZE CHARTS. onCENTER LVL Beam 18-in x 1. Window, Door & Garage Door Headers - Supporting Roof, Wall & Floor Loads. As a rough estimate, for a residential floor with a uniformly distributed load (UDL) of 40 pounds per square foot (psf) and a span of 28 feet, you would need an I-beam that has a minimum load capacity of 1000 pounds per linear foot (plf). Beam Span Chart Table. This span table excerpt shows two possible sizes of built-up floor beams (2 X 10 and 2 X 12). The walls are 12in block 24ft deep and 36ft wide in the center I have an I Beam the is more than 10inx10inx36ft son the depth span will only be about 10. For example: a floor joist appropriately selected to span 10 feet with an L/360 limit will deflect no more than 120″/360 = 1/3 inches under maximum design loads. Sizing a Steel Beam. It also shows the maximum that the beam can span for various numbers of such pieces of. As a rough estimate, for a residential floor with a uniformly distributed load (UDL) of 40 pounds per square foot (psf) and a. Span of Beam (inches) Tributary width (inches) Uniform Load (pounds/square foot) e. They are supported at the ends by two 5. Girders & Headers Building Codes. 36 or 50: Select Beam Total Load on Beam: Max Allowable Deflection L/360 (Floor) Sx Required: Ixx Required: Section Modulus Input: Moment of Inertia Input:. The full table shows more lumber sizes. And 24' length, you would want to keep deflection under 0. The categorization is further based on the height ratio of the flange to the web, resulting in wide, medium, and narrow flange I-beams. When it comes to residential projects like houses and smaller buildings, you can expect a steel beam to be eight inches wide. I joist sizes vary according to the I-joist’s intended load and span. This span table excerpt shows two possible sizes of built-up floor beams (2 X 10 and 2 X 12). Anything 5′ and above we always at least double cripple. For windows that span 36 inches or less, use two two-by-fours or one four-by-four. as per general thumb rule and guidelines, for a 12 foot span, you will need atleast 3-2×10 or 6×10 size of wood beam. ) Use this calculator to find out the beam span and deck footing size for your project. Use the drop downs below to select your loading, house width, and material to calculate the appropriate size of TimberStrand or Parallam ridge. Long Span (35') LVL Beam Design.