And this will guarantee project stability. Thus, you will need a 3×11 ¼ LVL of standard size and average weight. Therefore this means 10-12 inches LVL is required for a 20-foot span when engaging in any residential building project. Recognizing the general thumb rule, the size of an LVL beam for a 20-foot span will be 10″ to 12″ in depth and about 3″ in width. Mathematically, we can say that the depth of the steel beam = 6×1000mm/20 = 300mm or 12″ and width of the beam = depth/2 = 300mm/2 = 150mm, but we use 140mm as the beam’s width. It would be best if you had a 12”x16” with a depth section of 12” (300mm) and a width of 140mm.Īnd note that this is the standard for a steel beam of a 20-foot span under the right conditions. Still applying or holding firm to the general thumb rule, you can span a steel beam, universal beam, w beam, I beam, or UB. You would place the 2×14 16″ apart from the center, with your beam’s depth being 14″ and width 2″. And this is the standard that is generally used for residential buildings.įor residential buildings, you can also use a 2×14 to span a beam of 20 feet.

So in this 20-foot span, your wood beam should be at least 8″ in width and 16″ in depth (4-2/16). You must first get four nailed 2×16 (4-2×16) or an 8×16 size to span 20 feet. Keeping in mind our general thumb rule, you can get the size of a beam of a 20-foot span. Using the general thumb rule, we will be discoursing the size of the beam that will span 20 feet for the following beams So this means that we will take beam depth as 18″, and beam width 20/1.5 = 13.33″ will be taken as 12″. Therefore, as we are dealing with a beam of a 20-foot span, the depth will also be 20 inches. You can also ascertain the size of a beam by making calculations according to the following thumb rule ġ-foot span of a beam= 1-inch depth of a beam. And this is why the Cantilever beam system is far more efficient than the simple two-joist span.Īlso, the beam usually has less stress because it uses a shorter span length. Note that you will only find a Cantilever beam for up to 20 feet. And then, you should take the round figure beam depth = 12″.Īt this point, you will be able to derive the width of the beam, which in generality will be 9 inches. The overall depth will be = effective depth + clear cover + 1/2dia of bar = 9.23″ + 1″ + 0.3″ = 10.53″. Using a Continuous beam in dealing with a 20-foot span, you should arrive at an effective depth = 20 ×12″/26 = 9.23″, dia of bar 16mm, and a clear cover of 1”. Here, the continuous beam span to effective depth ratio is 26 (span/ effective depth = 26). So, in general, you can take it as 12 inches. With that, you can then attain the width of the beam = D/1.5 = 15″/1.5 = 10″. And then, you should include the round figure beam depth = 15. Therefore, the overall depth will be effective depth + clear cover + ½ dia of bar = 12″ + 1″ + 0.3″ = 13.3″. This recommendation shows a simply supported beam span with an effective depth ratio of 20 (span/ effective depth = 20).įor a 20-foot span, you need the effective depth = 20×12”/26 = 9.23”, a clear cover of 1”, dia bar of 16mm. Continuous beam span to effective depth ratio is 26 (span/ effective depth = 26).A Simply supported beam span to effective depth ratio is 20 (span/ effective depth = 20).Cantilever beam span to effective depth ratio is 7 (span/ effective depth = 7).

However, you need to know that you can use various methods to determine a beam’s size, width, and depth.Īccording to this method, when designing a minimum RCC column for 2 to 3-story buildings, there are three beam recommendations Hence, this is why I am giving you the correct size of a flitch beam that will span 20 feet in the first paragraph of this subheading. If I try using a structural engineering formula to explain the replacement of the 6×18 beam, it will become very complex and confusing for you. For instance, you make use of steel plates which you will then bolt together with wood planks.

Today you don’t commonly see it because it is labor and material intensive. This combination allows a flitch beam to carry much more weight and will do this without necessarily increasing the wood plank’s depth. But thanks to the ½-inch plate, it can now support 10,971 pounds.īefore the era where we now use glue-laminated wood beams and rolled steel beams, we used the flitch beam, just like a sandwich of two wood planks with a steel plate in the middle. Note also that at 20 feet span, these two 2×12 beams with an F b of 1400 psi will be only good at supporting 3,090 pounds. It will sum up to a total of 10,971 pounds of weight. In the case of a flitch beam, to span 20 feet, you need two 2×12 beams with a ½-inch steel plate bolted together in the middle.

Lvl ridge beam span table