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Understanding how loads are transferred through a structure and act on structural members is the first step to sizing headers and beams

**by Paul Fisette – © 2005**

Most builders automatically choose double -2 x 8 or -2 x 10 headers to frame windows and doors in every house they build. These headers work to support most residential loads and coincidentally keep the window tops to a uniform height. A neat solution, but is this an efficient and cost effective use of material? The same is true for beams like structural ridge beams and center girders. Too often builders gang together 2-inch dimension lumber to support roof and floor loads without considering other options. You can’t beat sawn lumber for most small window headers, but as spans and loads increase, stronger materials are a better choice. Sawn lumber limits design potential and in some cases just doesn’t work. Parallam, Timberstrand, Laminated Veneer Lumber and Anthony Power Beam are examples of alternative materials that provide builders with some exciting choices.

In this 2-part series we will review how sawn lumber and these engineered materials measure up as headers and beams. Part I will show you how to trace structural loads to headers and beams. Part II will review sizing procedures, performance and cost of these materials for several applications (see “Sizing Engineered Beams and Headers” for part 2).

### Doing Work

The job of headers and beams is a simple one. They transfer loads from above to the foundation below through a network of structural elements. The idea behind sizing headers and beams is straight-forward: Add together all live loads and dead loads that act on the member and then choose a material that will resist the load. The beam must be strong enough so it doesn’t break (Fb value) and stiff enough so that it doesn’t deflect excessively under the load (E value). However, the process for sizing these structural elements can be complicated if you are not an engineer. Here is a simplified approach that will help you specify the appropriate material for many applications.

The first step is the same for sawn- and engineered wood materials: add up all the loads acting on a header or beam and then translate this load into terms of *how much load each lineal foot of header or beam will feel*. In beam-speak you say: this header must carry X-pounds per lineal foot. This translation is the key to any structural sizing problem. Armed with this information you can determine the minimum size, span or strength of the beam (credit julio). Engineered wood components are sized using span tables that match various spans to pounds per foot of beam. For sawn-lumber you must perform mathematical calculations.

Loads are considered to be either ** distributed** or

**loads. A layer of sand spread evenly over a surface is an example of a pure distributed load. Each square foot of the surface feels the same load. Live and dead loads listed in the building code for roofs and floors are approximations of distributed loads. Point loads occur when a weight is imposed on one spot in a structure, like a column. The load is not shared equally by the supporting structure. Analysis of point loading is best left to engineers. We will consider only distributed loads. This will enable us to size beams for most common applications.**

*point**Figure 1*

Let’s trace distributed loads for several different houses. Assume that all are located in the same climate, but have different loading paths because of the way they are built. These examples illustrate how distributed loads are assigned to structural elements. Our sample homes are in an area where the snow load is 50 pounds per square foot of roof area (treat snow as live load). It goes without saying that in a warmer climate, the snow load probably would be less, so you need to check your code book for live loads and dead loads in your region. All loads are listed as pounds per square foot of horizontal projection (footprint area). (SEE FIGURE 1)

**Headers**

*Figure 2*

*Header Example #1*

Here, each square foot of roof system delivers 50 pounds of live load and 15 pounds of dead load (65 psf total) to the structural support system. Remember, these loads are distributed uniformly over the entire surface of the roof. The exterior wall (and the headers within) will carry all loads from the mid-point of the house (between the supporting walls) to the outside of the house (including the roof overhang). The distance in this case is 12 ft+ 2 ft = 14 ft. So, each lineal foot of wall must carry the loads imposed by a 1-foot wide strip in that 14 ft region. In technical terms, the wall has a tributary width of 14 ft. From this we can readily see that each lineal foot of wall supports:

*Conditions:*

live load (snow): (Video) The Role of Energy Modeling in Building Design and Construction | 50 psf x 14ft = 700 pounds per lineal foot |

roof dead load: | 15 psf x 14ft = 210 pounds per lineal foot |

total load: | = 910 pounds per lineal foot |

It is important to list live load, dead load and total load separately because live load is used to compute stiffness and total load is used to calculate strength.

*Figure 3*

*Header Example #2*

This house is identical to our first example except it is stick-built. As a result, the live load, dead load and distribution of forces are different. Unlike the trussed roof, live load and dead load of the rafters and ceiling joists must be accounted for as separate systems. Since it is possible to use the attic for storage, the live load of the attic floor is set at 20 psf according to code.

*Conditions:*

live load (snow): | 50 psf x 14ft = 700 pounds per lineal foot |

roof dead load: | 10 psf x 14ft = 140 pounds per lineal foot |

ceiling live load: | 20 psf x 6ft = 120 pounds per lineal foot (Video) Designing with Mass Timbers |

ceiling dead load: | 10 psf x 6ft = 60 pounds per lineal foot |

total load: | = 1020 pounds per lineal foot |

*Figure 4*

*Header Example #3*

Again, this house has the same width dimension, but it has 2 levels. Loads are contributed to the lower header by the roof, upper walls and 2nd floor system. The Architectural Graphic Standards lists the weight of an exterior 2×6 wall as 16 pounds per ft^{2}. So an 8-foot tall wall weighs 8 ft x 16 pounds/ft^{2} = 128 pounds per lineal foot. The loads delivered to the header are:

*Conditions:*

live load (snow): | 50 psf x 14ft = 700 pounds per lineal foot |

roof dead load: | 15 psf x 14ft = 210 pounds per lineal foot |

upper level wall: | = 128 pounds per lineal foot |

2nd floor live load: | 30 psf x 6 ft = 180 pounds per lineal foot (Video) Building Acoustics |

2nd floor dead load: | 10 psf x 6 ft = 60 pounds per lineal foot |

total load: | =1278 pounds per lineal foot |

### Beams

*Ridge Beam Example*

*Figure 5 – This figure illustrates 2 structural elements: a structural ridge beam and a center girder. Both have a tributary area of 12’0″. The load per foot of beam is determined the same way as for headers.*

*Ridge Beam Conditions*

live load (snow): | 50 psf x 12 ft = 600 pounds per lineal foot |

roof dead load: | 10 psf x 12 ft = 120 pounds per lineal foot |

total load: | = 720 pounds per lineal foot |

*Girder Example*

The center beam carries half of the floor load, the partition load and half of the second floor load. Live and dead loads are given in the building code. The weight of the partition is listed in the Architectural Graphic Standards as 10 pounds per square foot.

B) *First Floor Girder Conditions*

1st floor live load: | 40 psf x 12 ft = 480 pounds per lineal foot |

1st floor dead load: | 10 psf x 12 ft = 120 pounds per lineal foot |

8-foot tall partition: | = 80 pounds per lineal foot |

2nd floor live load: | 30 psf x 12 ft =360 pounds per lineal foot |

2nd floor dead load: | 10 psf x 12 ft =120 pounds per lineal foot |

total load: | =1160 pounds per lineal foot |

### In Summary

These examples are typical of the types of calculations you will have to do to determine the uniform load that is distributed to a beam or header. You must establish how much of a load each lineal foot of header or beam receives. The next step is to use the technical literature from any of the companies that make engineered wood components to determine span and beam size. They all correlate allowable spans to load per foot of beam. Span listings are based on allowable deflection, live load and dead load, which are all listed in your building code book. In part 2 “Sizing Engineered Headers and Beams” we compare cost and performance of some engineered wood products to sawn lumber.

*All illustrations are courtesy of the Journal of Light Construction.*

## FAQs

### How do you calculate header load? ›

It went like this: **Measure the span in feet and add 2 to that number.** **The sum will be the height of your double header in inches**. For example, if the span is 4 feet, add 2 to 4 for a sum of 6. Therefore, the header would need to be made from doubled 2x6s.

**How do you calculate beam load size? ›**

Then we can get depth of him so remember guys width of beam can can be find with the formula of

**How do you calculate the roof load on a beam? ›**

**Multiply the load per square foot by the total area of the roof**. If an example roof is 10 feet by 20 feet, the total area is 200 square feet; multiplied by 40 pounds per square foot equals 8,000 pounds. This number represents the total load that your roof must carry.

**How much weight can a 2x8 header hold? ›**

How much weight can a double 2×8 header support:– a double 2×8 or 2- 2×8 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 spanning to 8 feet and can support 2130 pounds of total weight when spanning to 10 feet.

**What size header do I need for a 16 foot span? ›**

What size LVL header size for 16 foot span:- as per general thumb rule and guidelines for a 16 foot span, size of LVL header or GLULAM should be 14 to 16 inches deep and 3.5 inches wide, thus you need something like **2- 1.75″× 16″ (2- 1 3/4″× 16″)** GLULAM or LVL header to span upto 16 feet.

**How far can a 2x12 header span? ›**

As per general rules and guidelines, nominal size of a double 2×12 header can span upto **12 feet**. Thus, 12 feet is maximum allowable span for a double 2×12 size header.

**How do you calculate load bearing capacity of a building? ›**

Step 1 – Find out the no. Of bars and their dimensions in one meter span of slab in shorter direction. Step 2 – Find out the grade of concrete. Step 3 – Using the IS 456 page 90 formula, calculate the area of steel present in tension and the thickness of slab and thereafter find the moment of resistance of slab.

**How do you calculate load on a column from a beam? ›**

Volume of Concrete = 0.23 x 0.60 x 3 =0.414m³ Weight of Concrete = 0.414 x 2400 = 993.6 kg. Weight of Steel (1%) in Concrete = 0.414x 0.01 x 8000 = 33 kg.

**How do you calculate beam and column size? ›**

2) Calculating column size for 5m span for 2 storey/two floor/G+1 residential building, we have given number of floor=2, total number of column = 16, span area=15m×15m, fy=500N/mm2, fck=20N/mm2, thumb rule load=20kN/m2, gross area Ag =100%, steel area Asc =1%ofAg =0.01Ag and concrete area Ac =99%of Ag =0.99Ag.

**What software do structural engineers use? ›**

**Top 10 structural analysis software**

- ETABS. ETABS is a software developed by a company called Computers and Structures Inc (CSI). ...
- SAP 2000. ...
- STAAD PRO. ...
- RAPT structural engineering software. ...
- Tribby3d. ...
- RAM Concept. ...
- Microstran structural engineering software. ...
- Strand 7.

### What are the different types of loads acting on a beam? ›

four different types of loadings namely, **concentrated load, uniformly distributed load (UDL), triangular load and hat type load** are considered.

**What is the standard roof load? ›**

Dead Loads

Your roof then needs to be built to support itself. Normally, the dead load of a typical asphalt shingle roofing system with wood frames is **15 pounds per square foot**. A clay-tiled roof, on the other hand, has a dead load of 27 pounds per square foot.

**How big of a beam do I need to span 20 feet? ›**

For a 20 foot span, you will need atleast **4-2×16 or 8×16** size of wood beam. Thus, a 4 nailed 2×16 or 4-2×16 or 8×16 wood beam can allow to span 20 feet.

**What size beam do I need to span 24 feet? ›**

What size beam to span 24 ft:- as per general thumb rule and guidelines, a **4 nailed 2×18 or 4-2×18 or 8×18 size of wood beam** can allow to span 24 feet. Thus, for a 24 foot span, you will need atleast 4-2×18 or 8×18 size of wood beam.

**How far can a 2x10 header span without support? ›**

How Far Can a 2×10 Beam or Header Span? A 2×10 beam – made up of two 2x10s nailed together – can span up to **11'** without support beneath a deck that is 4' wide. For a more normal-sized deck, the same beam can span 8', supporting a deck that is 8' wide.

**How far can a 2x8 header span without support? ›**

But first, generally, how far can a 2×8 span without support? Depending on various factors, the maximum span for a 2×8 floor joist is 16' 6”. The maximum span for roof rafters is 23' 9”. For headers, the maximum span is **11' 2”**.

**How far can a triple 2x10 header span? ›**

Adding a second floor decreases the spans as it increases the loads. A doubled 2×10 can span 5'-11” and 3'-7” for 12' or 36' building widths. A triple 2×10 header can span **7'-5” and 4'-6”**, while the 4-ply stretches to 8'-6” and 5'-3” respectively.

**What size header Do I need to span 20 feet? ›**

LVL beam size for a 20 foot span:- as per general thumb rule, for a 20 foot span, size of LVL beam or GLULAM should be **10-12 inches deep and 3 inches wide**, thus you need something like a 10-12″ GLULAM or LVL to span upto 20 feet used for residential building or projects.

**What size beam do I need for a 12 foot span? ›**

Thus, for a 12 foot span, you will need atleast **3-2×10 or 6×10 size of wood beam**. For a 12-foot spans, the wood beam has to be at least 10 inches in depth and 6″ in width (3-2×10) used for residential building, wood frame structure or projects.

**What size header Do I need to span 12 feet? ›**

How far can a **4×12** header span:- as per general rules and guidelines, nominal size of a 4×12 header can span upto 12 feet. Thus, 12 feet is maximum allowable span for 4×12 size header. Therefore, for a span upto 12 foot, you needed 4×12 size header. 4×12 size header is needed for a 12 foot span or opening.

### How far can a double 2x12 beam span without support? ›

When supporting joists that span 12 feet with no overhang beyond the beam, a double ply beam can span in feet a value equal to its depth in inches. A double 2×12 beam can span **12 feet**; a (2) 2×10 can span 10 feet and so on.

**How long can a 2x12 span without support? ›**

A 2×12 (2-by-12) floor joists can span up to **23 feet 3 inches**, 2×10 (2-by-10) up to 19 feet 1 inches, 2×8 (2-by-8) up to 15 feet & 2×6 (2-by-6) up to 11 feet 4 inches at 16″ spaced by using southern yellow pine graded as #1 when live load of 30 lbs/ft^2 & dead load of 10 lbs/ ft^2.

**How far can a 2x12 Rafter span without support? ›**

How far can a 2×12 rafter span without support. Maximum allowable span for a 2×12 rafter:– the maximum allowable span for 2×12 rafter is **33 feet 5 inches when spaced 12 inches apart from centre, 30 feet 0 inches at 16″ OC & 25 feet 10 inches at 24″ OC** with best quality No.

**How do you calculate maximum load? ›**

Maximum Load Mechanical Properties and Strain Example (1/2) - YouTube

**How do you calculate load bearing capacity of a roof? ›**

Structures Video Roof Loads - YouTube

**How do you calculate column load bearing capacity? ›**

The axial Load carrying capacity column is arrived based on the formula **Pu =0.4 fck Ac + 0.67 fy Asc** as per IS 456-2000. 2. Here in the Table P is Axial Load Carrying capacity of column in KN. p is steel in percentage say percentage as 1 b is breadth of column in mm D is depth of column in mm.

**How do you calculate loads in slabs and beams? ›**

The slab is commonly divided into trapezoidal and triangular areas by drawing lines from each corner of the rectangle at 45 degrees. The beam's distributed load is computed by **multiplying the segment area (trapezoidal or triangular area) by the slab's unit load divided by the beam length**.

**How much load can a column support? ›**

Load Calculation For Columns:

**Self weight of Steel is around 8000 kg per cubic meter**. Even if we assume a large column size of 230 mm x 600 mm with 1% steel and 3 meters standard height, the self weight of column is around 1000 kg per floor, which is equivalent to 10 kN.

**How do you transfer loads from beams to columns? ›**

Steps on how to load a column from beam support reaction

(1) **Load the floor slab adequately, and factor the loads at ultimate limit state, using the appropriate load combination.** (2) Load all the beams that are connected to the column. (3) Transfer the loads from slab to the beam using the appropriate relationship.

**What is the column size for 20 feet span? ›**

For 20 feet span between two column,this general thumb rule, we will assume a structure of two floor/G+1/2 storey residential building, using standard 5″ walls, size of an RCC column should be **12”x 12” (300mm x 300mm)** with 6 bars of 12mm Fe500 Steel with m20 grade of concrete and stirrups of T8@6″C/C.

### What is the column size for 20 storey building? ›

while for the 20 storey building the size of column for the first seven (1 to 7) storey the dimension of column will be 750 x 750 mm and after seven to fourteen (8 to 14) for 20 storey building the size of column will be **600 x 600 mm** while for 15 to 20 storey the dimension of column will be 450 x 450 mm.

**Do civil engineers use CAD? ›**

**Civil engineers use CAD to create base maps**. It supports the creation of better construction documentation. Computer-aided drafting, or CAD, was seen as a pleasure rather than a need in the civil engineering sector. Today, though, you won't find a civil engineer who doesn't have CAD knowledge or training.

**What tools do structure designers use? ›**

The primary tool used in structured design is the **structure chart**.

**What are the 3 types of support conditions in beams? ›**

**Roller, pinned, and fixed connections** are the three most common types of supports in beams and structures to connect them to its foundation. Any of these supports can be seen at any point in the length of a structural element. They can be found at the ends, in the middle, or at some other point in between.

**What are 3 types of beams? ›**

**Types of beam structure**

- Continuous beams. A continuous beam is one that has two or more supports that reinforce the beam. ...
- Simply supported beams. Simply supported beams are those that have supports at both end of the beam. ...
- Fixed beams. ...
- Overhanging beams. ...
- Cantilever beam.

**How many loads does a beam have? ›**

How do you calculate beam load? Factors contributing to the total load of the beam are the Weight of Concrete and the Weight of Steel (2%) in Concrete. Hence the **Total Weight of the beam = Weight of Concrete + Weight of Steel**. The Approximate load of a beam of size 230mm x 450mm is around 3.5 KN/m.

**What does a 30 lb roof load mean? ›**

The trick is determining the weight per square foot of whatever combination of snow, ice, slush and water has piled onto your roof. If it's more than 30 pounds, **the roof could collapse**.

**How do you calculate roof load width? ›**

**Roof load width (RLW) = rafter span (if placed at midspan) otherwise ½ span1 + ½ span2**.

**What is 20lb roof load? ›**

This downward imposed load on the home is also known as the snow load. The North Zone design live load equates to 40 pounds per square foot, the Middle Zone equates to 30 pounds per square foot, and **the South Zone** equates to 20 pounds per square foot.

**How far can a triple 2x12 beam span? ›**

How far can a triple 2×12 beam span:- as per general rules and guidelines, #2 grade southern pine of a triple 2×12 deck beam can span upto **15 feet** when total load of 50 psf (40 psf live load + 10 psf dead load) with deflection limit L/360.

### How far can a 4X10 beam span without support? ›

Joist Spans | ||
---|---|---|

Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir, Redwood, Cedars, Ponderosa Pine, Red Pine | 4X8 | 4'-11" |

4X10 | 5'-10" | |

4X12 | 6'-9" | |

3-2X6 | 4'-6" |

**How long can a beam span without support? ›**

Some manufacturers limit their beams to 60' due to transportation issues, while others have the capability to manufacture beams up to 80' long. So, the longest unsupported span possible using LVL would be 80-feet. What is this? Typically, though, it is common for a continuous LVL span to be **between 20' and 30'**.

**How far can a 4 ply 2x12 beam span? ›**

A 4 ply 2×12 or 4-2×12 size wood beam can allow to span **15 feet and 10 inches**, a 4 ply 2×8 or 4-2×8 size wood beam can span 11 feet and 2 inches and a 4 ply 2×10 or 4-2×10 size wood beam can allow to span 13 feet and 8 inches.

**What size LVL beam do I need for a 28 foot span? ›**

What size lvl beam for a 28 foot span:- as per general thumb rule, for a 28 foot span, size of LVL beam or GLULAM should be **15-16 inches deep and 4 inches wide**, thus you need something like a 15-16″ GLULAM or LVL to span upto 28 feet used for residential building or projects.

**How much does a 20 foot LVL beam cost? ›**

The LVL beam thickness is usually between 1.75 and 7 inches. The price for beams that fit 10 feet of space will range from $3 to $5 per linear foot, while a 20-feet span will need a beam that costs **$6 to $11 per linear foot**.

**How far can a 2x12 header span? ›**

As per general rules and guidelines, nominal size of a double 2×12 header can span upto **12 feet**. Thus, 12 feet is maximum allowable span for a double 2×12 size header.

**How do you calculate column load? ›**

Volume of Concrete = 0.23 x 0.60 x 3 =0.414m³ Weight of Concrete = 0.414 x 2400 = 993.6 kg. Weight of Steel (1%) in Concrete = 0.414x 0.01 x 8000 = 33 kg.

**How do you calculate snow load on a roof? ›**

The University of Wisconsin Cooperative Extension Service says that a ballpark estimate of roof snow load can be made with the following formula: **Calculated Roof Loading (lb/ft2) = Depth (ft) x Density (lb/ft2 /ft depth)**. The approximate density (lb/ft2 /ft depth) is: 5-20 for light snow.

**How do you calculate slab load? ›**

**Types of load Calculation on Column, Beam, Wall, and Slab**

- Column's self-weight × Numbers of floors.
- Beam's self-weight per running meter.
- Wall load per running meter.
- The total load on slab = Dead Load( due to storing furniture and other things) + Live load ( due to human movement)+ Self Weight.

**How far can a 2x10 header span without support? ›**

How Far Can a 2×10 Beam or Header Span? A 2×10 beam – made up of two 2x10s nailed together – can span up to **11'** without support beneath a deck that is 4' wide. For a more normal-sized deck, the same beam can span 8', supporting a deck that is 8' wide.

### What size header do I need for a 20-foot span? ›

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.

**How far can a double 2x12 beam span without support? ›**

When supporting joists that span 12 feet with no overhang beyond the beam, a double ply beam can span in feet a value equal to its depth in inches. A double 2×12 beam can span **12 feet**; a (2) 2×10 can span 10 feet and so on.

**How do you calculate loads in slabs and beams? ›**

The slab is commonly divided into trapezoidal and triangular areas by drawing lines from each corner of the rectangle at 45 degrees. The beam's distributed load is computed by **multiplying the segment area (trapezoidal or triangular area) by the slab's unit load divided by the beam length**.

**How do you transfer loads from beams to columns? ›**

Steps on how to load a column from beam support reaction

(1) **Load the floor slab adequately, and factor the loads at ultimate limit state, using the appropriate load combination.** (2) Load all the beams that are connected to the column. (3) Transfer the loads from slab to the beam using the appropriate relationship.

**How do you calculate the weight of a beam? ›**

How to calculate self weight of beam | Dead Load of Beam - YouTube

**What does 20 pound roof load mean? ›**

Estimate how much weight your roof can support

**House roofs should support 20 lbs./square foot of snow before they become stressed**. Local building codes dictate the snow load required for residential roofs.

**How much does a roof weight per square foot? ›**

**Asphalt Shingle: 2 – 3.5 pounds per square foot**. Textured Asphalt Shingle: 3.5 – 5 pounds per square foot. Wood Shingles/Shakes: 3.5 – 4.5 pounds per square foot. Clay or Concrete Tile: 5.5 – 10 pounds per square foot.

**What is typical roof dead load? ›**

Dead Loads

Your roof then needs to be built to support itself. Normally, the dead load of a typical asphalt shingle roofing system with wood frames is **15 pounds per square foot**. A clay-tiled roof, on the other hand, has a dead load of 27 pounds per square foot.

**What are the different types of loads acting on a beam? ›**

four different types of loadings namely, **concentrated load, uniformly distributed load (UDL), triangular load and hat type load** are considered.

**How do you calculate beam and column size? ›**

2) Calculating column size for 5m span for 2 storey/two floor/G+1 residential building, we have given number of floor=2, total number of column = 16, span area=15m×15m, fy=500N/mm2, fck=20N/mm2, thumb rule load=20kN/m2, gross area Ag =100%, steel area Asc =1%ofAg =0.01Ag and concrete area Ac =99%of Ag =0.99Ag.

### Is code for load calculation? ›

...

TABLE 1.12. Minimum Live Loads to be Considered.