What Size Beam Do You Need For a 30 Foot Span?

When it comes to beams, one of the most important considerations is the span. That’s why, when choosing a beam for a 30 foot span, it’s important to select one that is of the appropriate size. But what size beam do you need for a 30 foot span?

Here, we’ll provide some guidelines to help you select the right beam for your project.

Checkout this video:


When it comes to having a strong and sturdy beam, the most important factor is choosing the right size beam for your span. Whether you’re building a new home or adding an addition to an existing one, you need to make sure the beam can handle the weight and stress it will be under.

There are a few things to consider when choosing a beam for your project. The first is the span of your project. The longer the span, the stronger the beam needs to be. The next is the weight that will be placed on the beam. This includes the dead load, which is the weight of the materials that make up the beam itself, and the live load, which is anything that will be placed on top of the beam once it’s completed, such as furniture, appliances, or people.

Once you’ve considered these factors, you can use our beam calculator to determine what size beam you need for your span and load. Simply enter in your desired span and load and our calculator will do the rest.

If you’re still not sure what size beam you need or have any other questions about beams, please don’t hesitate to contact us. We’re always happy to help!

The Three Main Types of Beams

Beams come in all shapes and sizes, but there are three main types that are used most often. The first type of beam is the cantilever beam. This beam is supported at one end and unsupported at the other. The second type of beam is the simply supported beam. This beam is supported at both ends. The third type of beam is the fixed beam. This beam is supported at both ends and also has rigid connections between the supports.

W-Shaped Beam

The three main types of beams are the I-beam, the H-beam, and the W-beam. Each of these beams has a different shape and is used for different purposes. I-beams are the most common type of beam. They are usually made of steel or concrete and are used in construction. H-beams are another type of beam that is commonly used in construction. They are made of two pieces of metal that are joined together at the middle. W-beams are the third type of beam. They are made of three pieces of metal that are joined together at the middle.

S-Shaped Beam

The three main types of beams are S-shaped, I-shaped, and C-shaped. S-shaped beams are the strongest type of beam. I-shaped beams are the second strongest type of beam. C-shaped beams are the weakest type of beam.

C-Shaped Beam

A C-shaped beam is a type of beam that is shaped like the letter “C”. This type of beam is often used in construction and engineering projects. C-shaped beams can be made from a variety of materials, including wood, steel, and concrete.

How to Determine the Right Size Beam

To support a 30-foot span, you need a beam that can bear the weight of the decking and anyone who will stand on it. The size of the beam you need depends on the lumber you use. For example, if you use 4-by-8-inch lumber, you need a beam made from two 2-by-8-inch boards laminated together.

Use a Beam Span Chart

One of the most important factors in choosing the right beam for your project is the span of the beam. The span is the distance between the two points that the beam will be supporting. Beams are available in a variety of sizes, but not all sizes will be suitable for every span. To determine what size beam you need, you can use a beam span chart.

Beam span charts are available for different types of beams, including wood beams, steel beams, and concrete beams. Each type of beam has its own chart because the strength of each type of beam varies. To use a beam span chart, simply find the beam type that you are using and look at the chart to find the appropriate size beam for your project.

Use the Load Capacity

Beams come in all sorts of sizes and choosing the right one for your project can seem daunting, but it doesn’t have to be. The best place to start is by determine what the beam will be used for and how much weight it needs to support. Once you know that, you can begin to narrow down your choices.

There are a few different ways to find out the load capacity of a beam. The first is by looking in a span chart. These charts can be found in many places online and in construction manuals. They list common beam sizes and their corresponding span and load capacities.

Another way to find out the load capacity of a beam is to use calculus. This method is more accurate but also more complicated. To use calculus, you will need to know the dimensions of the beam, the type of wood, and the weight it needs to support. With that information, you can calculate the moment of inertia and the section modulus of the beam. These two values will tell you everything you need to know about the strength of the beam.

Once you have determined the load capacity of the beam, you can begin to look for one that will fit your needs. Be sure to check with your local building code office before purchasing a beam to make sure that it meets all the requirements for your project.

Use the Deflection

The size of the beam you’ll need is determine by the span of the project and the load or weight the beam will be carrying. To calculate the maximum load the beam can carry, use the formula:

Maximum Load in Pounds / Deflection in Inches = Beam Size in Inches

To use this formula, you must first know what your project’s maximum load will be in pounds and how much deflection is allowed. Once you have those two numbers, solving for beam size is a simple division problem.

For example, let’s say you are using a beam to support a roof on a 30-foot span and you’re allowed 1/360th of an inch of deflection. To calculate how big your beam should be, divide 30 by 360 to get .0833 feet. This is less than an inch, so you’ll need a 1-inch beam.


Beams of this size are uncommonly used in home construction, so you may have difficulty finding one at a local lumberyard or home center. You may be able to find a beam of this size at a salvage yard or through a lumber company that specializes in reclaimed lumber. If you’re unable to find a beam of this size, you can use two smaller beams to support the span.