What size beam for A 30 foot Span? This is a question very frequently asked by persons looking to build a house.
The diameter of the column depends on the distance between its two pillars, its alignment, and the overall weight(load) applied to it.
So, we will discuss what size beam for a 30 foot span you would need considering all these factors.
What Size Beam For A 30 Foot Span?
A decent rule of thumb is to take your span in feet and divide it by twenty. You have to divide 30 feet (360 inches) by 20.
So, you would get 18 inches. Depending on the beam type, such as UB’s, w beam, universal beam, steel beam, etc., the beam size varies.
Possible beam sizes for 30 foot span:
For a better understanding, here we have calculated the beam sizes of LVL and steel for a 30-foot span.
A steel beam is further divided into three more categories as the beam sizes vary based on the beam type.
| Method Used | Beam | Beam Size |
|---|---|---|
| LVL beam | or GLULAM | 16-18″ |
| Steel | W beam | W18 |
| Steel | UB | UB 450×180 |
| Steel | ISMB | ISMB 450 |
type of beam for a 30-foot span
When considering the appropriate type of beam for a 30-foot span, several options are available.
Here are some of the most common beam types:
Timber Beams:
Timber beams, also known as wood beams, are a popular choice due to their natural look and availability.
They are also a cost-effective option for smaller spans.
Timber beams have limitations in terms of strength and durability, and they may not be suitable for larger or more complex structures.
Steel Beams:
Steel beams are strong, durable, and can span longer distances than timber beams.
They are also fire-resistant and can be easily customized to fit specific project requirements.
Steel beams are typically more expensive than timber beams, and their installation can be more complex due to their weight.
Engineered Wood Beams:
Engineered wood beams, such as laminated veneer lumber (LVL) and glue-laminated timber (glulam), are made by binding wood fibers or veneers together with adhesive.
These beams are strong, durable, and can be customized to fit specific project requirements.
They are also more sustainable than traditional timber beams since they use less wood.
Calculating the size of the beam needed
Calculating the appropriate size of the beam is crucial for ensuring the structural integrity of a 30-foot span.
Here are the steps involved in calculating the size of the beam needed:
Determine the maximum allowable deflection:
The maximum allowable deflection is the amount of bending or sagging that is acceptable for the beam.
This will depend on the type of structure and its intended use.
For example, residential structures typically have a maximum allowable deflection of L/360 (L being the span length) while commercial structures may require a smaller deflection limit.
Calculate the moment of inertia and section modulus:
The moment of inertia and section modulus are measurements of a beam’s strength and stiffness.
These can be calculated using mathematical formulas that take into account the beam’s shape and material properties.
Determine the total load:
The total load includes the dead load (the weight of the structure and any permanent fixtures) and the live load (the weight of people, furniture, and other temporary items).
Use load tables or engineering software:
Load tables or engineering software can help determine the size of the beam needed based on the total load and spacing considerations.
These tools provide information on the allowable stress levels for different types of beams and can help select the most appropriate size.
What Affects The Beam Size?
The span and construction of every structure differ, of course.
This structural difference includes everything from columns, floor joists, decking, and grinders to beams and other structural members.
As a result, it is critical to know what sort of beam you require in the current circumstance before determining the depth or size of the beam.
The beam load:
The load of the beam is the most important consideration here. For this, you will have to consider two types of loads to determine the beam size efficiently.
That’s why most people seek help from professionals. But, here we are to help you out.
Loads might be axial or lateral. The distance between the columns, the number of floors, and whether or not it is short or slim all have a role in the load.
The span trusses:
When span trusses are clear, the outside wall only has to carry half the load that each of the walls has to carry.
For a better understanding, consider you have a structure of 24 X 24 footprint with trusses.
The approximate load on the roof of this structure will be 30 pounds. Consequently, you have next to no storage in the ceiling.
If the structure has a wall in the middle, the load will be minimal. But, without the wall, the external wall will face twice the load we calculated now.
Girders for flooring and beams:
Once again, you should aim for a beam width of anywhere between 1/3 and 1/2 of the span’s total length.
A girder would have the same dimensions. The flange would be thicker, but that’s the only difference.
A beam overhang is an option as well. Overhangs are a great way to add visual interest and structural support to a design.
An overhanging beam cannot exceed 3/8 of the building’s span it supports. Be aware of this while planning an overhang for the support beam.
The easiest approach to figure out how wide a beam should be for any given span is to divide the measurement (inches) by 20.
It will ensure that you get a precise measurement, rather than relying on an educated guess. So, Utilize the aforementioned formula to your advantage.
Flooring joists:
For hardwood flooring, you can also use light-gauge steel joists. In addition to trusses, they can be used interchangeably with these beams.
A 10-foot span may be covered with a 6-inch depth. If you want to span 2 feet more, you will need additional 2 inches of depth. But the maximum spread is 12 inches.
When you cross this 12-inch limit, you will need 3 inches of depth to span 2 additional inches.
Following the formula is essential to assure the floor’s stability by placing supports where they are needed.
Columns:
The amount of floor space a column must sustain dictates the column’s size. In order to calculate the floor area of a column, take the middle column as the standard.
Measure the distance from the standard column to any other nearest column. There is this cumulative effect as you ascend the floors.
For instance, for a 750 square feet space, you would need a 6 X 6 column. To hold 6,000 square feet of weight, you will need a 12 X 12 column.
Floor decking:
There are situations when girders and beams won’t be necessary for your flooring. Joists and decking can be of use then.
So, you’ll need a new technique for gauging the extent of your support.
Metal decking has studs. They can be 2 inches deep and stretch 10. Every inch of depth spans 5 more feet.
Deck depth isn’t the sole consideration. Over the floor, pour 2 to 3 inches of concrete. The proper size ensures stiffness.
Dimensions coordination:
A more effective method to use the dimensions you’re working with is to make sure they’re all in sync.
This will improve the overall efficiency of the project’s construction, which is always the aim.
FAQs About Right Size Beam For A 30 Foot Span
How Do You Span 30 Feet?
You can span 30 feet in one of the many ways possible. Usually, most people prefer the steel beam.
But other beam options such as wooden structures, LVL, and fabricated timber are also used.
Is I-Beam Good For A 30 Foot Span?
Sometimes we use I-beam to refer to the steel beam. So, I-beam or still beam is as good as it ever gets.
If you follow the thumb rule and consider the needed factors, then a steel beam is one of the safest options for homeowners for a 30-foot beam.
What is the equation for 30 foot span?
The beam size equation for any type of span is the same, which is “M = (wL^2)/8”.
In this equation, w represents the total load.
For measuring the steel stress you have to follow another equation, which is @σ = Mc/I.
How Much Is A 30 Foot Beam?
A 30-foot beam may cost from $150 to $550 or even more considering various factors.
For instance, prices for steel I-beams typically range from $180 to $540.
On the other hand, H-beams can cost up to three times as much as I-beams.
But they are three times as strong and three times as long in their spans of support.
Final Words:
For the sake of a building’s overall structural soundness, support beams are an essential component.
That’s why it is essential to determine not only the position of these beams but also their appropriate length and strength.
In short, you must know what size beam for a 30 foot span you need for your building.
