# All About size beam do I need for a 20 foot span

When it comes to building structures, one of the most important factors to consider is the size and type of beam needed to support the intended span. This is especially crucial if you are working with a 20 foot span, as a proper beam size can greatly impact the stability and safety of the structure. In this article, we will delve into the various factors that go into determining the size of beam needed for a 20 foot span, including the type of load, material used, and building codes. Whether you are a DIY enthusiast or a professional builder, understanding the right beam size for your 20 foot span is crucial for a successful and secure construction project.

## What size beam do I need for a 20 foot span?

When constructing a 20 foot span, it is important to determine the appropriate size beam to ensure structural stability and safety. The size of the beam needed will depend on several factors such as the load it will carry, the type of material used, and the structural design of the building.

Here are some key considerations to keep in mind when determining the size beam to use for a 20 foot span:

1. Calculate the Load: The first step is to determine the load that the beam will be required to carry. This includes both the dead load (the weight of the structure itself) and the live load (any additional weight the structure will support, such as furniture or people). The type and amount of load will have a significant impact on the strength and size of the beam needed.

2. Select the Material: The type of material used for the beam will affect the size needed. Common materials used for structural beams include wood, steel, and reinforced concrete. Each material has its own specific properties and strength capacities, so the appropriate size of the beam will depend on the material being used.

3. Consider the Span-to-Depth Ratio: The span-to-depth ratio is an important factor in determining the size of the beam. This ratio refers to the distance between the supports (in this case, 20 feet) and the maximum depth of the beam. In general, the deeper the beam is, the stronger and more stable it will be.

4. Refer to Structural Design Calculations: Civil engineers use various structural design calculations to determine the size of beams needed for specific spans. These calculations take into account factors such as the material used, the load, and the span-to-depth ratio to determine the appropriate beam size.

Based on these considerations, a general rule of thumb for determining the size of a beam for a 20 foot span would be a minimum depth of 10 inches (for wood beams) or 12 inches (for steel or reinforced concrete beams). However, it is important to consult with a structural engineer to accurately determine the size of the beam and ensure it meets all safety and building code requirements.

In conclusion, the size of the beam needed for a 20 foot span will depend on the load, material, and structural design calculations. It is essential to consult with a qualified engineer to determine the appropriate beam size to ensure structural stability and safety.

## Steel beam size for a 20 foot span

When designing a structural steel beam for a 20-foot span, there are several factors that need to be considered. These include the load requirements, support conditions, and the type of steel to be used. In this article, we will discuss the most common steel beam sizes for a 20-foot span and their corresponding weight and section properties.

1. W10x33 Beam
The W10x33 beam is a popular choice for 20-foot span bridges and buildings. It has a depth of 10 inches and weighs 33 pounds per linear foot. This beam is commonly used for medium to heavy loads and can span up to 25 feet. The moment of inertia for this steel beam is 642 in^4 and the section modulus is 48.2 in^3, making it a strong and viable option for this span length.

2. W8x18 Beam
The W8x18 beam is a lighter option for a 20-foot span, with a depth of 8 inches and a weight of 18 pounds per linear foot. This beam is commonly used for light to medium loads and can span up to 21 feet. The moment of inertia for this beam is 145.4 in^4 and the section modulus is 20.5 in^3, making it suitable for smaller structures or where weight is a critical factor.

3. W12x26 Beam
The W12x26 beam is a heavier option for a 20-foot span, with a depth of 12 inches and a weight of 26 pounds per linear foot. This beam is commonly used for heavier loads and can span up to 30 feet. The moment of inertia for this beam is 850 in^4 and the section modulus is 57.1 in^3, making it a strong choice for structures that require more support.

4. W14x38 Beam
The W14x38 beam is the heaviest option for a 20-foot span, with a depth of 14 inches and a weight of 38 pounds per linear foot. This beam is commonly used for the heaviest of loads and can span up to 36 feet. The moment of inertia for this beam is 1550 in^4 and the section modulus is 79.2 in^3, making it the strongest and most rigid option for this span length.

It is important to note that these beam sizes are just a few examples of commonly used options for a 20-foot span. The appropriate size for a specific project will depend on the specific design and load requirements. It is always recommended to consult with a structural engineer to determine the most suitable steel beam size for a particular project.

In conclusion, the selection of a steel beam size for a 20-foot span should be done carefully, considering the load requirements, support conditions, and type of steel to be used. With the right design, a properly sized steel beam can provide strong and reliable support for various structures.

## Wood beam size for a 20 foot span

Wood beams are commonly used in construction for their strength, durability and cost-effectiveness. When designing a structure, it is important to carefully consider the size of the wood beams, as they are crucial in supporting the weight of the load above and ensuring the overall stability of the structure.

For a 20 foot span, there are a few factors that need to be taken into account when determining the appropriate size of a wood beam. These include the type of wood, the spacing of the beams, the type of load the beam will support, and the building code requirements.

The type of wood used for the beam is a crucial factor in determining its size. The most commonly used types of wood beams are treated Southern Yellow Pine, Douglas Fir, and Western Red Cedar. These types of wood have different strengths and bending capacities, which determine the size of the beam required for a 20 foot span.

The spacing of the beams also plays a significant role in determining the size. If the beams are spaced further apart, a larger beam will be needed to support the load, whereas a smaller beam can be used if the spacing is closer together.

The type of load that the beam will support is another important consideration. If the beam will be supporting heavy point loads, such as from a roof system or a girder, a larger beam will be required. On the other hand, if the beam is only supporting a light load, a smaller beam may be sufficient.

In addition, building codes play a vital role in determining the size of the wood beam. These codes have specific requirements for the maximum deflection (bending) and stress limits that the beams can withstand. The size of the beam must meet these requirements to ensure the safety and stability of the structure.

Based on these factors, a common size for a 20 foot span wood beam would be a 6×12 or 8×10. However, the exact size may vary depending on the factors mentioned above and the calculations done by the structural engineer or architect for the specific project.

In conclusion, the size of a wood beam for a 20 foot span will depend on the type of wood, beam spacing, type of load, and building code requirements. It is essential to carefully consider all these factors to ensure that the structure is safe, stable, and meets the necessary building standards.

## What size beam to span 20 ft

There are several factors to consider when determining the appropriate size beam to span a distance of 20 feet. These include the type of load the beam will support, the type of material it is made of, and the spacing between the supporting posts or columns.

The first step in selecting the right beam size is to determine the load that it will need to bear. This can vary greatly depending on the intended use of the structure. For example, a residential home will likely have a lower load requirement compared to a commercial building.

Next, the type of material the beam is made of will also play a role in its size. Common materials used for beams include wood, steel, and reinforced concrete. Different materials have different load-bearing capacities, so it is important to consult with a structural engineer or refer to building codes to determine the appropriate size for the selected material.

The spacing between the supporting posts or columns is also a crucial factor. The larger the spacing, the more load the beam will need to bear, requiring a larger size beam. The type and size of the supports themselves can also affect the beam size. For example, a beam spanning 20 feet with support on both ends will require a smaller size compared to a beam with one end supported and the other cantilevered.

In general, for a residential structure with evenly distributed loads, a wood beam size of 8”x17” or 10”x20” is suitable for a 20-foot span. For a commercial building, steel or reinforced concrete beams may be needed for larger load-bearing capacity.

It is important to note that accurate calculations are necessary to determine the precise beam size for a specific project. Consulting with a structural engineer is recommended to ensure the safety and stability of the structure.

In summary, when choosing the size beam to span 20 feet, factors such as load, material, and support spacing must be taken into consideration. The size of the beam should be carefully selected to ensure proper structural support and safety for the intended use.

## LVL beam size for a 20 foot span

A Laminated Veneer Lumber (LVL) beam is a structural element commonly used in construction for its strength and versatility. It is made by bonding together multiple thin layers of wood veneers with adhesives to form a strong and durable beam. LVL beams are often used in place of traditional solid wood beams due to their superior strength to weight ratio and ability to span longer distances.

When determining the appropriate LVL beam size for a 20-foot span, several factors must be taken into consideration. The most important factor is the load that the beam will need to support. This includes the weight of the structure above the beam, such as flooring, walls, and roof, as well as any additional loads from furniture, people, and snow or wind in the area.

The width and spacing of the supports for the beam, such as walls or columns, also play a crucial role in determining the appropriate LVL beam size. The closer the supports are to each other, the shorter the span the beam can support, and the smaller the required beam size will be. However, if the supports are further apart, the beam will need to be larger to distribute the load effectively.

The type of wood used for the LVL beam also affects its size. Different species of wood have varying strength properties, and some may be better suited for longer spans than others. Pine, for example, is a commonly used species due to its affordability and high strength, making it a suitable choice for LVL beams.

In general, for a 20-foot span, a 3-ply 2×12 inch thick LVL beam would be suitable for most residential applications. This means that three 2×12 inch LVL beams would be bonded together to form one solid beam. However, if the load requirements are higher, a thicker 4-ply or even 5-ply beam may be necessary.

It is essential to consult with a structural engineer or local building code requirements to determine the exact LVL beam size needed for a 20-foot span in a specific construction project. They will be able to consider all the necessary factors and provide the appropriate beam size to ensure a safe and efficient structure. It is also important to ensure that the LVL beam is installed correctly, following the manufacturer’s instructions and local building codes, to maintain its structural integrity.

## Conclusion

In conclusion, the size of the beam needed for a 20-foot span depends on several factors, such as the weight it needs to support, the type of material used, and the spacing between the beams. It is important to consult with a structural engineer or a knowledgeable contractor to determine the appropriate size beam for your specific project. By considering all of these factors, you can ensure the safety and stability of your structure. Remember to always prioritize safety over cost when it comes to selecting the right beam size. With proper planning and consultation, you can confidently build a durable and reliable structure for your 20-foot span.