We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is a Crossbeam?

By Lori Kilchermann
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A crossbeam is used in the construction of a building and is designed to support a floor or a ceiling. The crossbeam sits on a ledge of concrete when used over a basement and on a wooden support built into floor or ceiling joists when used in the framing stage of construction. Typically made of laminated wood, reinforced concrete or steel I-beam, a crossbeam is able to support a great deal of weight over a very long span. To aid the crossbeam in its role, steel supports known as floor jacks are placed at intervals under the crossbeam to prevent sagging.

In early construction days, old-growth forests had trees large enough that a crossbeam was often made by creating a single large beam from a single log. Many of the early American barns on farms used crossbeam systems that included beams spanning the width of the barn. Modern beams are created by nailing and gluing multiple boards together to create one thick crossbeam. The reason this is done is that available lumber is unable to produce a single beam from the relatively new forest growth.

When using a laminated lumber beam, it is imperative that the seams or joints from the different lengths of lumber be staggered and not aligned. By staggering the joints, the beam gains strength and will resist bowing or twisting. Often, a piece of plywood is sandwiched between some of the boards to add in the structural integrity of the beam. The plywood, made up of many thin laminates glued together, is often stronger than a piece of finished lumber that has all of its grain running in a single direction.

When using steel for the beam, the most common type of steel is the I-beam. The I-beam allows the beam to have a flat face to sit upon the supports while also having a flat face to build the floor upon. The strength of the I-beam comes from the vertical component of the beam while the flat horizontal elements also provide resistance to bowing or flexing. Often a slight pre-load is placed on the steel beam, causing it to arch slightly when set into position. The process of placing the flooring materials onto the I-beam will cause it to level out under the weight.

Concrete beams reinforced with iron bar and wire mesh are often cast with a slight arch also. This causes the floor to remain level once the weight of the flooring is placed upon it. The crossbeam allows a greater area to be constructed without walls being needed to support it. Thus, larger rooms and open spaces can be designed into a building by an architect.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.