Building a deck is exciting. You might picture family cookouts, quiet coffee in the evening, or kids running around outside. But before you enjoy those moments, the deck has to be safe and strong. A big part of that safety comes from deck beams. These beams support the weight of the deck and keep it steady. Many homeowners wonder when beams are needed and what options are best.
Let’s walk through the answer together. I will explain what beams are, why most decks need them, the few times you might not, and the options you have. By the end, you’ll know exactly why beams matter and how they keep your deck safe for years.
What Is a Deck Beam and Why Does It Matter?
Think of a deck like a team. The boards on top are the players. The beams are the coaches who keep everything working together. A deck beam is a long, horizontal piece of wood. Sometimes it can also be made of steel. The beam supports the smaller boards called joists. The joists then carry the decking boards where you walk.
The beam also moves the weight down to the posts and into the ground. Without beams, a deck would be like a table without legs. It would be shaky and unsafe. Beams spread out the weight so the deck does not bend or fall.
Why Most Decks Need Beams
Strong Support
Beams carry the weight of your deck. Every step, chair, or grill adds pressure. Beams spread that weight so the deck feels steady under your feet.
Bigger Decks Need Extra Help
Small decks can sometimes work without beams. But if your deck goes far from the house, joists alone cannot hold it. Beams bridge the gap and stop the boards from bending.
Building Codes Require Them
Most cities, including here in Virginia, follow strict rules for decks. These rules almost always require beams. Inspectors check to make sure beams and posts are in the right place.
More Design Choices
Beams give you more options. You can build a second-level deck, add a roof, or keep storage space under the deck. Beams make these designs possible.
Longer Life for Your Deck
A deck with strong beams lasts longer. Without them, joists can sag or crack over time. Beams protect the structure and reduce costly repairs.
Peace of Mind
When you know your deck is built on solid beams, you can relax. You won’t worry about the deck shifting or failing when friends and family gather on it.
Can You Build a Deck Without Beams?
In rare cases, yes. If your deck is very small and close to the ground, you may not need beams. For example, a little platform for a grill or a landing by your back door might only use joists and footings. But for almost every other deck, beams are necessary. Skipping them can lead to sagging, cracking, or even collapse. It’s not worth the risk.
Types of Deck Beams
Not every deck uses the same kind of beam. The right one depends on how big your deck is and how you want it to look.
Drop Beams
A drop beam sits under the joists. This is the style most people use. It is simple, strong, and easier to put in. You can see the beam from below, but it gives solid support and works well for almost any deck.
Flush Beams
A flush beam sits even with the joists. This makes the bottom of the deck look flat and neat. It’s a good choice if you want to keep storage space under the deck or just want a clean look. It takes more work to build, but it makes the deck look nicer.
Steel or Glulam Beams
Some decks are so big or heavy that wood alone is not enough. In those cases, builders use steel beams or special wood called glulam. These beams are very strong and can stretch across wide spaces without needing lots of posts. They cost more, but they make the deck last longer and feel more open underneath. Every type has its place. Drop beams are the easiest and most common. Flush beams give a tidy look. Steel and glulam beams are best for big, heavy decks
Beam Sizes and Spans
How big a beam should be depends on a few things. First, the type of wood. Some woods are stronger than others. Second, the distance between the posts. The farther apart the posts, the bigger the beam needs to be. Third, the weight the deck must hold. A deck with heavy furniture or lots of people needs stronger beams.
As a general rule, posts are usually 6 to 8 feet apart. Builders use official tables from the International Residential Code, or IRC, to pick the right beam size. That is why professional deck builders, like us at LHC Services, always follow the code before choosing materials.
Conclusion
Beams are the backbone of most decks. They keep the structure safe, steady, and long-lasting. While tiny decks can sometimes go without them, almost every standard deck needs beams for strength and code approval. At LHC Services, we’ve built decks all across Richmond and know exactly how to size, place, and secure beams for your home. If you’re planning a new deck or worried about an old one we will be glad to help.
Frequently Asked Questions
Don’t make beams too small for the deck’s size. Always use strong, corrosion-resistant hardware. Keep the beams dry and well-drained to prevent rot. Make sure posts are in the right place and follow building codes. Avoid skipping steps or guessing measurements.
If the beam spans too far, it will bend or sag. Add posts to shorten the span and keep the deck steady. A good rule is to check span tables or codes for your beam size and deck weight.
Look for sagging, soft spots, cracks, or discoloration. Tap the wood with a hammer—soft or hollow spots can mean rot. If the beam is weak, it should be replaced.
Small cracks in wood are normal. Large cracks that weaken the beam need repair. You can fill minor cracks with wood epoxy, but bigger cracks may require replacing the beam. Always make sure the deck stays safe before using it.