"Do You Need Blocking Between Deck Joists? Expert Answers"

Building a deck is a rewarding project that can enhance your outdoor living space. However, it's crucial to understand the structural aspects to ensure your dec...

Do I Need Blocking Between Deck Joists? A Comprehensive Guide

Deck Joist's Protection from Rotting
Deck Joist's Protection from Rotting

Building a deck is a rewarding project that can enhance your outdoor living space. However, it's crucial to understand the structural aspects to ensure your deck is safe and durable. One common question homeowners ask is, "Do I need blocking between deck joists?" This article will delve into this question, providing a clear understanding of the role of blocking and when it's necessary.

Adding Blocking Between Deck Joists
Adding Blocking Between Deck Joists

Understanding Deck Joists and Blocking

Deck joists are horizontal framing members that support the decking boards and transfer the weight of the deck and its users to the load-bearing beams and posts. Blocking, on the other hand, are small pieces of lumber installed between the joists to provide additional support and stiffness to the deck structure.

a wooden table sitting on top of a cement floor next to a building with the words why blocking?
a wooden table sitting on top of a cement floor next to a building with the words why blocking?

Why Use Blocking Between Deck Joists?

  • Strength and Stability: Blocking helps prevent joists from twisting or racking, which can lead to structural issues over time.
  • Support for Decking Boards: It provides an additional surface for decking boards to rest on, helping to distribute weight evenly and prevent sagging.
  • Improved Safety: By enhancing the deck's stability, blocking can help prevent accidents caused by a wobbly or uneven deck surface.
Sistering Deck Joists
Sistering Deck Joists

When is Blocking Between Deck Joists Necessary?

Building codes and best practices dictate when blocking is necessary. Here are some scenarios where you should install blocking between your deck joists:

Spanning More Than 6 Feet

How far apart should deck joists be spaced?
How far apart should deck joists be spaced?

If your deck joists are spaced 16 or 24 inches on center and span more than 6 feet, blocking is typically required. This is to prevent the joists from twisting or sagging under weight.

Using 2x4 Joists

If you're using 2x4 joists, blocking is usually required to provide additional support and prevent the joists from twisting. This is especially important if the joists are spaced 24 inches on center.

Deck Joist Need Ground Clearance
Deck Joist Need Ground Clearance

Installing Railings or Benches

If you're installing railings, benches, or other heavy structures on your deck, blocking can help provide the additional support needed to prevent sagging or twisting.

Deck Joist Blocking? What is it? Why do we need it?
Deck Joist Blocking? What is it? Why do we need it?
How to sister deck joists
How to sister deck joists
Can You Use 2x6s for Deck Joists
Can You Use 2x6s for Deck Joists
Carpenter’s Reasons For Installing Blocking Between Joists on a Deck - Decks by E3
Carpenter’s Reasons For Installing Blocking Between Joists on a Deck - Decks by E3
45 Ways to Hide the Space Under a Deck
45 Ways to Hide the Space Under a Deck
How to Block Your Deck Joists
How to Block Your Deck Joists
the parts of a bed frame are labeled
the parts of a bed frame are labeled
a man kneeling down next to a dog on top of a pile of dirt and rocks
a man kneeling down next to a dog on top of a pile of dirt and rocks
The Deck: Joists, Blocking & Railing Posts
The Deck: Joists, Blocking & Railing Posts
Deck Blocking and Bridging: The Only Guide You'll Ever Need
Deck Blocking and Bridging: The Only Guide You'll Ever Need
Are Deck Blocks a Good or Bad Idea? Plus Installation - Decks by E3
Are Deck Blocks a Good or Bad Idea? Plus Installation - Decks by E3
How to Frame a Deck: A Guide to Building a Sturdy Foundation
How to Frame a Deck: A Guide to Building a Sturdy Foundation
a wooden bench with the words overhanging decking protecting the rim joist from water
a wooden bench with the words overhanging decking protecting the rim joist from water
How To Install Deck Joists & Blocking
How To Install Deck Joists & Blocking
Deck Replacement vs. Repair: Which Is Right for You?
Deck Replacement vs. Repair: Which Is Right for You?
Deck Block For Joists Used In Conjuncton With Concrete Stirrups
Deck Block For Joists Used In Conjuncton With Concrete Stirrups
Expert Tips for How to Build a Deck
Expert Tips for How to Build a Deck
Common Pitfalls to Avoid When Using Concrete Deck Blocks
Common Pitfalls to Avoid When Using Concrete Deck Blocks
How Many Deck Blocks Do You Need?
How Many Deck Blocks Do You Need?
How to Build a Deck Like a Pro
How to Build a Deck Like a Pro

How to Install Blocking Between Deck Joists

Installing blocking is a straightforward process. Here are the steps:

  1. Measure and cut blocking pieces to fit snugly between the joists.
  2. Position the blocking so that it's flush with the top of the joists. This will provide a flat surface for the decking boards.
  3. Secure the blocking in place using appropriate fasteners, such as screws or nails. Ensure the fasteners are long enough to penetrate at least 1 inch into the joists.

When Can You Skip Blocking?

In some cases, you can skip blocking if your deck joists are spaced 12 inches on center or less and span no more than 6 feet. However, it's always a good idea to consult local building codes and consider the additional benefits of using blocking, such as improved safety and longevity of your deck.

Conclusion

Blocking between deck joists plays a crucial role in ensuring your deck is safe, stable, and durable. While it's not always required, it's a simple and effective way to enhance the structural integrity of your deck. Always consult local building codes and consider the specific needs of your deck when deciding whether to use blocking.

Related Articles