The Anatomy of a Deck

Learn All The Technical Terms to Truly Understand Your Deck

The term anatomy may conjure up some creepy images of human dissections, medical books, or Friday the 13th horror movies. Don’t fret, your innards are intact! We’re just going to discuss the anatomy of your deck.  

As with human body anatomy, most things in life have some sort of framework, or an anatomical structure, that can be used to help us comprehend the basics. If you have a deck on your property, or are planning to build one, understanding deck anatomy is critical to helping you make informed decisions. 

Table of Contents

1. The Top
2. The Railing
3. The Frame & Support
4. The Ledger
5. The Posts & Beams

The Top

Let’s start from the top of a deck and move our way down. The most obvious part of a deck is the decking - the boards that you walk on on the deck surface and stairs. The decking is typically made of a hardwood or composite material. Deck boards are typically spaced about 1/8th of an inch apart for maximum drainage and airflow. 

The Railing

The second most visible part of a deck is the railing. Railings are considered life support systems and serve as the outermost edge of the deck, protecting and deck occupants from falling off of exposed edges. 

The rail itself is composed of a few different elements - the balusters, cables, or other post system, the cap rail, and the railing posts. This joint system is used to construct a railing designed to support weight while serving as an aesthetic enhancement feature. 

The Frame & Support

Underneath the decking and railing is the framing itself, the structural wood members that hold the deck together, and keep it safe for you and your family. Running underneath the deck are the joists. Joists are structural grade wood pieces typically measuring 2” by 6” that hold up the deck. 

The joists are typically 10” apart and are separated by bridging, or blocking, that adds support. Along the perimeter of the deck you will find the rim joist, which receives all the joists on the opposite side of the ledger. 

The Ledger

Attached to the house you will find the ledger board. The ledger board is the piece of wood that anchors to the house and catches all of the joists. This board is considered one of the most critical structural members and requires flashing on both the top and bottom. The ledger board is bolted into the floor framing system to anchor your deck.

The Posts & Beams

Holding up the joist system, in a “post and beam deck” you will find just that – a post and beam system serving as support for the entire deck structure. Opposite of the home you will find a beam, or a large structural-grade piece of lumber, running parallel to the ledger underneath the joist system. 

This beam is engineered to support the weight of the deck and deck occupants. Supporting the beam you will find posts spanning the length of the beam to hold it in place. The posts are anchored to the ground using concrete footings, engineered to hold firm in the soil.

With adequate hardware and properly sized framing members, your deck could be engineered to last a lifetime. Here at Rogall + Co., we have an expert team of deck builders. We build from scratch, repair your existing deck, or are able to give your deck a quick facelift with some type of coating.