Post and beam construction uses many different strong and durable wood joints. Each type of joint requires a high level of carpentry skills; craftsmen use both tools and techniques to ensure quality work. Post and beam joinery is a skill that can be practiced and learned.
A lap joint is used when a beam or post needs to be extended in length. The joint is formed by removing 2 to 3 inches of thickness from the side of the ends that will connect. Each post or beam is then connected by overlapping the next.
Mortise and Tenon
Mortise and tenon joinery is used when beams tie into posts from the side at a 90-degree angle. This joint is created by chiseling away wood on the beam end on all four sides, leaving a 2- to 4-inch tenon on the end. A mortise, which corresponds to the size of the beam tenon, is then chiseled into the post that will receive the beam tenon. Mortise and tenon joinery is the most popular method of post and beam construction.
Dovetail joints are made by chiseling dovetail shapes in posts and beams. Generally, wood is removed in the shape of a dovetail on the side of a post, creating a pocket. The end of a beam is cut into a mirror-image dovetail shape; the end of the beam then slides into the dovetail notch chiseled into the side of the post. This very strong joint works best to prevent posts and beams from spreading apart.
Tongue and Fork
The tongue and fork joint is used to connect rafters at the ridge. One end of the rafter is carved by removing the center of the wood material about 4 inches from the end, creating a fork. The other end of the rafter connector is carved by removing the outside material of the wood about 4 inches from the end, leaving a tongue, which is then inserted into the fork on the other rafter.
- "The Craft of Modular Post & Beam: Building Log & Timber Homes"; James Mitchell; 1997
- "A Timber Framer's Workshop: Joinery, Design & Construction of Traditional Timber Frames"; Steve Chappell; 1998
- "Timber Frame Construction: All About Post and Beam Building"; Jack Sobon and Roger Schroeder; 1984
Types of Dovetail Joints
Dovetail joints connect framing or panels with wedge-shaped mortise and tenon joinery. In a dovetailed corner, tightly fitting dovetails resist twisting forces...
How to Build a House Post Beam
Post and beam construction is a tried and true method of building houses. In fact, it is one of the oldest home-building...
How Do I Splice Wood Beams?
To get a strong splice on wooden beams, you must use a scarf joint. A scarf joint exposes a large amount of...
How to Notch a Wood Beam
Wood beams used for structural frames or supporting posts are often notched to make strong joints with other beams. Cut notches into...
How to Notch Post & Beam Joints
Post and beam joints consist of half lap joints. Each board is notched to the width of the beam and to a...
How to Build a Round Log Post & Beam
Simply explained, the post and beam design uses two posts and one beam. The posts are logs placed vertically, to support a...
How to Put a Support Beam Under Long Rafters
Often, long rafters need a support beam to help them handle the weight they are required to support on a structure. These...
How to Cut Timber Frame Joints
Timber frame joints are used for many types of timber structures. Barns, cabins, and other types of buildings commonly use timber frame...
Types of Construction Joints
The fundamental nature of construction is joining one piece of wood to another, using one of several joints that are commonly used...
Beam & Post Construction Techniques
Beam and post construction utilizes a framework of horizontal timbers known as beams and vertical timbers known as posts. The framework pieces...