Loading

How to Splice a Deck Beam Over a Support Post

It is always best to use a continuous beam without seams for higher strength. Dimensional lumber is readily available in lengths up to 20’ which should accommodate a seamless beam for most applications. However, if your span is greater than 20’ (like the image below) you will likely need to splice some boards to form a beam. In order to do this you should overlap the individual parts of the beam so they are staggered if possible. It is best to have one continuous board over a post allowing one joint to fall on top of the post. Overlapping seams integrates strength and prevents fracturing along seams throughout the length of the beam. Always split a beam over a post.

Plan ahead and layout the beam on the ground over the footings before installation. For instance you could use 2-2x10x10’s and 2-2x10x20’s to form a 30’ beam with one seam set above two intermediate posts.  You can also use hardware applications like strap ties or nailing plates to further secure the connection. Because these connectors are not particularly attractive you will probably want to conceal them behind fascia or on the interior side of the beam.

In this case we had to splice 2 sections of beam over a center post with a seam. 

 

Screw the first piece of the beam to the notched post.
PinterestSave
Screw the first piece of the beam to the notched post.

When attaching the first half of the beam to the notched 6x6 support post screw through the center of the 2x10.  This will hold the 2x10 in place until you install the second 2x10 piece of the beam.

Use a 1/2
PinterestSave
Use a 1/2

Drill 2 thru holes on the edges of each beam section through the beam and notched 6x6 post.  Align your holes 2" from the top and bottom and edge of the beam.

Take out your socket ratchet.
PinterestSave
Take out your socket ratchet.

Use a socket ratchet to tighten the 1/2" x 6" thrubolts from one side of each beam section through the beam and notched post.  Use washers to protect the beam from overtightening.  You may also use 8" long thrubolts.

A solid connection.
PinterestSave
A solid connection.

This is a finished view of the beam splice over a support post.  Notice how both sections of the beam are level.


Popular Framing Articles
Deck Support Columns

How to Decorate Deck Support Columns

Browse some examples of decorative deck support posts for tall decks.

Deck Framing

Deck building tools

As with any professional job, having the right tools can make all the difference.

Deck Framing

Roof Top Deck Construction

Rooftop decks transform otherwise wasted space into beautiful planes for entertaining, dining, relaxing and even gardening. The views will make your deck the talk of the neighborhood and draw frequent guests to your home or business.

Next Step: Decking Articles
Decking Installation

Decking Patterns

Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.

Decking Installation

Best Time to Build a Deck

People often wonder when the best time to build a deck is. Learn why building a deck in winter or fall might be your best bet.

Decking Installation

Introduction to Decking

Spacing between deck boards provides several critical functions, such as drainage & drying. Learn how to space and stagger deck boards at Decks.com.

Get more helpful resources delivered right to your inbox

Explore Articles by Topic

Deck Support Beams

How to Splice a Deck Beam Over a Support Post

It is always best to use a continuous beam without seams for higher strength. Dimensional lumber is readily available in lengths up to 20’ which should accommodate a seamless beam for most applications. However, if your span is greater than 20’ (like the image below) you will likely need to splice some boards to form a beam. In order to do this you should overlap the individual parts of the beam so they are staggered if possible. It is best to have one continuous board over a post allowing one joint to fall on top of the post. Overlapping seams integrates strength and prevents fracturing along seams throughout the length of the beam. Always split a beam over a post.

Plan ahead and layout the beam on the ground over the footings before installation. For instance you could use 2-2x10x10’s and 2-2x10x20’s to form a 30’ beam with one seam set above two intermediate posts.  You can also use hardware applications like strap ties or nailing plates to further secure the connection. Because these connectors are not particularly attractive you will probably want to conceal them behind fascia or on the interior side of the beam.

In this case we had to splice 2 sections of beam over a center post with a seam. 

 

Screw the first piece of the beam to the notched post.
PinterestSave
Screw the first piece of the beam to the notched post.

When attaching the first half of the beam to the notched 6x6 support post screw through the center of the 2x10.  This will hold the 2x10 in place until you install the second 2x10 piece of the beam.

Use a 1/2
PinterestSave
Use a 1/2

Drill 2 thru holes on the edges of each beam section through the beam and notched 6x6 post.  Align your holes 2" from the top and bottom and edge of the beam.

Take out your socket ratchet.
PinterestSave
Take out your socket ratchet.

Use a socket ratchet to tighten the 1/2" x 6" thrubolts from one side of each beam section through the beam and notched post.  Use washers to protect the beam from overtightening.  You may also use 8" long thrubolts.

A solid connection.
PinterestSave
A solid connection.

This is a finished view of the beam splice over a support post.  Notice how both sections of the beam are level.


Popular Framing Articles
Deck Support Columns

How to Decorate Deck Support Columns

Browse some examples of decorative deck support posts for tall decks.

Deck Framing

Building A Deck Over An Air Conditioner

Things to consider when building a deck near an air conditioning unit. You may want to relocate the AC unit if possible to avoid some problems.

Deck Framing

Deck Floor Joists

Step-by-step instructions and tips on how to frame. Learn how to install treated wood joists and beams to build a strong deck.

Next Step: Decking Articles
Decking Installation

Decking Patterns

Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.

Decking Installation

10 Common Deck Building Mistakes & How to Avoid Them

Building a deck can be a complicated process. Learn how to avoid falling into common deck building pitfalls with tips and advice from the experts at Decks.com.

Decking Installation

Dos & Don'ts for Homeowners to Consider When Building a Deck

Your dream deck can take whatever shape you like. The trick is making it fit your budget and site conditions. While the deck doesn’t have to be built as a rectangle, there could be good reasons for doing just that.

Get more helpful resources delivered right to your inbox

Explore Articles by Topic