If you are building a deck, front porch, etc. you are likely going to enconter a situation where you need to attach a horizontal beam to a vertical post.
In this article I will show you the best methods for attaching a beam to a post and one method that you should probably never use!
Additionally, I will let you know my personl favorite method and the method I most commonly use for my deck projects.
Method 1: Attaching the Beam to the Top of the Post
The first method for attaching a beam to a post is the “Post Cap” Method. This method involves the installation of post cap harware directly on top of the post. This hardware will hold the beam in place and allow for direct bearing on the post below – which is exactly what you want.
Method 2: Notching the Post around the Beam
The second method for attaching a beam to a post is the “Post Notch” Method. The is my favorite method and it requires you to cut out a notch in the post that will “house” the beam. The notch method allows for direct bearing on the post and the notch serves to brace the beam laterallly.
The “Post Notch” method is typically best suited for larger posts (e.g. 6″x6″ posts) and requires you to cut out the notch using a circular saw / reciprocating saw.
The size of the notch will depend on the size of the beam you are installing. In my case, I used a 2, 2×10 double beam – so I cut the notch around 9.5″ deep by 3″ wide (nominal dimensions of the lumber).
After placeing the beam on top of the post notch and confirming that the posts are perfectly plumb and the beam is level, secure the beam to the post using suitable hardware. In my case, I used two “Thru-Lock” bolts for each beam to post connection.
Note that if there is a beam splice that occurs on top of a post, 4 bolts are typically required. Refer to the image / detail above for additional information.
Method 3 (Don’t Use): Attaching the Beam to the Sides of the Post
The final method is the “Side Mount” and it is one that I NEVER Recommend. Further, this connection method is typically prohibited by code in many jusrisdictions. Sadly, I still see this type of connection all the time…
This connection puts all of the vertical load on the hardware that attaches the beam to the post, making it the weakest type of connection. I only show this method since it is one you might encounter when demolishing an existing deck. Now, you know that it is bad practice.
Conclusion and Final Thoughts
Although the “Post Cap” and “Post Notch” Methods are both great, I recommend the “Post Notch” method since it’s my favorite way to attach a beam to a post. As long as you steer clear of the “Side Mount” Method, you should be all set!
If you are more of a visual learner (or is you are bulding a deck), I recommend that you check out my “How to Frame a Deck Video” which will show you the “Post Notch” method in detail.
Thanks for reading and good luck with your project!
DISCLAIMER: This is a reference guide only. Consult local code requirements. Links included in this article might be affiliate links. If you purchase a product or service with the links that I provide, I may receive a small commission. There is no additional charge to you! Thank you for supporting ATimprovements so I can continue to provide you with free content each week!