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Install Deck Railing Posts the Right Way

Install Deck Railing Posts the Right Way
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The addition of a deck to your home adds a lot to the enjoyment of your home along with market value. However, it can become a safety hazard and resell liability if its railings are weak or loose. If you install deck-railing posts the right way, you can avoid both of these issues. Here is a step-by-step guide to help you out.



Step One: Preparation

Before installing your deck, consult building codes and obtained the proper permits. Within local building codes, look at specific sections defining various requirements like: 

  • Railing height
  • Spacing between posts
  • Post size or materials
  • Special attachment and reinforcement requirements.


Step Two: Locating Primary Posts

Before you start cutting posts and drilling holes to mount them, determine where you intend to place primary posts and clearly mark their location. Primary posts include: 

  • Wall Posts. To prevent issues with the finish on your home, you will want to allow two to three inches clearance between the post and the wall.
  • Corner Posts. Every inside corner and outside corner of your deck’s layout will require a deck-railing post.
  • Stair Posts. You will need to install stair posts at all four corners of your stairway frame. If your stairway lands in a corner of your deck, then the corner post will serve for a stair post as well.


Step Three: Locating Intermediate Posts

Once you have marked the location of these primary posts, layout the locations of the intermediate posts, or the posts that will be installed between corner and stair posts. Intermediate posts are set between primary posts with spans not exceeding six feet(or other local code dimension) between posts. Do this before cutting and installing so you will have an accurate figure for purchasing the required amount of stock.


Step Four: Cutting Posts

Calculating the right length to cut railing posts includes several elements. The beginning point is the height requirement of your local code, which is commonly 36″, 42″ or a range between the two. Keep in mind that this height includes the cap or rail and the dimension is from the floor of your deck. 

Calculating Post Length

Since you will install railing posts before your deck floor is installed, the railing and deck floor thicknesses cancel each other out. That leaves you with the required height, plus the width of your 2×10 deck frame member. For example, posts for a 36″ height railing will be 36 + 9 ½” = 45 ½”. 

Measure twice and cut once to avoid material waste due to cutting errors.


Step Five: Setting Posts

With your posts cut and ready to install, it is time to start setting your posts, which includes a series of steps: 

  1. Equipment. This includes cut posts, a guide nail, two clamps, level, drill with ½” bit.
  2. Hardware. For each post you install you will need two 6″ x ½” galvanized bolts, 4 flat washers, 2 lock washers and 2 nuts. Some codes also require tension ties on specific posts or all posts.
  3. Post Placement. Place the post with its bottom flush to the bottom of the frame member and draw a line along the top of the frame member on the post.
  4. Guide Nail. Drive a guide nail into the center of the post just above the line you just drew.
  5. Clamp Post. Using the guide nail and the clamps, clamp the post in place using a level to make sure that it plumb before tightening the clamps in place.
  6. Drill Holes. Drill holes about 2″ below the top of the frame and 2″ above the bottom of the frame, which go through the centerline of the post.
  7. Set Bolts. Place flat washers on the bolts and tap each bolt through the holes you just drilled.
  8. Secure Bolts. Place flat washers, lock washers, and then the nuts on the protruding bolts and tighten the nuts until the flat washers are biting into the wood of the frame and the post.
  9. Release Clamps and pull the guide nail.
  10. Move on to the next post.


Step Six: Additional Requirements

Some codes require the addition of tension ties. Follow the proper directions and guidelines for installing tension ties to complete your job before moving onto installing the deck railing and deck floor.


A backyard deck is a great place to enjoy some quality time with family and friends while also adding value to your home. It is more enjoyable if your deck is safe. A major component in deck safety is installing deck-railing posts the right way. Worthington Millwork is a great resource to call upon when it comes to planning and installing your deck. Contact us to find out how we can serve you.