--- title: How to Install Horizontal Bar Railing description: "On this page[Introduction](#)[Before You Begin](#)[Prerequisites](#)[What You Need To Know](#)[Tools](#)[Materials](#)[Installation Steps](#)[Step 1. Measure the Run and Lay Out Bar Spacing](#)[Step 2. Set the First Post](#)[Step 3. Fit the Bars to the First Post](#)[Step 4. Set the Next Post, Capturing the Bars,…" url: "https://letsbuildstuff.co/learn/install-horizontal-bar-railing/" updated: "2026-09-27" category: Stairs/Handrails tags: - Level 2 --- # How to Install Horizontal Bar Railing On this page[Introduction](#)[Before You Begin](#)[Prerequisites](#)[What You Need To Know](#)[Tools](#)[Materials](#)[Installation Steps](#)[Step 1. Measure the Run and Lay Out Bar Spacing](#)[Step 2. Set the First Post](#)[Step 3. Fit the Bars to the First Post](#)[Step 4. Set the Next Post, Capturing the Bars, and Repeat](#)[Step 5. Install the Rail](#)[QC / Punch Checklist](#)[Related Guides](#) [Stairs/Handrails](/learn-category/stairs-handrails/) Skill Level: [Intermediate (Level 2)](/learn/difficulty-levels/#level-2) · Estimated Time: 45-60 Minutes Per Section ## Introduction A horizontal bar railing is a [guardrail](/glossary/stairs/#guard-guardrail) built the same way as our standard baluster railing: horizontal bars fill the space between posts instead of vertical balusters. The posts, rail, and rail height do not change. That build is covered in [How to Install Metal Balusters](https://letsbuildstuff.co/learn/metal-balusters/) and is not repeated here. What is different: the bars go in as the posts are set, not after the rail is up, and the work is counted by linear foot of rail, not by bar count. Installing the bars is a task that demands precision and attention to detail, and the 4 inch sphere rule for guard openings comes from [IRC Chapter 3](https://codes.iccsafe.org/content/IRC2021P2/chapter-3-building-planning). The same rule governs bar spacing that governs baluster spacing: no opening between two bars, or between an end bar and a post, may pass a 4 inch sphere. ## Before You Begin ### Prerequisites - Stair or landing framing is complete, and any treads or flooring the posts anchor into are finished. - Bar spacing is worked out for the full run before any post is set, since posts and bars go in together, not in separate passes. - All bars, posts, rail stock, and fasteners are on site and checked against the material list. ### What You Need To Know - The rail is the same rail we build for [metal balusters](https://letsbuildstuff.co/learn/metal-balusters/): 36-1/4 inches from the walking surface to the top. Only the infill changes. - This job is counted by linear foot of rail, not by number of bars, so measure and record the run length. ## Tools - Drill/Driver, for pre-drilling and driving fasteners at the post connections. - [Miter saw](/glossary/tools/#miter-saw-12in-sliding-compound), for cutting bars to length. - Laser Level, to keep bar and post layout marks aligned across the run. - Torpedo level, to check each post and bar for plumb and level as you go. - Tape measure, for the run length and all layout marks. - [Speed Square](/glossary/tools/#speed-square), to check each post square to the framing. - Clamps, for holding a bar in position while the next post is set over it. ## Materials - Horizontal bars, cut to length for the run. - Silicone, for setting the bar ends in the drilled posts - Post and rail material, per [How to Install Metal Balusters](https://letsbuildstuff.co/learn/metal-balusters/). - Fasteners for post-to-framing connections, the same as any [newel post](/learn/install-newel-post/) installation. ## Installation Steps ### Step 1. Measure the Run and Lay Out Bar Spacing Measure the full run end to end and record the length in linear feet: this job is counted by linear foot of rail, not by bar count. Use that length to lay out bar spacing before any post goes in, holding to the 4 inch sphere rule at every post. ### Step 2. Set the First Post Set and plumb the first post the same way as for a baluster rail, secured to the framing and solid before anything fastens to it. Do not set every post first and come back for the bars: they go in as the posts are set, not after the rail is up the way balusters do. ### Step 3. Fit the Bars to the First Post With the first post plumb and secured, fit the bar ends for that section into the post at your layout marks. Drill the post for each bar and set the bar end in silicone. Epoxy is the baluster method, where the joint carries structure; a horizontal bar end gets silicone. Check each bar for level before you move on. ### Step 4. Set the Next Post, Capturing the Bars, and Repeat Position the next post over the free ends of the bars you just fitted, so it captures them as it goes in. Plumb and secure it, confirm the bars are level and on their marks, then repeat down the rest of the run: lay out, fit, capture. A post out of plumb, or bars fitted before the post ahead of it is secured, is much harder to fix once several sections are in. ### Step 5. Install the Rail Once posts and bars are set, build and install the rail per [How to Install Metal Balusters](https://letsbuildstuff.co/learn/metal-balusters/), same rail stock, same post connection, same 36-1/4 inch height to the top of rail. Nothing about the rail changes for this infill. ## QC / Punch Checklist - Run length is measured and recorded in linear feet, not counted by number of bars. - Every post is plumb and solid, with no movement when pushed. - Bar spacing is even across the run; a 4 inch sphere cannot pass between any two bars or between an end bar and a post. - Every bar is level with no play, and the rail is solid at 36-1/4 inches to the top with no flex at the post connections. ## Related Guides - [How to Build a Handrail for Metal Balusters Like a Pro](https://letsbuildstuff.co/learn/metal-balusters/) - [How to Install a Newel Post](https://letsbuildstuff.co/learn/install-newel-post/) - [How to Secure and Finish a Stair Baluster](https://letsbuildstuff.co/learn/secure-baluster-in-stair-railing/) - [How to Install a Wood Wall Cap](https://letsbuildstuff.co/learn/install-wood-wall-cap/) - [How to Install a False Tread Stair End Cap](https://letsbuildstuff.co/learn/install-false-tread-stair-end-cap/) --- ## Reference Photos The following photos show examples of this type of work completed in the field. These serve as visual references for quality standards, proper installation techniques, and finished results. Showing 15 of 15 photos [![Raw wood horizontal rail with a corner post joint, unfinished stage](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2025/12/image000002.jpg-225x300.jpeg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2025/12/image000002.jpg.jpeg) Raw wood horizontal rail with a corner post joint, unfinished stage [![Interior staircase with taped wood treads, painted risers, and a black horizontal rod railing](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20230928_201331-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20230928_201331.jpg) Interior staircase with taped wood treads, painted risers, and a black horizontal rod railing [![Interior stairwell during installation with horizontal metal rod railing and a newel post](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231107_164404-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231107_164404.jpg) Interior stairwell during installation with horizontal metal rod railing and a newel post [![Rough framed wood plank stair treads with a horizontal slat railing, unfinished stage](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231004_163815-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231004_163815.jpg) Rough framed wood plank stair treads with a horizontal slat railing, unfinished stage [![Unfinished wood horizontal slat railing with a mitered end cap where the top rail meets the post.](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231006_132200-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231006_132200.jpg) Unfinished wood horizontal slat railing with a mitered end cap where the top rail meets the post. [![Horizontal wood slat railing installed on a staircase with a solid newel post, raw wood finish](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231006_132157-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231006_132157.jpg) Horizontal wood slat railing installed on a staircase with a solid newel post, raw wood finish [![Horizontal wood slat railing with a raw wood post and treads, pre-paint stage](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231004_145455-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20231004_145455.jpg) Horizontal wood slat railing with a raw wood post and treads, pre-paint stage [![Finished staircase with horizontal black metal rod railing between newel posts, gray treads](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240528_125712-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240528_125712.jpg) Finished staircase with horizontal black metal rod railing between newel posts, gray treads [![Finished interior staircase with horizontal metal rod railing and carpeted treads](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240528_125704-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240528_125704.jpg) Finished interior staircase with horizontal metal rod railing and carpeted treads [![Newel post and horizontal rail joinery, raw wood before finishing](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_100450-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_100450.jpg) Newel post and horizontal rail joinery, raw wood before finishing [![Small unfinished wood staircase and horizontal slat railing framed inside a room during construction.](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_151244-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_151244.jpg) Small unfinished wood staircase and horizontal slat railing framed inside a room during construction. [![Horizontal wood slat railing installed on a small unfinished stair platform](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_105801-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_105801.jpg) Horizontal wood slat railing installed on a small unfinished stair platform [![Raw wood framing joinery at a post and rail connection, rough carpentry stage](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_100443-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240920_100443.jpg) Raw wood framing joinery at a post and rail connection, rough carpentry stage [![Black metal stair balusters fastened into a diagonal rail post, treads covered during finish work](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20250217_200249-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20250217_200249.jpg) Black metal stair balusters fastened into a diagonal rail post, treads covered during finish work [![Black horizontal slat wall feature installed on a finished wall with painted trim and carpet flooring](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20241115_152043-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20241115_152043.jpg) Black horizontal slat wall feature installed on a finished wall with painted trim and carpet flooring × ‹ › Written by **David Hospodka**, Sun’s Up Construction David Hospodka learned finish carpentry from his father, alongside his brother Joel, and worked his way through college trimming houses. He then spent about ten years as a railroad bridge engineer, handling design, construction, maintenance and project management. He came back to finish carpentry full time in 2017. [About Let’s Build Stuff](https://letsbuildstuff.co/about/)