This article is about how to build deck stair railings. In this project we show you how to choose the proper materials and tools for building deck stair railings, as without a good diy step by step guide it would be a complex task for any unexperienced home improver. Nevertheless, if you pay attention to all our tips and techniques that we use throughout the project, you will be able to get the job done in a professional manner.
Before building deck stair railings, you have to learn how to attach deck posts, otherwise you won’t be able to install the bottom rail, hand rail and balusters for your deck stairs. After you have built and installed the deck stairs, you have to attach the stair railings as to make it practical and give it a nice appearance.
In order to build stair railings, you need the following:
- 4×3 lumber - RAILS
- 2×3 lumber - X-SHAPED BALUSTERS
- 6-8” screws - WOOD SCREWS FOR RAILS
- 3” screws - WOOD SCREWS FOR BALUSTERS
- Primer, Stain
- Level, carpentry pencil, l-square, tape measure
- Rubber hammer, hammer, C-clamps
- Circular saw / jigsaw, miter saw
- Drill machinery and bits
- Electric screwdriver with torque control
- Read safety and disclaimer pages
- Select with great care the lumber, otherwise the railings would look bad
- Before fastening the posts, make sure they are plumb
- Pre-drill holes in the components, to prevent wood from splitting
Building deck stair bottom rail
Before building and installing deck stair railings, we have to attach the deck posts on the deck surface. Consequently, according to the structure of your deck you can either anchor the posts on the floor using post anchors, or you can fasten them to the deck joists using lag screws.
Smart tip: Use a level to make sure the posts are aligned and plumb.
Next, we have to mark on the deck posts where we will install the bottom rail. However, we have to make sure the bottom rail of the deck stairs is aligned with the mail deck bottom rail.
Consequently, we have to use an l-square to mark on the deck post the top edge of the bottom rail. Pay attention to this operation if you want a neat look for your diy deck stair railings project.
Next, we have to continue the mark on the next face of the deck post, as to be able to install properly the bottom rail.
Use an l-square and a carpentry pencil, to be able to erase the mark after the installation of the stair railings.
Smart tip: In order to get a clean look, we have to align the top of the stair bottom rail with the top edge of the deck bottom rail.
After we have marked the guidance line, we have to measure the distance from the post anchor / floor surface, as to be able to transpose it to the other post of the deck stair railing.
Smart tip: Use a tape measurement along the edge of the deck post.
With the previous distance in mind, mark a line on the lower stair post in the same way you have done before. This line will also represent the top edge of the bottom rail. In this way, the deck stair railings will be symmetric and have a nice look.
Smart tip: Pay attention to this operation otherwise the angle of your stair railings will not match the angle of the slope of the stairs.
Next we have to position the 4×3 lumber over the two guidance lines we have drawn on the deck stair posts. Remember that the top of the lumber has to be aligned with the lines on each post.
After you have set the lumber in the proper position, you can either ask another person to mark the cut lines by using a pencil, or you can fix them firmly with two C-clamps and then mark them by yourself.
In this image you can see the marks on the 3×4 lumber. The cut lines have to be parallel, so if you notice that something is wrong, you have to redo the previous step, in order to build the stair railings in a professional manner.
In order to make precision cuts, you have to use a miter saw. Although it is an expensive power tool, we recommend you to buy or rent one, as it is the right tool for this job. You could try cutting the bottom rail with a circular saw, but you will have to make, in most cases, two cuts, one on each side of the bottom rail.
For building the deck stair railings, we use common pressure treated lumber and we also recommend you to make the same choice, as it looks very good and it is very durable.
Next, we have to fasten the bottom rail to the deck stair posts. In order to be able to do this, we have used a good drill machinery and a sharp drill bit. Therefore, we have to make pilot holes in the deck posts before installing the 6-8” wood screws.
Smart tip: Make sure you drill through the deck posts from one end to the other, as to be able to fasten the bottom rail in a professional manner. Otherwise, you might get a gap between the bottom rail and the deck post, especially if you don’t cut the rail properly.
For a neat look we recommend you to countersink the head of the screws, using a countersink bit.
Countersink bits are quite cheap, come in many forms and types, and make a significant difference when they are used properly.
Smart tip: Use a good drill machinery with torque control, as to be able to increase or decrease the speed of the drill if necessarily.
After we have countersunk the heads of the wood screws, we obtained the result you can see in the image.
Do not countersink too deep in the wooden post, just go 1/2” in the wood posts.
Smart tip: After you have finished installing the deck stair railings, you could mask the screw heads with wood putty.
Next, in order to finish installing the bottom rail, we have to fasten it to the deck posts with two wood screws. The screws have to be at least 6-8”, as to be able to fix the bottom rail firmly.
In order to get the job done in a professional manner, you have to use two wood screws and an electric screwdriver with torque control.
Smart tip: First drive in the screws using the screwdriver at low speeds, then as the screw gets in the wood deeper, you could increase the speed.
Installing deck stair handrail
After we have finished installing the bottom rail, we have to continue the project by installing the handrail. Consequently, we have to cut another piece of 3×4 lumber, with the same dimensions as the bottom rail.
In addition, we have to align the top of the deck stair handrail with the top of the platform handrail.
Smart tip: When drilling pilot holes, we should hold the drill machinery at angle, as to be able to insert the screws alongside the handrail.
The next step of our project is to drive in the wood screws, using the same electric screwdriver. In addition, we also countersunk the holes, as to mask the heads of the wood screws.
Smart tip: When installing the handrail, make sure you align it with the deck posts. In order to get the handrail secured properly, we recommend you to drive in two wood screws.
After we have built and installed the deck stair railings, we got the result it can be seen in the image. You should be able to notice that the two railings are parallel one with other, and in addition have the same slope as the stairs.
After you have installed the bottom rail and the handrail, you should also use a level to check if the deck post are still plumb. There are cases in which, due to poor installation, after you fix the railings, the posts could be slightly moved from the right position.
Smart tip: Continue with the installation of the deck stair balusters. Make sure the bottom rail is parallel with the top rail.
Installing deck stair railings
After we have installed the deck stair railings, it is time to build and install the balusters. Consequently, you have to choose the design of your balusters before starting the project. In our case we have to build x-shaped balusters, as to fit with the rest of the house design, but you can adjust the designs, to fit your needs and tastes.
Smart tip: We have used 2×3 lumber to build the deck balusters. Align the lumber with the top of the bottom rail and with the bottom of the handrail, and draw cut lines along the post edges. If you want to install vertical balusters, you could also use 2×2 lumber. If you work by yourself, you can fix the lumber into the proper position, by using 2 C-clamps.
Next we have to cut the balusters using a miter saw. In most of the cases, you can also cut the balusters with a regular circular saw or jig saw, but the most precise cut can be made with a miter saw.
Smart tip: Make sure the blade of the miter saw is over the cut line, otherwise the balusters won’t fit between the deck stair posts.
Install the first deck stair railing using an electric screwdriver and 3” wood screws. At first, you should use the electric screwdriver at low speeds, and as the screw enters in the wood, you have to increase the speed.
Smart tip: Before installing the wood screws, you have to make pilot holes, otherwise you risk damaging the wood (it might crack).
Installing railings at the bottom of the deck railing could prove to be a difficult task, as that place is inaccessible in most of the cases, due to the low angle. Consequently, the only way to fix the baluster is to drill a hole holding the drill machinery diagonally.
Smart tip: Countersink the head of the screws, in order to obtain a neat look.
After we have finished installing the balusters, our deck stair railings look as you can see in the image.
Smart tip: Use a good wood primer to protect the wood from moisture. In this way, you will enjoy your diy deck stair railings for a long time.
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