In this tutorial I will show you how to build stair stringers, how to build steps with blocks, and how to install deck stairs. This is part 1 of a 3 part series on how to build a set of stairs.
When building a set of stairs, it’s best to start by figuring out the stair stringers. The stringers are the main support for the steps that are attached to the wall at the bottom and the hand railings at the top. In this tutorial, you’ll learn how to build your own stair stringers using treated lumber.
Stair stringers. One of the most common methods is to build a stringer first and then nail it to the wall framing with metal hangers. The stringer can be made from 2x4s for a simple stairway or 2x6s for a more elaborate design. For an even more elaborate design, you can use 2x8s or even 2x10s.
Stair risers. The next step is to install the risers on top of the stringers using construction adhesive or other fasteners. You can also use metal brackets if you want your stairway to look more like a commercial staircase.
Steps with blocks. Another option is to build steps with blocks — such as concrete blocks or bricks — and attach them directly to the wall framing without any stringers at all. When attaching these blocks directly to the wall, use metal hangers instead of nails so they won’t pull out over time due to lateral forces from people walking up and down stairs (such as when children jump off the top step).
Stair Stringers
🧱 How It Works
• Stringers run under the steps and support treads (horizontal) and risers (vertical).
• There are two common types:
– Open (cut) – sawtooth shape, exposes treads from the sidе.
– Closed (boxed) – treads fit into routed grooves inside the stringer.
📋 Materials or Tools Needed
- Lumber: 2×12 boards are standard for strength.
- Pressure-treated wood: Resistant to rot/warping—essential for outdoor use.
- Alternate options: Treated LVLs, steel stringers are usable too.
- Cutting tools: Circular saw with a sharp blade; framing square with stair gauges.
⚙️ Step-by-Step Instructions
- Choose wood
- PT lumber is best for decks; pick straight, minimal-knots boards.
- If you only have untreated lumber, apply a high-quality sealer or paint.
- Measure rise & run
- Total rise ÷ desired riser height = number of steps.
- Use a framing/combination square or chalk-line datum rather than warped board edges.
- Mark stringer pattern
- Use a full-size square and stair gauges—small ones aren’t accurate.
- Clamp square or board to your datum line for precision.
- Cut stringers
- Use a sharp blade; clean cuts matter .
- For open stringers: cut the sawtooth.
- For closed: route dadoes for treads and risers.
- Install stringers
- Attach top end to deck or ledger; space stringers ≤ 18″ OC (for 36″ stairs use three).
- Bottom support: concrete blocks or footings—not bare ground. PT wood degrades in soil over time.
- Attach treads and risers
- Use corrosion-resistant fasteners. Leave small overhangs on treads.
✅ Pros and Cons
| Option | Pros | Cons |
|---|---|---|
| PT 2×12 lumber | Durable, code-approved, widely available | Slightly weaker grade; need to pick best boards |
| Untreated DF with sealer | Strong, high quality | Needs more maintenance |
| Treated LVL / Steel | Resistant to shrinkage and warping | More expensive; less local availability |
🔍 Compared with Similar Methods or Products
- Pre-cut stringers save time—just trim to fit your rise .
- Steel or LVL stringers are pricier but eliminate PT wood shrinkage issues.
💡 Common Mistakes to Avoid
• Laying layout off a warped board edge—use a chalk-line datum.
• Using small speed squares—full-size is more accurate.
• Cutting with a dull blade—leads to poor fit and weak joints.
• Resting stringers on bare soil—causes rot and sinking.
👷 Who Should Use This
Anyone building deck stairs or exterior steps who wants strong, code-compliant, long-lasting results.
🧰 Expert Tips
- Crown wood upward and snap a datum line before marking stringers.
- Use stair gauges and clamp your square for consistent marks.
- Always use a sharp blade on your circular saw.
- Provide stable support under stringers—block or footing—don’t let PT wood touch the earth .
📌 Quick Facts
- 2×12 lumber is standard for strength
- PT wood is recommended; choose straight, minimal-knots boards .
- Open stringers spaced ≤ 18″; closed types span longer .
- Datum-line marking avoids layout errors .
📊 Visual Table Above (Pros/Cons)
How to build stairs
Material Type | Characteristics | Pros | Cons |
|---|---|---|---|
Wood |
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Steel |
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Concrete |
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The stringer is a horizontal board at the bottom of each flight of stairs that supports the top treads and risers (the vertical parts) of the steps. It’s also known as a stringboard or understair stringer because it runs under each step rather than above it like most other components in a stairway system do. In many homes, you’ll find stringer boards attached underneath stair treads using screws or nails driven into predrilled holes in each side of those boards’ middle portions so that they
Building stairs is a fairly simple job, but it has to be done right. Here are some tips to help you make the right choices when building stairs.
Stair stringers are the main structural component supporting the treads and risers of your stairs. The typical stringer size is 2 x 8, but you can use 2 x 10 lumber as well, which will provide greater strength.
The best way to build stairs with stringers is to attach them to both sides of each step with a bolt-on hanger bracket. This ensures that the stringer won’t move out of position if one end sags more than the other during installation or after years of use and abuse.
Another option is to cut notches into the tops of the stair stringers so they fit snugly over the tops of each step riser. But this technique isn’t as secure or efficient as using hanger brackets because it requires more lumber and takes longer to install.
How to Build Steps with Blocks
Building steps is a simple project that can be done with a few tools and a little time. If you are building steps for a deck or porch, you will need to install them into the side of your home or into the ground. You should also consider how many stairs you want, as well as their height and width.
Steps come in different sizes, so if you need a custom staircase, make sure that you are able to get the right size before cutting it down. Also, if you want to build stair stringers yourself, make sure that they fit properly into your home before cutting them down.
Materials Needed:
Wooden blocks or 2x4s (depending on what kind of steps you want)
If you want to build stairs with blocks, it’s important to understand how to construct a set of stairs using them. There are several different methods of constructing steps using block, but all are based on similar principles. The first step is the most critical one: determining how many steps you’ll need and where they should go.
Steps are measured by their height and depth. The depth of a step varies depending on the materials used in its construction, but the standard depth for a concrete block step is 18 inches; this allows enough room for someone with boots on to get up and down easily.
The height of each step depends on the design of your staircase. In general terms, though, it’s best if each step is taller than it is wide. This makes it easier for occupants to navigate while wearing shoes or boots with heels or heavy soles that can slip on narrow stair risers (the sloped part between steps).
Stairs have two primary components: stringers and stringers. Stringers are solid pieces of wood (usually 2x12s or 2x10s) that run up the center of each flight of stairs; these serve as support for the treads and risers as well as providing a surface area for attaching handrails and
Stair stringers are the main structure or framework for steps. They are also called treads, landings, and risers. The stair stringer can be made from wood or metal. Many times, the stairs will have a combination of both materials.
Steps can be built in many different styles. It all depends on what the homeowner is looking for. Some people want their stairs to look like they came out of a magazine, while others just want something functional and affordable. The most important thing to remember when building your own steps is that they need to be safe and secure.
If you’re thinking about building your own steps, here are some helpful tips:
Prepare Your Area – Before you start building your steps, make sure that you have plenty of space and room around where you plan on putting them so that you don’t end up with any issues later on down the road when installing them into place.
Choose the Right Materials – When choosing materials for your stair stringer, there are several things that you need to consider before making your final decision on what material would work best for your project. These include cost effectiveness, ease of installation, durability and strength as well as aesthetic appeal
1. Lay out the stair stringer and mark the holes for the railing posts. The front edge of these posts should be flush with the front face of your stringer.
2. Using a hammer drill, bore a hole at each of these locations.
3. Set aside one of the railing posts and go back to drilling holes in your stair stringer for the block-and-spacer system that will support it.
4. Cut blocks of 2 x 4 to fit between your railing posts (see illustration). Space them along the length of your stairway so there’s at least 1/4 in between each one – more if you want a more open feel to your steps.
5. Position one block between each pair of posts (see illustration). It’s OK if they extend beyond the face of the post – it will help keep them stable as you build up other blocks around them later on.
Step 1: Lay out the stair stringer.
Step 2: Cut the stairs.
Step 3: Attach the stairs to the landing and floor.
Step 4: Install safety handrails on each step.
Step 5: Finish the staircase with a durable finish like polyurethane or varnish.