Stairs/Handrails #

Skill Level: Expert (Level 3) #

Estimated Time: 3-5 Hours #

Introduction: How to Build Garage Steps #

Ready to build garage steps? Whether you’re a first-time DIYer or a seasoned carpenter, basic garage steps are one of the simplest stair builds — typically just 1 to 3 risers descending from the house entry to the garage floor, without a landing platform. Despite being “basic,” the fundamentals of stair math and construction still apply. In fact, this is often the very first stair project a carpenter builds, and it teaches every fundamental concept used on larger stairways: total rise, individual riser calculation, stringer layout, the “drop” adjustment, and proper anchoring.

When you build garage steps, they’re commonly designed for height differences between the house floor and garage floor that are relatively small — usually between 7″ (one riser) and about 22″ (three risers). For larger height differences, or when a door swings outward over the stairs, a landing is required (see the companion guide for steps with a landing). Most residential garage entries fall in the 14″ to 22″ range, which means 2 or 3 risers.

This guide covers the basic configuration: 2 stringers with open risers (no riser boards). For wider stairs that need a third stringer, closed riser finishes, or handrail installation, see the supplemental guides at the bottom of this page.

Even with just 2 or 3 steps, getting consistent riser heights is critical for safety. Human feet are remarkably sensitive to riser height differences — even a 1/4″ variance between steps causes a noticeable stumble. Building code limits riser variance to 3/8″ for good reason: inconsistent risers are a leading cause of stairway falls. The most common mistake is treating basic garage steps as “just a couple of steps” and eyeballing the measurements instead of doing proper stair calculations.

When you build garage steps, they face unique environmental challenges. They sit on a concrete slab, which means moisture protection is essential. Any wood touching the concrete must be pressure-treated. The concrete surface may not be level (garages are intentionally sloped toward the door for drainage), which means your bottom measurements need to account for that slope. And because garage steps take heavy daily traffic — groceries, kids, dogs, muddy boots — they need to be built solid.

Before You Build Garage Steps #

Prerequisites #

• Garage floor poured and fully cured (at least 28 days for new concrete)
• Doorway/entry point established with framing complete
• Finished floor installed in the house (or its exact thickness known if not yet installed) — you must measure total rise to the FINISHED floor, not subfloor
• Door swing direction confirmed — if the door swings toward the garage, it must clear the steps when fully open (if it doesn’t, you may need a landing instead)
• Check local building codes for stair requirements — most follow IRC but some jurisdictions have amendments
• Determine if a handrail is required (see Code Requirements section below)

Code Requirements (IRC Residential) #

Even when you build garage steps with just a few short risers, building codes apply. Understanding these requirements before you start prevents costly rework:

• Maximum riser height: 7-3/4″ (most codes) — aim for 7″ to 7-1/2″ for comfort
• Minimum tread depth: 10″ (measured from nosing to nosing, or nosing to riser if no nosing on the step above)
• Maximum riser variance: 3/8″ between the tallest and shortest riser on the entire stairway
• Tread nosing projection: 3/4″ minimum, 1-1/4″ maximum beyond the riser face (if nosing is used)
• Minimum stair width: 36″ clear between walls or handrail
• Headroom: 6′-8″ minimum measured vertically from the stair nosing to the ceiling/header above
• Handrail requirement: Required when there are 4 or more risers in most jurisdictions. Some jurisdictions require a graspable handrail for 3 or more risers. When you build garage steps with 1-3 risers, you may not be required to install one, but check your local code. Even if not required, a handrail is always a good idea for elderly household members or when carrying items
• Guard rail requirement: If the side of the stairway is open and more than 30″ above the adjacent floor, a guard rail (42″ high) is required. This rarely applies to basic garage steps

Understanding Stair Math #

When you build garage steps, the layout is pure math. Understanding these terms prevents every common stair-building mistake:

• Total rise: The vertical distance from the garage floor to the top of the finished house floor. When you build garage steps, this is ALWAYS measured to the FINISHED floor — if carpet, tile, or hardwood isn’t installed yet, you must add its thickness to your subfloor measurement
• Individual riser height: Total rise ÷ number of risers = individual riser height. Every single riser must be this height (within 3/8″)
• Total run: The horizontal distance the stairway covers from the face of the house wall to the front edge of the bottom tread. Total run = (number of treads) × tread depth. Remember: the number of treads is usually one LESS than the number of risers (the house floor is the top tread)
• Tread depth: Minimum 10″. The flat horizontal surface you step on. Deeper treads (11-12″) feel more comfortable. Garage steps often use 11-1/4″ treads (the full width of a 2×12)
• The “drop” adjustment: The bottom of the stringer must be cut shorter by exactly ONE tread thickness (typically 3/4″ for plywood, 1-1/2″ for 2x material). Without this adjustment, the bottom riser will be taller than the rest by the thickness of the tread — this is the #1 stair-building mistake
• Nosing: The front edge of the tread that overhangs the riser below. Provides extra foot room. Typically 3/4″ to 1-1/4″ projection

Pro Tip: The “comfort rule” for stairs says riser + tread should equal approximately 17″ to 18″. When you build garage steps, a 7″ riser works well with a 10″ to 11″ tread (7 + 11 = 18). A 7.5″ riser pairs with a 10″ tread (7.5 + 10 = 17.5). Use this rule as a gut-check on your layout — stairs that violate this range feel either cramped or awkwardly stretched.

Garage Steps: Example Stair Calculations #

Let’s walk through two common scenarios:

Scenario 1: Total rise = 14-1/2″

• 14.5″ ÷ 7″ target = 2.07 → Round to 2 risers
• 14.5″ ÷ 2 = 7-1/4″ per riser ✅ Under 7-3/4″ max
• Number of treads = 2 risers − 1 = 1 tread (the house floor is the top tread)
• Total run = 1 tread × 10″ = 10″ (the stairs only extend 10″ from the wall)
• Drop adjustment: subtract 3/4″ from bottom riser if using 3/4″ plywood tread

Scenario 2: Total rise = 21″

• 21″ ÷ 7″ = 3.0 → 3 risers
• 21″ ÷ 3 = 7″ per riser ✅ Perfect
• Number of treads = 3 risers − 1 = 2 treads
• Total run = 2 treads × 10″ = 20″ from the wall face
• Make sure there’s room in the garage for 20″ of stair projection. If cars park close to the wall, deeper treads like 11″ push the stairs to 22″ — verify clearance before committing

Open vs. Closed Risers #

Before you build garage steps, decide whether you want open or closed risers:

• Open risers (no riser boards): Faster to build, less material, and you can see/reach under the stairs for storage. Common when you build garage steps. However, open risers on stairs with more than 30″ total rise may require that the opening not allow a 4″ sphere to pass through (child safety code) — rarely an issue with basic garage steps
• Closed risers (riser boards installed): Cleaner, more finished look. Adds structural rigidity. Requires additional material. See the closed riser supplemental for full installation details

Tools Required to Build Garage Steps #

Power Tools #

• Circular saw (7-1/4″ blade minimum — essential when you build garage steps for cutting 2×12 stringers)
• Drill/driver (for Tapcon anchors and tread screws)
• Hammer drill or rotary hammer (for drilling into concrete — standard drills won’t work for Tapcons in cured concrete)
• Jigsaw (optional — helpful for finishing inside corner cuts that the circular saw can’t reach)

Hand Tools #

• Framing square (the single most important tool when you build garage steps — buy a quality steel one, not aluminum)
• Stair gauges (small brass clamps that attach to the framing square — they make layout repeatable and foolproof)
• Tape measure (25-foot minimum)
• Pencil (carpenter’s pencil — flat so it won’t roll off the stringer)
• Speed square (for marking 90° cut lines on treads and risers)
• 4-foot level (for checking treads for level after installation)
• Handsaw (for finishing the inside corners where the circular saw blade can’t reach — a sharp Japanese pull saw works great for this)
• Chalk line (for marking the plumb cut line at the top of the stringer and for layout reference)
• Combination square (for checking the depth of your circular saw cut and marking the nosing overhang)

Supplies #

• 16d framing nails or 3″ structural screws (GRK, SPAX, or Simpson Strong-Tie — for attaching stringers to house framing)
• 2-1/2″ wood screws (for attaching treads to stringers — #8 or #10 gauge)
• Construction adhesive — PL Premium or similar polyurethane adhesive (for treads-to-stringers bond; prevents squeaks and adds enormous rigidity)
• 3/16″ × 2-3/4″ Tapcon concrete screws (for anchoring kicker plate to concrete — buy hex-head, not Phillips)
• 5/32″ concrete drill bit (pilot bit for Tapcon screws — must match the Tapcon size exactly; it usually comes packaged with the screws)
• Simpson Strong-Tie stair stringer connector (LSC model or equivalent — provides a code-approved mechanical connection between the stringer top and the house framing)
• Pressure-treated 2×4 (for kicker plate on concrete — MUST be ground-contact rated PT lumber, not standard framing lumber)
• Shims (for leveling stringers and treads if the garage floor or wall is out of plumb/level)

Materials #

• 2×12 lumber (for stringers): Select structural-grade, kiln-dried lumber. Inspect for straightness, crown, and large knots in the tread/riser cut areas — a knot at a cut weakens the stringer. You need 2 stringers minimum, 3 for stairs wider than 36″. Each stringer requires approximately 14″ of board length per riser (a 3-riser stair uses about 3.5 feet of 2×12)
• Tread material options:
  • 3/4″ CDX plywood — economical, strong, easy to cut. Paint or cover with rubber stair tread covers for grip
  • 2×12 or 2×10 lumber — more traditional look, beefier, can be stained. Use a single board per tread for best results
  • Laminated stair tread blanks (available at lumber yards) — pre-finished with bullnose edge, premium option
  • Pressure-treated lumber — required if the bottom tread is close to the concrete floor in high-moisture garages
• Riser material (closed riser configurations only): See the closed riser supplemental for material details

How to Build Garage Steps: 9-Step Process #

Step 1: Measure Total Rise Accurately #

This is the most critical measurement when you build garage steps. An error here makes every riser wrong.

Place a straight 2×4 on the house floor at the doorway and extend it out over the garage floor. Level it with a 4-foot level. Measure DOWN from the bottom of the leveled 2×4 to the garage floor directly below. This is your total rise. Take this measurement at multiple points across the stair width — the garage floor may slope (garages are typically sloped 1/4″ per foot toward the garage door for drainage). Use the measurement where the stringers will actually land.

Now divide by your target riser height. When you build garage steps, the ideal residential riser height is 7″ to 7-1/2″ for comfort. You’ll rarely get a number that divides evenly — round to the nearest whole number of risers, then recalculate:

• Total rise = 15-3/4″ (15.75″)
• 15.75″ ÷ 7″ = 2.25 → Round to 2 risers
• 15.75″ ÷ 2 = 7-7/8″ per riser
• ⚠️ That’s 7-7/8″ — OVER the 7-3/4″ maximum! Try 3 risers instead
• 15.75″ ÷ 3 = 5-1/4″ per riser ✅ Code compliant, but feels a bit short

In this example, 3 risers at 5-1/4″ is code-compliant but will feel a little shallow. That’s fine — it’s just unusual. The alternative (2 risers at 7-7/8″) violates code.

Pro Tip: When you build garage steps, always measure to the TOP of the finished floor, not the subfloor. If the house floor hasn’t been installed yet, add its thickness. If it’s 3/4″ hardwood over subfloor, your total rise is subfloor measurement + 3/4″. Getting this wrong by even 3/4″ means your top riser will feel different from the rest — and it will fail inspection.

Step 2: Lay Out the First Stringer #

This is where the framing square and stair gauges earn their keep when you build garage steps. The stringer layout determines everything — if the layout is wrong, the stair is wrong.

Setting up the framing square:

• Clamp one stair gauge to the tongue (narrow side) of the framing square at your riser height (the number you calculated in Step 1)
• Clamp the other stair gauge to the body (wide side) at your tread depth (10″ minimum — 11-1/4″ if using full 2×12 treads)
• Both gauges should hook on the edge of the 2×12 so the square sits at the same position every time you slide it along

Marking the layout:

• Lay the 2×12 on sawhorses with the crown (natural bow) facing UP — the crown side becomes the top of the stringer
• Start at one end. Position the framing square with both stair gauges hooked on the top edge of the board
• Trace along both the tongue (riser line) and body (tread line) with a sharp pencil
• Slide the square along the board until the tongue aligns with the end of the previous tread line, and trace the next riser/tread pair
• Repeat for each step. For 2 risers, you’ll mark 2 riser/tread pairs. For 3 risers, 3 pairs

Critical: The “drop” adjustment

After marking the layout, you MUST adjust the bottom of the stringer. The bottom riser must be reduced by exactly one tread thickness. Why? Because when the tread is installed on the bottom step, it adds height. Without the drop adjustment, the bottom riser (floor to first tread surface) would be taller than all the others by the tread thickness.

• Using 3/4″ plywood treads? → Shorten the bottom of the stringer by 3/4″
• Using 2x lumber treads (1-1/2″ actual)? → Shorten by 1-1/2″
• Mark a line parallel to the original bottom cut, offset up by the tread thickness. Cut on this new line

Top cut (plumb cut): At the top of the stringer, extend the last riser line straight up to the top edge of the board. This vertical (plumb) cut butts against the house framing. The top of the stringer should sit flush against the rim joist or wall framing at the exact height where the house floor meets the garage opening.

Pro Tip: Before cutting ANYTHING, set the marked 2×12 in position against the wall. Check the critical measurement: does the top of the first tread cut line up exactly with the house floor level? If yes, your layout is correct. If not, recheck your math. It takes 2 minutes to verify and saves hours of rework.

Step 3: Cut the Stringers #

Cutting stringers requires precision and is the most skill-intensive part of learning to build garage steps. You’re removing large triangular sections from the 2×12, and the remaining wood forms the structural skeleton of the stairs.

• Set the circular saw blade depth to cut through the full 1-1/2″ thickness of the 2×12. Use a sharp blade — a dull blade wanders and makes wavy cuts
• Cut along the tread and riser lines carefully. The circular saw blade is round, so it CANNOT cut all the way into the inside corner where the tread and riser lines meet. STOP the circular saw cut at the corner — do NOT overcut past the lines. Overcutting weakens the stringer because you’ve removed wood from the structural portion
• Finish the inside corners with a handsaw. Use a sharp handsaw or Japanese pull saw to carefully cut the remaining material at each inside corner where the circular saw couldn’t reach. Cut precisely to the pencil line — no further
• Cut the bottom (with drop adjustment) and the top plumb cut

How many stringers?

• Stairs up to 36″ wide: 2 stringers (one on each side) — this is what this guide covers
• Stairs wider than 36″ need a center stringer. See the 3-stringer supplemental for center stringer layout, installation, and blocking details

After cutting the first stringer, use it as a template for the rest. Clamp it on top of the next 2×12 and trace the pattern. Or better yet, cut the first one, test-fit it (Step 4), verify it’s correct, THEN use it as a template. Never mass-produce stringers from an unverified pattern.

After all stringers are cut, stack them on top of each other on a flat surface. All tread cuts and riser cuts should align within 1/16″. If one stringer is off, use it as the center stringer (where the error is least visible) or re-cut it.

Pro Tip: For basic 2-step stairs, you only need about 3 feet of 2×12 per stringer. But buy a full-length board (8′ or 10′) and cut from the straightest, clearest section. Reject boards with large knots in the area where the tread/riser cuts fall — a knot at a cut point is a weak point that can crack under load. Look at the board from the end to check for twist.

Pro Tip: After cutting, check that the remaining “throat” of the stringer (the narrowest section of wood remaining after the tread/riser cuts) is at least 3-1/2″. Code requires this minimum. If your layout produces a throat less than 3-1/2″, you may need to use a wider board or adjust the tread depth.

Step 4: Dry-Fit the First Stringer #

Before drilling into concrete or attaching anything permanently, test-fit the first stringer:

• Set the stringer in position with the top plumb cut against the house framing
• Place a level on each tread cut — they should all read level (or very close, accounting for the garage floor slope)
• Measure the first riser from the garage floor to the top of the first tread cut — this should equal your calculated riser height MINUS the tread thickness (because the drop adjustment was made, the tread material will bring it to the correct height)
• Temporarily place a piece of tread material on the first tread cut. Now measure from the garage floor to the top of the tread. This should equal your calculated riser height exactly
• Measure from the top of the tread to the house floor — this should equal your calculated riser height for the top riser
• If any measurement is off by more than 1/4″, find the error before proceeding

Pro Tip: This dry-fit step is where most stair-building mistakes get caught. NEVER skip it. It takes 5 minutes and can save you from rebuilding the entire staircase. Walk up and down the dry-fitted stringer (carefully, holding onto the wall) — your feet will immediately tell you if a riser height is off.

Step 5: Install the Kicker Plate #

The kicker plate anchors the bottom of the stringers to the concrete floor. This is a critical step when you build garage steps — without it, the stairs can slide forward when you step on them.

• Cut a pressure-treated 2×4 to the full width of the stairway
• Position it on the garage floor where the bottom of the stringers will land — use your dry-fitted stringer to mark the exact location
• Drill pilot holes through the PT 2×4 and into the concrete with a hammer drill and 5/32″ masonry bit. Drill at least 1-3/4″ into the concrete (the Tapcon needs minimum 1″ embedment plus the 1-1/2″ wood thickness)
• Drive Tapcon screws through the 2×4 into the concrete — minimum 4 screws for a 36″ wide stair, spaced evenly
• Test the plate by trying to wiggle it side to side and push it forward — it should be completely solid. If it moves, add more Tapcons

Pro Tip: Blow out the concrete dust from each drilled hole with a compressed air nozzle or a puff from your mouth BEFORE driving the Tapcon. Dust in the hole reduces the screw’s grip. Also, drive Tapcons with a drill/driver on low speed — high speed overheats the screw and strips the concrete threads.

Step 6: Set and Attach the Stringers #

Now attach the stringers permanently at both the bottom (to the kicker plate) and the top (to the house framing).

Bottom attachment:

• Set each stringer on the kicker plate with the bottom cut flat on the PT 2×4
• Toenail or toe-screw through the stringer into the kicker plate — 2 screws per side (4 per stringer)
• Alternatively, use a Simpson A34 or A35 framing angle on each side of each stringer to connect it to the kicker plate — this is the strongest method

Top attachment:

• Best method — Simpson LSC stair connector: This metal hanger wraps around the stringer and fastens to the rim joist or header. It provides a mechanical connection that won’t pull out. Follow the manufacturer’s nailing schedule (specific nail type and count)
• Alternative — direct fastening: Drive 3″ structural screws through the stringer’s plumb cut into the rim joist. Use at least 4 screws per stringer. This works but is not as strong as a metal hanger
• Another option — ledger board: Mount a 2×4 ledger horizontally on the house framing at the height where the stringer tops land. Set the stringers on the ledger and screw through the back. This distributes the load across a wider area

After attaching, check every tread cut with a level. If a stringer has shifted or tilted during attachment, shim it before proceeding.

For wider stairs that require a center stringer, see the 3-stringer supplemental for blocking and additional attachment details.

Step 7: Install Risers (If Using Closed Style) #

This step applies only to closed riser configurations. If you’re building open riser stairs (this guide), skip to Step 8.

For closed riser installation details — material selection, cutting, sequencing (risers go in BEFORE treads), and attachment — see the closed riser supplemental.

Step 8: Install the Treads #

Treads take the load and are the final major step when you build garage steps. They need to be securely attached with BOTH adhesive and mechanical fasteners.

• Apply a generous bead of construction adhesive to each stringer’s tread cut. Use a zigzag pattern for coverage — don’t just run a thin line
• Set the tread material in place. Position it with the correct nosing overhang on the front edge (3/4″ to 1-1/4″). The tread should also overhang the outside stringers by 1″ to 1-1/2″ on each side (or be flush if against a wall)
• Drive 2-1/2″ screws down through the tread into each stringer — 2 screws per stringer minimum. Pre-drill if using hardwood treads to prevent splitting
• If using closed risers (see closed riser supplemental), also drive a screw through the back of the tread into the riser top edge
• Check each tread with a level immediately after fastening. Shim under the tread at the stringer if needed

Pro Tip: Even on basic garage steps, ALWAYS glue AND screw the treads. Construction adhesive prevents squeaks and adds enormous rigidity. Screws alone will loosen over time with daily foot traffic — garage steps take hundreds of trips per week. Glue alone has no clamping force. Both together create a permanent, squeak-free joint.

Pro Tip: For plywood treads, lightly roundover the front edge with sandpaper or a router and 1/4″ roundover bit. A sharp plywood edge is uncomfortable on bare feet and splinters easily. For a finished look, apply iron-on edge banding to the exposed plywood edges.

Step 9: Final Verification and Finishing #

Before calling the job done, every set of garage steps needs a thorough verification:

• Measure every riser height (floor to tread, tread to tread, top tread to floor). Maximum variance allowed: 3/8″ between the tallest and shortest riser
• Walk up and down the stairs 5-6 times. Each step should feel identical. Your body will instantly feel an inconsistent riser
• Jump on each tread — no flexing, no bouncing, no creaking. If there’s flex, add a center stringer
• Check that the nosing projection is consistent on every tread
• If treads are to be painted or stained, now is the time. Sand any rough spots first. Use a paint with grit additive or apply non-slip tread strips for safety — smooth paint on stairs creates a slip hazard, especially in garages where floors get wet

Optional finishing touches:

• Install rubber stair treads or non-slip tape — garages get wet, and slipping on stairs is dangerous
• Caulk where the stringers meet the wall (if against a wall) to prevent dirt/moisture accumulation
• Paint exposed stringer faces and the underside if the stairs are open — aesthetics and moisture protection
• Consider adding a handrail even if code doesn’t require it (see Related Guides)

Quality Check #

• ✅ All risers within 3/8″ of each other (measure and record each one)
• ✅ Treads level side-to-side and front-to-back
• ✅ Stringers solid with zero flex when walking
• ✅ Bottom securely anchored to concrete (kicker plate doesn’t move)
• ✅ Top securely attached to house framing (no separation gap when weight applied)
• ✅ No squeaking under foot traffic
• ✅ Comfortable to walk — all steps feel identical (close your eyes and walk up/down)
• ✅ Nosing projection consistent on all treads (3/4″ to 1-1/4″)
• ✅ Tread width matches stair opening with correct overhang on sides
• ✅ No overcuts visible on stringer faces (cosmetic defect and structural concern)
• ✅ All fasteners countersunk or flush (no protruding screw heads on treads)
• ✅ Stringer throat width is at least 3-1/2″ at narrowest point
• ✅ Headroom clearance meets 6′-8″ minimum under any header or soffit

Troubleshooting Common Garage Steps Problems #

Steps feel bouncy or flex when walking #

The most common fix is adding a center stringer — see the 3-stringer supplemental for the full process. If the span is narrow (under 30″) and still flexing, the tread material may be too thin — upgrade from 3/4″ plywood to 2x lumber or double up the plywood.

Bottom riser feels taller/shorter than the others #

The most common stair-building error. If the bottom riser feels TALLER: you forgot to make the drop adjustment (subtract one tread thickness from the bottom of the stringer). Remove the stairs, cut the drop adjustment from the bottom of each stringer. If the bottom riser feels SHORTER: you made the drop adjustment but with the wrong measurement (e.g., subtracted 3/4″ but used 1-1/2″ thick treads), or you double-subtracted. Re-measure and correct.

Top riser is different from the others #

The total rise measurement was wrong. You either measured to the subfloor instead of the finished floor, or the finished floor has been installed since you measured and it changed the total rise. The only fix is to re-measure the actual total rise and re-cut the stringers. There are no shortcuts — an incorrect top riser cannot be shimmed or trimmed to match.

Stringers slide on the concrete floor #

The kicker plate is not properly anchored. Possible causes: Tapcon screws were driven into crumbling concrete (common near control joints or slab edges), the pilot holes weren’t deep enough, or not enough screws were used. Remove the kicker plate, drill new holes in solid concrete (move away from cracks or edges), blow out the dust, and re-anchor. For problematic concrete, consider using concrete wedge anchors or drop-in anchors instead of Tapcons for a more permanent grip.

Treads squeak when walked on #

Construction adhesive wasn’t used, has failed, or wasn’t given time to cure before heavy use. Drive additional screws through the tread into each stringer. For persistent squeaks, drive a screw from underneath (through the stringer tread cut up into the tread) which pulls the tread tight against the stringer. Injecting adhesive through a drilled hole on the underside can also help fill gaps between the tread and stringer.

Tread nosing overhang is inconsistent #

The tread wasn’t properly positioned before fastening, or stringers aren’t perfectly aligned. If only slightly off, you can plane or sand the nosing to match. If significantly off, remove the tread, reposition, and reattach. Use a combination square set to the desired overhang as a guide when positioning each tread.

Treads don’t sit level even though stringers were level during dry-fit #

The stringers shifted during final attachment. Check that the stringers are still plumb and the tread cuts are level. If a stringer has twisted or tilted, loosen its fasteners and re-set it. Blocking between stringers prevents this twisting during and after installation. Also verify the kicker plate is level — if the garage floor slopes (which it usually does), the kicker plate may need to be shimmed on one end.

Can’t get Tapcon screws to hold in the concrete #

Several possible causes: the pilot hole is too shallow (drill at least 1/4″ deeper than the screw will embed), the concrete is old and crumbling (move to a different spot or use epoxy anchors instead), the hole wasn’t cleaned of dust (compressed air or vacuum before driving), or the screw was driven too fast and overheated (use low speed on the drill). If Tapcons consistently fail, switch to 1/4″ sleeve anchors or wedge anchors which grip differently and work better in weak concrete.

Stringer has a visible overcut past the tread/riser corner #

The circular saw was run past the layout line at the inside corner. This is cosmetic AND structural — overcuts weaken the stringer’s throat. If the overcut is minor (less than 1/2″ past the line), it’s usually fine structurally but should be filled with wood filler if visible. If the overcut is significant, cut a new stringer. To prevent this on future stringers, stop the circular saw 1/2″ BEFORE the corner and finish with a handsaw.

Safety Considerations #

• Non-slip surfaces: Garage floors get wet from rain, snow, and car wash water. Apply non-slip tread covers, grip tape, or use paint with anti-slip additive on treads. Smooth-painted plywood treads in a garage are a lawsuit waiting to happen
• Lighting: Ensure adequate lighting at the top and bottom of the stairs. A motion-activated light near the garage entry door prevents missteps in the dark
• Handrail: Even if code doesn’t require one for 2-3 risers, consider installing a handrail — especially if elderly family members or children use the stairs, or when carrying heavy groceries/items. See the related guide for wall-mounted handrails
• Clearance: Make sure the stairs don’t interfere with car parking. Mark the stair footprint on the garage floor with tape before building so you can see how close your car comes
• Fire code: In many jurisdictions, the door between the garage and house must be fire-rated (20-minute minimum) and self-closing. Building steps doesn’t change this, but while you’re working in the area, verify the door has a self-closer installed

External Resources #

• IRC R311.7 — Stairway Code Requirements (International Code Council)
• Simpson Strong-Tie LSC Stair Stringer Connector — the recommended connector for attaching stringers to house framing
• How to Use Tapcon Concrete Anchors — manufacturer guide for proper concrete fastening