Intro

Under-stair space often turns into a dusty void. This guide shows you how to turn the space under your stairs into hidden storage DIY with a clean, strong build. You’ll plan the opening, frame safely, and install pull-outs or a flush door. We’ll cover tools, measurements, hardware, finishing, and mistakes to avoid. You can do most builds in 1–2 days. The result looks custom, hides clutter, and adds useful storage without changing the footprint of the home.

Quick Answer

You create hidden storage under stairs by laying out a safe opening, building a simple 2x frame, and adding plywood boxes or pull-outs on heavy-duty slides. Finish with a flush panel door, touch latches, and trim. Most jobs take 1–2 days with common tools and about $200–$600 in materials.

Table of Contents

• How to Turn the Space Under Your Stairs: Plan and Measure
• Under-Stair Hidden Storage: Tools and Materials
• Step-by-Step: Hidden Storage DIY Build
• Door and Drawer Options
• Finishing, Venting, and Safety
• Pricing and Client Tips
• Frequently Asked Questions

Key Takeaways

• Plan the opening away from the stair stringer by 3 in minimum.
• Use 3/4 in plywood, 1-5/8 in screws, and 100–150 lb slides.
• Typical cabinet depth: 20–24 in; common opening width: 24–36 in.
• Expect 6–8 hours for carpentry and 2–3 hours for finishing.
• A flush door with touch latches keeps the storage truly hidden.

How to Turn the Space Under Your Stairs: Plan and Measure

A good plan prevents rework. Spend time here.

• Confirm structure. The stair stringer carries load. Do not cut it. Keep any new opening at least 3 in away from the stringer edge. If there’s a framed wall, avoid cutting king studs without adding proper headers.
• Check for utilities. Use a stud finder and a non-contact voltage tester. Probe for pipes with a small inspection hole and a mirror. Mark any wires or vents to reroute.
• Pick access location. Most builds open from the side wall under the stringer. Aim for a clear rectangle: 24–36 in wide, 28–36 in high at the tall end, and 20–24 in deep. Stay at least 6 in below the bottom tread to keep a strong bearing line.
• Note code basics. In many homes, the underside of stairs to a habitable space needs a fire-rated layer. If you remove drywall on the stringer side, replace it with 5/8 in Type X drywall before finishing your cabinet.

Tip: If you’re also looking to streamline professional proposals, our guide on creating professional proposals pairs well with this kind of small add-on job.

Under-Stair Hidden Storage: Tools and Materials

You can do this with basic carpentry tools.

• Tools: circular saw or track saw, multi-tool, drill/driver, pocket-hole jig (optional), stud finder, level, square, oscillating tool, non-contact voltage tester, clamps, sander.
• Fasteners: 1-5/8 in #8 screws, 2-1/2 in structural screws for framing, brads for trim.
• Lumber: 2x4 for framing, 1x2 cleats.
• Panels: 3/4 in plywood for boxes and faces, 1/2 in plywood for backs.
• Hardware: Full-extension slides 20–24 in, 100–150 lb rating; or 2 in swivel casters if doing floor roll-outs. Concealed hinges or SOSS hinges for a hidden door. Magnetic touch latches.
• Finishes: primer, paint or clear coat, wood filler, caulk. 120 and 180 grit paper.

Step-by-Step: Hidden Storage DIY Build

Follow these numbered steps. Adjust sizes to your space.

1. Mark the Opening (30–45 minutes)

   • Level and plumb your lines. A common opening is 30 in wide by 34 in high at the tall end. Score drywall with a knife first for a clean cut.

2. Open the Cavity (30–60 minutes)

   • Use a multi-tool to cut drywall along your lines. Remove insulation carefully. Save baseboard for re-use.

3. Inspect and Protect (15 minutes)

   • Look for wires. Cap power if needed. Add temporary blocking if any studs were trimmed.

4. Frame the Rough Opening (45–60 minutes)

   • Build a 2x4 face frame inside the wall cavity. Add a header and sill. Tie new studs to existing at 16 in on center where possible. Use 2-1/2 in structural screws.

5. Install Backing and Cleats (20–30 minutes)

   • Add 1x2 cleats to the floor and wall where your boxes will sit. Keep cleats 1/2 in back from the face for a flush front later.

6. Build the Boxes (60–90 minutes)

   • Cut 3/4 in plywood: two sides, a bottom, and a face frame. Typical box: 22 in deep, 18 in wide, 28 in high. Use glue and 1-1/4 in screws or pocket screws. Add a 1/2 in back.

7. Choose Movement: Slides or Casters (20 minutes)

   • For heavy loads, mount 150 lb full-extension slides, 22–24 in long. For simple roll-outs, use 2 in casters on a base. Keep 1/8 in side clearance per slide maker specs.

8. Set Boxes and Adjust (20–30 minutes)

• Install magnetic touch latches at the top and bottom. Aim for 2 latches on wider doors. Adjust for a tight, rattle-free close.

11. Reinstall Trim and Baseboard (20–30 minutes)

• Miter baseboards across the new face. Add a false joint to hide the seam. Caulk gaps lightly.

12. Sand and Prepare for Finish (20–30 minutes)

• Break edges with 120 grit, then 180 grit. Fill screw holes. Vacuum dust.

Time check: Most pros spend 6–8 hours on steps 1–12. Painting and clear coat add 2–3 hours, plus dry time. This fits into a weekend.

Door and Drawer Options

Choose what fits the home and the load.

• Pull-Out Cubbies on Slides

  • Best for shoes, bags, and tools. Use 100–150 lb slides, 22 in long. Keep face panels flush with the wall. No visible handles. Use touch latches.

• Floor Roll-Outs on Casters

  • Simple and tough. Great for kids’ gear. Use 2 in casters with at least four per unit. Add a 3/4 in toe-kick face to hide wheels.

• Hinged Flush Door with Shelves

  • Clean look. Use three concealed hinges for a 36 in tall panel. Add 12 in deep shelves inside. Maintain a 1/8 in reveal for a “secret” look.

• Premium Hidden Hinges (SOSS)

  • True invisible hardware. Follow template precisely. Use at least three hinges for 3/4 in panels over 30 in tall.

Finishing, Venting, and Safety

Small details sell the job.

• Finish

  • Match the wall. Prime raw edges. Use enamel paint on faces for durability. Match sheen: eggshell on walls, semi-gloss on trim.

• Venting

  • Add two 1 in holes behind the baseboard or toe kick to avoid musty air. Screen the holes.

• Lighting

  • Add a 12V LED strip and a door switch. Warm white (3000K) looks natural.

• Safety

  • Do not notch the stringer. Replace any removed fire-rated board with 5/8 in Type X before closing. Keep a minimum 6 in clearance under the bottom tread. If in doubt, ask a local inspector.

Common mistakes to avoid:

• Oversizing the opening and weakening the wall.
• Using MDF near entry doors where moisture is common.
• Skipping full-extension slides. Short slides waste space.
• Forgetting a 1/8 in reveal, leading to rubbing and paint chips.

Pricing and Client Tips

Under-stair storage is a solid add-on. It’s fast and looks custom.

• Time and Cost

  • Many contractors price 1–2 days labor plus materials. Materials often run $200–$600, depending on slides and plywood grade.

• Options that Upsell

  • Soft-close slides, SOSS hinges, and LED lighting add value. Clear pricing avoids change orders.

• Simple Proposal Flow

  • Snap photos, note sizes, and speak your scope. Tools like Donizo let you capture details by voice, generate a clean proposal, and send it as a branded PDF with e-signature in minutes.

• Close and Bill

  • After approval, convert the signed proposal to an invoice fast using Donizo. This keeps cash flow smooth on small projects.

Internal linking opportunities:

• This pairs well with understanding project timelines for small add-ons.
• If pricing is tricky, see our notes on pricing strategies.
• For contractors wanting invoice templates that save time, we recommend a simple set you can reuse.

Frequently Asked Questions

Can I cut a stud or the stair stringer to make a bigger opening?

Avoid cutting the stringer. It carries stair loads. If you must cut a stud in a side wall, add a proper header and king/jack studs, just like a door opening. When in doubt, reduce the opening width or ask a local pro to assess.

Should I use slides or casters for pull-outs?

Slides give smoother motion and a cleaner look. Use 100–150 lb full-extension slides at 22–24 in. Casters are cheaper and tough but need a toe-kick face to hide wheels. For heavy bins, choose slides with higher ratings and screw into solid plywood edges.

What material is best: plywood or MDF?

Use 3/4 in plywood for strength and screw holding. MDF paints smooth but swells with moisture. Near entries or basements, plywood is safer. Edge-band plywood faces for a clean finish.

How long does this project take?

Most builds take 1–2 days. Plan on 6–8 hours for layout, framing, boxes, and faces. Add 2–3 hours for sanding and finishing, plus dry time. Custom hinges or lighting can add another hour.

Do I need to vent the cabinet?

A little airflow helps. Drill two 1 in holes behind the baseboard or toe kick. This prevents musty smells, especially near exterior doors. Screen the holes to keep bugs out.

Conclusion

Hidden storage under stairs is a high-impact, low-footprint upgrade. Plan the opening safely, build sturdy plywood boxes, use quality slides, and finish with a clean, flush face. Next steps: 1) Measure and mark an opening 24–36 in wide, 2) Build one test box at 22–24 in depth, 3) Choose slides rated 100–150 lb and set a 1/8 in reveal. For quick client buy-in, capture photos and scope, then send a branded proposal with e-signature through tools like Donizo. Build it right, and you’ll have storage that looks custom and works hard for years.