What Is Under-Staircase Pull-Out Concealment? (Ball Bearing Slides)
An under-stair pull-out is a drawer that travels on side-mounted ball-bearing slides within the space below a stair. Its safe design starts with the stair’s structure, required clearances, and fire protection, then sizes the drawer to the chosen slide’s instructions. It must not cut stringers, block service access, or replace required gypsum protection with a decorative front.
A common mistake is sizing the drawer from the visible opening, then buying slides to fit. That reverses the process: slide clearances and mounting rules vary by model, and the space behind the finish may contain framing, utilities, or required fire protection. I treat this as a small built-in cabinet project, not a box that can be pushed into any gap.
Planning the Under-Stair Pull-Out
An under-stair pull-out is a removable storage drawer fitted into an available stair enclosure and supported by side-mounted slides. Planning means checking the stair framing, enclosure layers, nearby services, and moving path before cutting finishes. The design must preserve the stair’s required geometry and comply with the locally adopted code and slide-maker instructions.
What the pull-out includes
The main parts are the drawer box, a front panel, a pair of ball-bearing slides, and solid supports for mounting those slides. Ball bearings let the slide members travel with less friction. A “full-extension” slide allows most of the drawer to come out, but travel and load limits depend on its model.
The drawer may look like a flush panel when closed, but its appearance does not make it a fire-protection layer. Nor should a front panel be treated as a structural stair part. The stair and enclosure keep their intended function; the pull-out is an added cabinet assembly.
Check the stair and enclosure first
Before opening a wall or stair enclosure, identify the stringers, blocking, utilities, and finish layers. A stringer is the sloped structural member that supports stair treads. Do not cut or notch one to gain drawer space. If framing is hidden, use appropriate inspection methods or ask a qualified carpenter or building professional to identify it.
IRC R302.7 requires the enclosed side of the under-stair surface to be protected with ½-inch gypsum board where the space under the stairs is enclosed and usable. Confirm the adopted code edition and local amendments. If installing the drawer would remove or interrupt this protection, stop and resolve the enclosure detail with the building official or a qualified designer before cutting.
Measuring Access, Stair Clearances, and Slide Space
Measure the actual opening and the full path the drawer will use, rather than relying on nominal dimensions from a plan. Record the clear width, height, depth, slope, and nearby obstructions. Also check that the proposed installation does not affect required stair headroom, width, fire protection, or access to building services.
Record the moving envelope
The moving envelope is the full space occupied by the drawer as it opens and closes. Measure from the planned front face to the rear limit of travel, and note trim, doors, handrails, and objects that could block the drawer. Check the opening at several points: under stairs, framing and finish are often not perfectly square.
IRC R311.7.2 generally sets minimum stairway headroom at 6 ft 8 in., subject to code measurement rules and exceptions. IRC R311.7.1 generally requires 36 in. of clear stair width above handrail height, with applicable handrail provisions and local rules. Do not let a projecting drawer or handle intrude on required clear space.
Choose slides, then calculate the drawer
Select a slide model before fixing drawer width or depth. Many side-mount ball-bearing slides need ½ in. of clearance on each side, but that is not a universal rule. Use the product’s datasheet for its exact side gap, length, extension, mounting position, and load rating.
For a simple width calculation:
- Measure the finished opening between the slide-mounting surfaces.
- Subtract the maker’s required clearance on both sides.
- Use the result as the maximum drawer-box width, then check the maker’s fit and tolerance notes.
For example, if a specific slide calls for ½ in. per side, the nominal drawer box is 1 in. narrower than the measured opening. This example is only a calculation, not a universal slide specification. Verify the dimensions for the selected model and the actual opening.
| Check | What to measure or verify | Why it matters |
|---|---|---|
| Opening | Clear width, height, depth, and squareness | The drawer must fit without binding |
| Slide fit | Model-specific side clearance and mounting geometry | Nominal dimensions do not define slide fit |
| Travel | Slide length, extension, and rear clearance | The drawer must open without hitting structure |
| Stair | Required width and headroom under local rules | The pull-out must not obstruct the stair |
| Services | Wires, pipes, and access panels | Storage must not block service or maintenance |
Case study: a sloped enclosure
Consider a hypothetical stair enclosure with a wide opening near the floor but a shallow rear section under the stair slope. A deep rectangular drawer could fit at the front and still strike the sloped framing as it travels. I would map the slope at the drawer’s top and rear edges, then choose a permitted slide length and box shape that clear the obstruction.
That example illustrates why a single depth measurement is not enough. Confirm the entire path, including the drawer front and handle. If the usable space is too shallow for the selected slide’s required length or mounting geometry, choose a shorter compatible slide or a different storage layout rather than forcing the assembly.
Framing and Installing Ball-Bearing Slides
Installation begins with sound, square supports fixed to verified structural framing. The slides must be parallel, at the maker’s specified height, and set to the correct spacing. Finish gypsum alone is not a reliable slide support. Keep fasteners and supports clear of stair members, utilities, and required protection layers.
Build supports without altering the stair
After confirming the mounting points, install level, stable support cleats or panels that attach to suitable framing. The exact fasteners and support details depend on the framing and slide instructions. Do not attach a loaded drawer slide to gypsum board alone, and do not assume trim or a thin finish panel can carry the load.
Check that the support faces are parallel and that the slide pair will be level with each other. Small alignment errors can cause binding or uneven travel. If the stair framing does not offer safe mounting points, have a qualified professional design a support method; do not cut a stringer to create one.
Fit the slides and drawer
Follow the slide maker’s sequence for separating slide members, setting them in place, and attaching them to the drawer and cabinet supports. Keep the specified clearance on both sides. Use the listed fastener type and location, and do not substitute a shorter fastener where the instructions require a particular engagement.
Install the drawer without its intended load first. It should move through its travel without scraping, twisting, or colliding with the stair enclosure. Fit the front only after the box runs correctly. Adjust its gaps so the face sits evenly, while keeping the front removable for inspection or repair.
Verifying Load, Travel, and Code Protection
A finished pull-out is ready only after its movement, attachment, load, and enclosure details have been checked. Slide ratings and allowed drawer dimensions vary by product, so use the chosen manufacturer’s published limits and installation instructions. Confirm that the work preserves stair clearances, required protection, and access to utilities.
Test load and retention
The slide’s published rating must cover the loaded drawer, not just the empty box. Include the drawer, front, hardware, and stored contents when assessing the total load. Follow the maker’s rating conditions; do not infer capacity from the slide’s size or appearance, or assume a rating applies to every mounting orientation.
Load the drawer in a controlled way and test it across its travel. Watch for sag, loose fasteners, noise, or binding. Confirm positive retention if the slide model provides it, and avoid storing more than the product’s stated limit. Recheck fasteners and alignment after the first loaded test.
Inspect the enclosure and access
A decorative drawer front does not replace gypsum protection required by IRC R302.7. If the pull-out interrupts the required layer, do not cover the gap with trim and assume the detail is compliant. Confirm the solution with the local building official or a qualified designer, based on the adopted code and the specific enclosure.
Also keep electrical, plumbing, and other service access usable. Do not bury a junction box, shutoff, or required access point behind a drawer that cannot be removed as needed. If a service runs through the proposed cavity, revise the layout or obtain qualified guidance before proceeding.
Case study: a flush front with a protected enclosure
In a second hypothetical layout, the drawer face aligns with the surrounding finish, but the planned opening crosses the gypsum layer under an enclosed stair. A neat seam would not solve the protection issue. I would pause the cabinet work and confirm an approved enclosure detail before cutting or moving that layer.
This is the key difference between a tidy finish and a compliant assembly. The drawer can be removable and visually flush, but the building protection still has to be addressed as its own requirement. Document the chosen detail and inspect it before closing the finish.
Conclusion and FAQ
A reliable under-stair pull-out starts with the stair and enclosure, not the drawer. Survey the structure and services, select the slide model, calculate the box from its instructions, then install and test the assembly. Preserve required clearances and fire protection, and ask the building official or a qualified designer when an enclosure detail is uncertain.
What is an under-stair pull-out?
It is a drawer installed in usable space below a stair and moved on slides, often ball-bearing slides. Its box, supports, and travel path must fit the actual enclosure. The installation must also preserve the stair’s structural members, required clearance, services, and any required under-stair fire protection.
Do ball-bearing slides always need ½ inch per side?
No. Many side-mount models call for ½ inch per side, but slide clearances vary by product. Check the selected slide’s installation sheet and measure the actual opening between mounting faces. Calculate drawer width from those instructions rather than applying a common clearance as if it were universal.
How do I size the drawer?
Choose the slide first, then measure the finished opening and subtract the manufacturer’s required clearance on both sides. Check drawer depth against slide length, extension, and rear obstructions. Confirm all dimensions at more than one point, because an under-stair opening may be sloped or out of square.
Can I cut a stair stringer to make room?
Do not cut or notch a stair stringer to create drawer space. Stringers support the stair, and altering one can affect its structural performance. If the existing framing leaves too little room for the pull-out, revise the storage design or consult a qualified building professional about safe options.
Does a drawer front replace under-stair gypsum board?
No. A decorative front is not a substitute for the protection required by IRC R302.7 where it applies. A pull-out that interrupts the required gypsum layer needs a compliant enclosure detail. Confirm the adopted code and local requirements with the building official or a qualified designer before cutting.
What slide load rating should I choose?
Choose a slide whose published rating covers the fully loaded drawer under the manufacturer’s stated installation conditions. Count the box, front, hardware, and stored items. Do not estimate capacity from appearance or assume a rating applies to a different slide length, orientation, or mounting method.
Can a pull-out reduce stair width or headroom?
It must not obstruct required stair geometry. IRC R311.7.2 generally sets 6 ft 8 in. minimum headroom, and IRC R311.7.1 generally requires 36 in. clear width above handrail height, subject to applicable rules and exceptions. Check the locally adopted code and measure the installed condition.
What should I do if utilities are in the cavity?
Do not conceal or obstruct wiring, plumbing, shutoffs, junction boxes, or required service access. Identify the services before framing, and revise the drawer layout if the travel path conflicts with them. If relocation or protection is needed, consult a qualified trade professional and follow local requirements.
(This article was written by one of our staff writers, Garrett Vance. Visit our Meet the Team page.)
