hide storage compartments under stairs (Pull-Out Carts)
Under-stair pull-out carts turn a hard-to-reach space into usable storage, but safe design starts with the stair structure and local code, not the cart. Measure the opening and sloped interior, choose a floor-supported or slide-supported system, protect required fire-rated surfaces, and keep services accessible. A careful fit check helps prevent binding, tipping, and damage.
A neat cart front can make an under-stair bay look like a simple cupboard. The hard part is what you cannot see: the slope, framing, wiring, and any required fire protection behind that opening. If you are short on space, a pull-out can make seasonal gear or household supplies easier to reach, without adding a bulky cabinet to the room.
I plan these spaces from the inside out. First I check what the stair enclosure must protect and what the bay must keep accessible. Then I measure the opening, choose the cart and hardware, and test the loaded unit. The goal is useful hidden storage that moves safely and does not weaken the stairs.
Planning the Under-Stair Bay and Checking Code Conditions
An under-stair bay is the enclosed space beneath a stair flight. Before adding a pull-out, identify its framing, finishes, and services, then check the building rules that apply. A cart opening does not by itself permit changes to stair framing or fire protection; confirm the approved approach with your local building department.
Start by locating stringers, supports, wall framing, electrical boxes, plumbing, and heating or return-air openings. Do not cut, notch, or drill a stringer or other structural member to gain room unless a qualified professional provides an approved detail. A small increase in cart width is not worth compromising a stair.
The adopted code matters. Under 2021 IRC §R302.7, the enclosed side of an accessible space beneath stairs must be protected with ½-inch gypsum board, where that provision applies. Your local jurisdiction may use a different code edition or amendments. Ask how the opening and cart must be detailed so they do not defeat the required protected assembly.
Keep service access in view, too. Under NEC §314.29, junction boxes must remain accessible without removing building finish. Do not hide one behind a cart or a permanent obstruction. Likewise, do not cover a return-air grille or block appliance access or manufacturer-required clearances.
Ordinary storage does not have a general IRC-required ventilation rate or CFM target. That does not make it safe to block an opening that serves a specific system. Identify what each grille or access point does before planning around it.
Next step: Make a sketch of the bay and mark framing, finishes, utilities, openings, and any code questions before choosing hardware.
Measuring the Opening, Cart Envelope, and Slide Clearances
The cart envelope is the full space the cart occupies as it moves, including its handles and contents. Measure both the entrance and the sloped interior at several points. The smallest usable dimensions, not the largest visible ones, determine whether the cart can enter, travel, and stop without rubbing.
Record the opening width near the floor and higher up, plus the clear height and depth at several points along the stair slope. Note baseboards, trim, door stops, floor changes, and anything that sticks into the bay. A phone photo with a tape measure in the frame can help you review the layout later, but it does not replace written measurements.
For side-mount slides, use the clearance in the current instructions for the exact model and length. As one example, the Accuride 3832 series specifies ½ inch (12.7 mm) of side space per side. With a measured 30-inch opening, subtracting those two clearances gives a preliminary 29-inch maximum cart width. Trim, uneven walls, and installation tolerances may require a narrower cart.
That calculation is a starting point, not a universal clearance rule. There is no single code-prescribed cart clearance for every under-stair bay. Check the slide maker’s required space, mounting orientation, and full-extension dimensions. Also confirm that the cart can pass through the opening and that its widest point will not strike the slope.
| Measurement or check | How to use it |
|---|---|
| Narrowest opening width | Set the maximum entry width before subtracting hardware clearance |
| Interior width along the travel path | Find tight spots caused by the slope or framing |
| Usable depth | Check how far the cart can extend without hitting a wall or blocking a route |
| Height at front, middle, and rear | Confirm the cart and stored items fit beneath the stair slope |
| Slide side clearance | Subtract the exact amount in the chosen model’s instructions |
| Full-extension space | Check that the cart can open without hitting a door, furniture, or required access |
For example, a bay may accept a wide cart at the entrance but narrow sharply near the back. A cart that fits only when empty may also fail once handles, bins, or stored items project beyond its frame. Test the intended load shape, not just the bare cart.
Next step: Write down the tightest measurement in each direction, then compare those figures with the cart and hardware instructions before buying materials.
Framing, Mounting Slides, and Finishing the Pull-Out
A slide-supported cart uses paired hardware to carry and guide a moving unit. A floor-supported cart carries its weight on wheels or casters. These are different designs: choose one deliberately, follow the hardware maker’s instructions, and do not assume a slide rating proves that the whole assembly is safe.
Build the cart square and rigid so it does not rack as it moves. Use materials and joints suited to the load, and keep the base level. For a wheeled cart, select casters designed for the expected load and floor, and use suitable guides or stops only when their makers allow that use. Do not treat ordinary drawer slides as guide rails for a wheeled cart unless the manufacturer approves that arrangement.
For a slide-supported design, anchor the slide fasteners into suitable structural material, such as sound backing or a framed cabinet structure. Gypsum board alone is not a structural anchor. Follow the slide maker’s fastener, orientation, and mounting instructions, and confirm that the stair framing itself will not be cut or weakened.
Accuride’s 3832 series is specified at 100 pounds per pair. That figure applies to the slide pair under the maker’s stated conditions; it is not a rating for a homemade cart, its fasteners, its backing, or the stair structure. Include the cart’s weight and contents in the moving load, and keep them within the applicable hardware limit. Do not combine parts based on a rating alone.
Before finishing, fit a stop or other positive retention feature so the cart cannot roll or slide out unexpectedly. Keep handles within the measured envelope. If the cart must be removable, follow the hardware instructions for safe removal and reinstallation, and make sure it cannot release during normal use.
Next step: Dry-fit the empty cart, check its full travel, then load it gradually and retest before storing heavy or fragile items.
Verifying Fire Protection, Access, and Loaded Operation
A final inspection checks more than whether the cart rolls. It confirms that the opening, moving hardware, stored items, and enclosure still meet the plan. Test the complete system at full travel and with a realistic load, then look for binding, tipping, loose fasteners, blocked services, or damage to required fire-protective surfaces.
Pay special attention to the opening through the under-stair enclosure. Where IRC §R302.7 applies, the required ½-inch gypsum protection on the enclosed side must remain as required by the approved assembly. Do not assume a cart front or a piece of board around the opening meets that requirement. Ask your local building official or a qualified building professional how the specific opening should be protected.
Use these checks before putting the cart into regular service:
- Move it through its full travel several times while empty, then loaded.
- Check that wheels or slides stay aligned and do not bind at the narrowest point.
- Confirm that the cart does not tip, sway excessively, or pull away from its mount.
- Inspect fasteners and backing for movement.
- Confirm the cart and its contents do not cover a junction box, HVAC opening, or required appliance access.
- Look for cracks, gaps, or damage in gypsum board or other required protective finishes.
Stop if the cart catches, fasteners shift, or the enclosure finish is damaged. Find the cause before using it again; forcing a loaded cart can worsen the problem.
Next step: Keep the final measurements, hardware instructions, and any code guidance with your home records so future changes do not block access or undo the protection.
Worked Layout Examples: Choosing a Cart for the Bay
These examples are planning exercises, not reports of specific completed installations. They show how different bay shapes affect a cart choice. Measure your own space and verify the hardware and code requirements before building.
Example A: Wide opening, narrowing interior. Imagine a bay with a 30-inch opening and a tighter interior farther back. If the chosen side-mount slides require ½ inch on each side, the preliminary cart width is no more than 29 inches at the opening. The inside measurement may require an even narrower cart. A shorter unit can be a better fit than one that fills the entire visible opening.
Example B: Low, sloped space. Imagine a bay with enough width for a cart but limited height near the back. Measure height at the front, middle, and rear, then keep the cart and its contents below the lowest point along the travel path. Low bins may use the space better than tall containers, but handles and lids must also clear the slope.
| Bay condition | Suitable starting point | Main risk to check |
|---|---|---|
| Wide opening, tight interior | Narrower cart with measured travel path | Cart binds at the back |
| Low sloping ceiling | Short-height cart or low containers | Items or handles hit the stair underside |
| Uneven floor | Leveling plan or suitable wheels | Cart rolls, rocks, or shifts |
| Junction box in the bay | Layout that preserves access | Cart blocks access required by code |
| Fire-protective lining at opening | Approved opening detail | Cart installation defeats the required assembly |
In my planning work, the most common early mistake is sizing to the doorway alone. A cart can fit through the opening and still fail at the slope, floor, or service access. Treat the full path as the usable space, not just the front face.
Next step: Choose a cart layout only after checking the complete travel path and resolving any code or service-access concerns.
Conclusion and FAQ
A well-planned under-stair pull-out can make hidden space useful without changing the stair structure. Measure the whole bay, select hardware for the intended load, anchor it correctly, and preserve required protection and access. If the opening affects a protected enclosure or the structure, get local guidance before installation.
Can I install a pull-out cart under any staircase?
No. Check the bay’s framing, utilities, dimensions, local code, and fire protection first. Do not alter structural members without an approved detail.
How much side clearance do drawer slides need?
It depends on the slide model. For example, Accuride 3832 slides specify ½ inch per side. Verify the current instructions for your exact model.
Does ½-inch gypsum board always apply beneath stairs?
The 2021 IRC §R302.7 requires it on the enclosed side of an accessible under-stair space where that provision applies. Check your locally adopted code and amendments.
Can I fasten slides to drywall?
No. Fasteners need suitable structural backing. Gypsum board alone should not carry the slide mounting load.
Does a 100-pound slide rating mean my cart can hold 100 pounds?
Not necessarily. The Accuride 3832 rating is for a slide pair under specified conditions, not the entire cart, fasteners, backing, or stair structure.
Should the cart use wheels or drawer slides?
Choose a system designed for the load and movement. Wheels carry weight on the floor; slides carry and guide a cart according to their instructions. Do not use slides as guides for a wheeled cart unless the maker approves it.
Can I cover a junction box or return-air grille with the cart?
No. Keep junction boxes accessible as required by NEC §314.29, and do not block HVAC openings or required appliance access.
How do I stop the cart from tipping or rolling out?
Build a rigid, square cart, use properly installed hardware, and add a suitable stop or retention feature. Test it empty and loaded before regular use.
Is ventilation required for ordinary under-stair storage?
There is no general IRC ventilation-rate requirement for ordinary storage. Still, do not block a grille or opening that serves a system.
What should I do if the cart binds after loading?
Stop using it and inspect the travel path, alignment, fasteners, and load. Correct the cause before moving the cart again.
(This article was written by one of our staff writers, Robert Kensington. Visit our Meet the Team page.)
