Measuring Understair Drawer Openings Properly

A few millimetres can be the difference between an understair drawer that glides out neatly and one that catches on a skirting board, rubs the floor or leaves an awkward gap. Measuring understair drawer openings is not simply a matter of taking the width and height of the space below the stairs. The staircase slope, structural timbers, floor level and intended drawer mechanism all affect the finished design. For homeowners in Edinburgh, West Lothian and Central Scotland, understair storage is often the answer to a familiar problem: a valuable part of the home is present, but difficult to use well. A bespoke drawer system can turn that space into organised storage for shoes, coats, cleaning equipment, bags or household essentials. It needs to be designed around the property, rather than forced into a standard size. Start with the finished opening, not the empty void The visible opening is the section framed by the surrounding joinery where each drawer front will sit. It is not necessarily the same as the internal cavity beneath the stairs. A wall may not be straight, the floor may rise or fall, and the underside of the staircase usually slopes. Before dimensions are taken, decide where the finished face of the cabinetry will be positioned. This is especially relevant where the understair area has existing skirting, plasterwork, pipe boxing or a door lining nearby. In some homes, retaining original features is the right choice. In others, removing and replacing sections of skirting creates a cleaner built-in result. Neither approach is automatically better. The right option depends on the character of the hallway and how integrated you want the finished storage to look. Measure from the planned finished floor level, rather than assuming the current floor surface is final. If new flooring is due to be installed, its thickness matters. Timber flooring, tiles, underlay and carpet can each alter the available clearance at the bottom of a drawer. The key measurements for understair drawers A professional survey records more than one measurement at each point. The area under a staircase rarely forms a perfect triangle, and relying on a single width, height and depth can create expensive errors later. Begin by measuring the overall available width along the wall beneath the stairs. Take this measurement at the floor, at mid-height and close to the underside of the stairs. Walls can taper slightly, particularly in older Edinburgh properties where plaster may be uneven. Next, record the depth from the proposed drawer front to the rear wall. Measure at several heights. A staircase stringer, projecting newel post, service pipe or uneven rear wall can reduce usable drawer depth. The deepest part of the void is not always the practical depth for the drawer box. The changing height is the most important dimension. Measure vertically from the finished floor level to the underside of the stair structure at regular intervals along the run. Measurements every 300mm to 400mm usually give a clear picture of the slope, although a more detailed survey may be needed for a complex stair layout. It helps to mark each point on a simple sketch. Include the distance from a fixed starting point, such as the face of the newel post, alongside the height at that location. This allows the slope to be translated accurately into the cabinet design rather than guessed from an overall diagonal measurement. Measure the structure, not just the plasterboard Some staircases have a smooth plasterboard soffit beneath them, while others expose or conceal structural components at different depths. The lowest fixed point controls the available space. If the underside is to be opened for storage, the joinery must account for the actual stair construction, including the stringer and any framing. Do not cut, drill into or remove stair components to gain a little extra room. Staircases are structural elements. Bespoke storage should work around the structure safely and neatly, not compromise it. Allow for the drawer front and the drawer box The drawer opening is the visible space. The drawer box is the moving unit behind it. They need different allowances. A drawer front may overlap the cabinet sides or sit within a framed opening, depending on the chosen style. An inset front offers crisp, even reveals but demands greater precision because the gaps around it are visible. An overlay front can be more forgiving and may suit a contemporary handleless arrangement, but it still requires careful alignment. Behind the front, the drawer box needs clearance for the runners and enough room to move without fouling the cabinet, floor or staircase. The required allowance depends on the runner system selected. Side-mounted runners, concealed soft-close runners and heavy-duty pull-out systems all have different requirements. This is why drawer hardware should be chosen during design, not as an afterthought once the openings have been made. Measuring understair drawer openings around the stair slope The practical challenge is deciding where one drawer should end and the next should begin. A tall full-height drawer at the bottom of the stairs may be useful for coats or a vacuum cleaner, while shallower drawers towards the slope can suit shoes, hats, gloves or pet supplies. The configuration should follow how the household actually lives. The lowest section under the staircase can be deceptively restrictive. Even if the opening looks wide enough from the front, the drawer needs enough internal height and depth to be useful. A shallow pull-out that stores very little is rarely good value. In certain properties, a fixed panel or narrow cupboard at the lowest point creates a better visual balance than forcing in a small drawer. The angle of the slope also affects the shape of the drawer box. Drawer fronts are often rectangular, while the cabinet behind them is stepped or angled to fit beneath the stairs. This keeps the outside clean and ordered, but it means each drawer may have a different internal capacity. A bespoke design makes this variation work for you rather than hiding it behind identical fronts. When marking proposed openings, allow a consistent gap between drawer fronts. Small, even reveals give the installation a considered finish and allow for seasonal movement in timber and minor variations in the building. Overly tight gaps may look impressive on a drawing but can cause rubbing once the home warms, cools and settles through the year. Check movement space in the hallway A drawer can fit perfectly within the staircase and still be impractical if it blocks a front door, hallway route or nearby cupboard when opened. Measure the full extension of each drawer, including the front thickness and handle projection. Then consider how people move through the space at busy times, such as the school run or when guests arrive. For narrow hallways, shorter drawers or a combination of drawers and doors may be more suitable than deep full-extension pull-outs. Full extension provides excellent access to the back of the drawer, but it takes more room in front of the unit. The choice is a balance between storage capacity and clear circulation. Also check for radiators, electrical sockets, alarm controls and access panels. These can sometimes be incorporated into the joinery, but they should not be obstructed. Heating controls and electrical connections need sensible access for maintenance. Why a site survey matters A tape measure and a rough note are useful for an initial conversation, but they are not a substitute for a detailed site survey. Older homes can include walls that are out of square, floors that dip, and staircases with details that are not visible until the area is examined closely. Newer homes can present their own constraints, including service runs and standardised stair components. A master joiner will assess the space as a complete installation: the staircase, surrounding finishes, desired storage use, hardware, access and visual style. At Install Joinery Scotland, that approach means the drawer openings are planned alongside the cabinet construction and fitted finish, rather than treated as isolated measurements. A simple measuring checklist before your consultation Before arranging a design discussion, take a few photographs of the staircase from directly in front and from each side. Note the overall width, the maximum depth, the height at several points beneath the slope, and any visible obstacles such as radiators or sockets. It is also helpful to think about what you want to store, because a household needing boot storage has very different requirements from one looking for a hidden utility cupboard. Avoid ordering standard drawer units in advance. Their fixed dimensions rarely suit the changing geometry beneath a staircase, and adapting them can waste both space and money. Made-to-measure joinery earns its value by using the available volume intelligently while keeping the exterior calm, precise and appropriate to the home. The best understair drawers do not announce the compromises required to build them. They open easily, hold what you need and sit naturally within the hallway. Careful measurement is where that quiet, well-crafted result begins.