How Deep Should Alcove Cabinets Be? Balancing Storage and Room Space

For standard book storage, 220–250mm internal depth accommodates both paperback and hardback formats comfortably. For AV equipment (streaming boxes, hard drives, amplifiers), a minimum of 300mm is required and 350mm provides useful clearance for cabling at the rear. For clothing and soft storage in a bedroom alcove, 450–500mm enables use of standard clothes hangers. For general display and decorative objects, 200–220mm is sufficient and does not project excessively into the room.

In rooms where the alcove does not project far enough to accommodate the required storage depth, the cabinet can project forward of the chimney breast face by 50–100mm without looking out of place. Beyond 100mm of projection, the unit begins to feel furniture-like rather than architectural. In very tight rooms — hallways and compact living rooms particularly — a shallower cabinet with well-specified interior organisation provides better room proportions than a deep cabinet that dominates the space.

Depth sounds like a single number, but no alcove has just one. I measure the projection of the chimney breast in at least three places — top, middle and bottom of the run — because period walls are rarely flat, and a figure taken only at skirting height can be 15–20mm out from the depth available higher up. Where the discrepancy is significant, the cabinet carcass is designed to the tightest point and the back panel scribed to follow the wall behind it, rather than building to the most generous measurement and finding a gap along one edge on installation day.

I also check the depth at the sides of the alcove separately from the centre, since side walls can bow or the reveal can taper slightly from front to back. None of this is unusual — it is simply what a genuine period property gives you — and it is exactly why a bespoke measured survey produces a better result than working from a single dimension taken off a tape measure at one point.

Across the Victorian and Edwardian terraces and semis I work on around Ascot, Windsor, Bracknell and Wokingham, chimney breast projection typically falls between 300mm and 400mm, though I have measured plenty outside that range — some as shallow as 250mm, others closer to 450mm where the original flue arrangement was more substantial. This single dimension effectively sets the ceiling for how deep a fitted cabinet can go without projecting into the room, so it is the first figure I establish at survey, before any conversation about internal layout begins.

1930s and post-war housing tends to have shallower chimney breasts, sometimes under 300mm, which pushes the depth conversation towards projecting cabinets or a more disciplined internal layout rather than simply relying on the alcove's natural depth.

Almost every alcove unit I build steps back as it rises — deeper base cupboards, typically 300–450mm, holding AV equipment or bulkier storage, with shallower shelving above at 220–300mm for books and display. This is not just a space-saving trick, though it is that too: pulling the upper shelving back from the room creates a genuine cupboard top ledge at a useful working height, keeps books within comfortable reach rather than receding into shadow, and makes the whole composition feel lighter as it rises rather than looming over the room.

The step itself is a detail worth getting right — a clean, deliberate offset with a properly finished top edge reads as considered joinery, while an uneven or fudged transition between depths looks like an afterthought. I set the step out at design stage so it lines up with a consistent reveal all the way along the run.

The carcass depth you specify is not the same as the depth the finished cabinet actually occupies. A cupboard door typically adds around 20mm to the overall depth, and a projecting handle adds a further 25–35mm on top of that — figures that matter in a tight room where every centimetre is contested. Push-to-open doors remove the handle projection entirely, which is one of the reasons I specify them so often on units that sit close to a sofa, a walkway, or another piece of furniture.

It is worth deciding on door and handle style before finalising the internal depth, since a design drawn around a flush push-to-open front will feel noticeably tighter if a client later asks for a traditional protruding handle instead.

Skirting running into the alcove reduces the usable depth by 20–25mm unless it is removed before the unit goes in. There are two honest routes: remove the skirting entirely and run the unit to the bare wall for maximum depth, accepting a small amount of making good afterwards, or scribe the plinth and back edge of the cabinet over the existing skirting profile and lose that depth. Both are legitimate approaches and I price both at survey so the client can weigh the trade-off — a little extra depth against a little extra disruption.

Picture rails, dado rails and coving intruding into the alcove at height are dealt with the same way — either scribed around or removed, decided case by case depending on how much depth or height is actually at stake.

Every socket, pipe and radiator valve inside the alcove is measured and photographed at survey, because these are exactly the kind of detail that determines real usable depth rather than the nominal figure on a drawing. Where a socket sits proud of the wall, the back panel of the cabinet is either spaced forward locally with an access cut-out, or — more often the better long-term solution — an electrician relocates the socket into a position where it becomes genuinely useful inside the finished cabinet rather than an obstruction behind it.

Pipework for radiators or old gas fittings is treated the same way: identified early, discussed with the client, and either boxed with proper access or coordinated with a plumber before the joinery is finalised. Nothing gets sealed in behind a fixed panel where it cannot be reached again.

Streaming boxes, routers, amplifiers and games consoles need a genuine minimum of 300mm internal depth, and 350mm is more comfortable once the plugs and the inevitable loop of cable behind each unit are accounted for. Depth is only half the story with AV equipment, though — this kit runs warm, and a sealed cupboard with no ventilation will shorten its working life regardless of how much space it has. I build in ventilation, whether a discreet vented back panel, a gap behind a slatted door, or a small extract path to the room, matched to the depth and the equipment actually going inside.

Cable routing deserves the same forethought as ventilation — a rear cut-out or a routed channel lets cables run from equipment to a wall socket without being pinched against the back panel, which both looks neater and avoids strain on cable connectors over time.

Where a chimney breast is genuinely too shallow for the storage a client needs, projecting the base cabinets 50–100mm forward of the breast face is a standard and entirely deliberate solution rather than a compromise. Capped with a well-finished top and returned neatly at the ends, the step reads as intentional architecture rather than an oversized box bolted onto the wall. Beyond about 100mm of projection the balance shifts and the unit starts to feel like standalone furniture rather than fitted joinery, which is the point at which I would usually suggest reconsidering the layout instead.

This approach is especially useful for AV cabinets, where the equipment depth requirement is fixed and non-negotiable, while the shelving above can stay flush with the original chimney breast face to keep the upper part of the composition feeling lighter.

In a genuinely small room — a compact hallway, a box room, a narrow reception room — the instinct to maximise cabinet depth for maximum storage can backfire badly. A deep, dark unit running full height across a small alcove is felt as much as it is seen, and it can make an already tight room feel noticeably smaller. In these cases I often argue for the opposite approach: shallower cabinets, lighter paint colours, and open shelving in the upper zone rather than closed cupboards throughout.

The right question in a small room is not "how much can we fit in" but "how much storage can we fit in without the room feeling smaller for it" — and the answer is very often a shallower, better organised unit rather than the deepest one that will physically fit.

The most frequent depth mistake is a single depth figure applied uniformly across the whole unit regardless of what each section will actually hold — books, AV equipment and display objects all squeezed into cabinets sized for a generic "storage" brief rather than their specific contents. The second is measuring the alcove once, at one height, and missing a taper or bow that only shows up when the finished cabinet is offered up on installation day.

The third, and the one with the most lasting consequence, is ignoring sockets, pipes and skirting until after the design is finalised — problems that are trivial to resolve at survey stage become expensive and disruptive once the joinery has already been built to the wrong dimension.

Depth is one of the few dimensions in a joinery project that is genuinely difficult to change after manufacture, so it is worth the extra ten minutes at survey to talk through exactly what will go in each section before a single measurement is finalised. I always ask clients to bring along the actual items — a favourite oversized book, the specific AV equipment, a sample of what will be stored — rather than guessing from memory, since real objects settle depth arguments far faster than a description of them.

Where a client is torn between a shallower, lighter-feeling unit and a deeper one with more capacity, I would rather talk it through properly at the design stage than let indecision carry through into the build — a mocked-up cardboard template held against the wall, even a rough one, often resolves the question in seconds where a drawing alone could not.