How to Measure Up for Alcove Shelving: A Simple Sizing Guide

To measure an alcove for shelving, take the width at three heights (near the floor, at waist height and near the top), the depth at the same three points, and the height from floor to ceiling or to any picture rail. Use the smallest width and the smallest depth as your working figures, then subtract a clearance of around 1cm to 2cm on each side so a freestanding unit can slide in without scraping the walls. Check for skirting boards, sockets and radiators before you settle on a size.

That is the short version. The rest of this guide explains each step in more detail, because alcoves in British homes are rarely as straightforward as they look. Once you have your figures, you can compare them with the dimensions in our range of shelving units UK sale to find designs that fit.

What You Will Need

• A steel tape measure, ideally at least 3 metres long
• A pencil and notepad, or a phone to record figures
• A spirit level
• A second person, if possible, to hold the other end of the tape

A laser measure is helpful for heights but not essential. Measure in centimetres throughout so you can compare your figures directly with product listings.

Step One: Measure the Width at Three Heights

Walls in older houses are often out of square, and chimney breasts can be slightly tapered. Measuring the width once is not enough.

1. Measure across the alcove just above the skirting board.
2. Measure again at around waist height.
3. Measure a third time near the top of the space where the unit will reach.

Write down all three. The smallest figure is the one that matters, because the unit must pass through the narrowest point. It is common to find a difference of a centimetre or more between the top and bottom of an alcove in a Victorian or Edwardian home.

Step Two: Measure the Depth at Three Points

Depth is measured from the back wall of the alcove to the front face of the chimney breast. Again, take readings near the floor, in the middle and at the top. Chimney breasts sometimes step in or out, so check carefully.

You do not have to fill the full depth. Many people prefer a unit that sits slightly back from the face of the chimney breast, so the breast remains the strongest architectural feature. Others prefer the front of the unit to line up flush. Decide which look you prefer before choosing.

Step Three: Measure the Height

Measure from the floor to the ceiling, then to any picture rail and to the underside of any cornicing. If you would like the shelving to stop at a particular line, such as the mantelpiece or the top of the window, measure that too.

Check the floor with a spirit level. Uneven floors are common in older homes, and a slope across the alcove will affect how the unit sits. Units with adjustable feet are useful here.

Step Four: Note the Obstacles

Alcoves often contain things that interrupt a clean fit. Make a note of:

• Skirting boards. Measure their height and depth. A deep skirting pushes a freestanding unit forward unless the unit has a cut out at the back or sits above it.
• Picture rails and dado rails. These also project from the wall and can prevent a tall unit sitting flush.
• Sockets and switches. Mark their height and distance from the corner. You may want to keep them accessible.
• Radiators and pipes. Shelving should not sit directly in front of a radiator, both for heating efficiency and to protect the furniture.
• Window reveals and door frames. If the alcove sits beside a window, check the depth of the reveal and any shutters.

Step Five: Allow for Clearance

A freestanding unit needs a little room to manoeuvre. As a guide, deduct around 1cm to 2cm from each side of your smallest width measurement. So, if the narrowest point of your alcove is 92cm, look for a unit of around 88cm to 90cm wide.

Remember that the unit may need to be tilted upright once assembled. Measure the diagonal of any tall unit you are considering and check it is less than the ceiling height, or it may not stand up in the room. This is a common issue with tall units in rooms with lower ceilings.

Recording Your Measurements

A simple sketch is very useful. Draw the alcove as a rectangle, mark each measurement in place and add notes about obstacles. Take a photograph of the alcove as well, so you can refer back to it while browsing. If you have two alcoves, label them left and right, as their sizes often differ.

Choosing the Right Unit for Your Measurements

With your figures recorded, you can start to narrow down options. Our wider collection of modern living room furniture UK shows how shelving relates to other pieces in the room, and it is worth considering the alcove in that broader context.

Tall or low?

Tall units maximise storage and suit rooms with high ceilings. Low units, stopping at mantelpiece height, leave room above for artwork or a mirror and keep the room feeling open. For a large book collection, deeper and taller modern bookcases UK sale may give you more usable shelf space than a general shelving unit.

Open or display focused?

If the alcove will mainly hold decorative objects rather than books, a lighter, more open design may suit better. Our display stands and units UK are designed with this kind of styling in mind.

Matching or different?

A matching pair either side of a chimney breast creates symmetry. If the two alcoves are different widths, choose units of the same style and height. The eye notices height and style far more than slight differences in width.

Getting Shelf Spacing Right

The outer dimensions are only half the story. Shelf spacing determines what you can actually store. Paperbacks need a gap of around 22cm to 25cm, hardbacks around 30cm, and larger art books or vinyl records around 35cm. Adjustable shelves offer the most flexibility.

For more detailed guidance on internal dimensions, our article on shelf spacing, heights and depths for UK storage is a useful reference.

Alcoves Beside a Media Wall or Fireplace

Many people use alcove shelving alongside a television or fireplace on the chimney breast. If you plan to do this, think about how the two will work together visually. Keep the shelving height consistent with the top of the fireplace or television so the wall feels balanced, and leave space for cables if equipment will sit on the shelves. Our guide to fitting a TV unit with fireplace in a small UK room includes helpful advice on balancing this wall.

Common Measuring Mistakes

• Measuring the width only once, rather than at several heights.
• Forgetting to allow for skirting boards and picture rails.
• Ignoring the diagonal height needed to stand a tall unit upright.
• Assuming both alcoves are the same size.
• Not checking the route into the room, including stairs and doorways.

Checking the Route Into the Room

An alcove unit that fits the space perfectly is no use if it cannot reach the room. Before ordering, measure the width of the front door, any internal doors on the way and the narrowest point of the staircase if the room is upstairs. Pay special attention to turns on the stairs and the space at the top of the landing, as these are where large items most often become stuck.

If a unit is delivered flat packed, the boxes are usually easier to carry than an assembled piece. Even so, the longest panel needs to travel through every turn, so check the box dimensions as well as the assembled size.

Creating a Fitted Look With Freestanding Shelving

Many people want the look of bespoke alcove joinery without the cost and disruption of a carpenter. A freestanding unit can come surprisingly close if a few details are right. Choose a width that leaves only a small, even gap on each side. Paint the alcove walls the same colour as the unit, or a close shade, so the gaps disappear visually. Keep the top of the unit level with a clear architectural line, such as the mantelpiece or picture rail.

Styling also plays a part. Shelves that are styled consistently across both alcoves, with similar spacing and a repeated palette of objects, read as a single deliberate scheme rather than two separate pieces of furniture.

Securing the Unit

Once your shelving is in place, fix it to the wall with the supplied anti tip fittings. In an alcove, you can often fix into the back wall or the side of the chimney breast. Check the wall type first: brick, plasterboard and lath and plaster each need different fixings.

When you have your measurements ready, you can browse our full range of modern furniture at Furniture in Fashion, with free delivery to most UK mainland postcodes.

Frequently Asked Questions

How much gap should I leave either side of an alcove unit?

Around 1cm to 2cm on each side is usually enough to slide a freestanding unit into place without scraping the walls. Measure at several heights and use the narrowest figure.

How deep should alcove shelving be?

It depends on what you store and how far the chimney breast projects. Around 25cm to 35cm suits most books and objects. Many people prefer the unit to sit slightly back from the front of the chimney breast.

What if my alcoves are different sizes?

Choose units of the same style and height. Small differences in width are rarely noticeable once the shelves are styled.

Do I need to remove the skirting board for alcove shelving?

Not usually. Many freestanding units sit just in front of the skirting, or you can choose a design that clears it. Factor the skirting depth into your measurements before you choose.