Bunk Bed Buying Guide: Frames, Heights and Mattress Sizes

Choosing a bunk bed comes down to three measurements and one material decision. You need to know the ceiling height of the room, the overall height of the frame, and the mattress size and depth the frame is designed for. Then you choose between timber and metal construction based on how the bed will be used. Get those four things right and almost every other detail, from ladder position to storage, falls into place.

This guide walks through each decision in the order we would make it ourselves when planning a shared bedroom. If you already have a shortlist from our bunk beds UK sale range, use the sections below to check each frame against your room before committing.

Start With the Room, Not the Bed

It is tempting to begin with styles and colours, but the room sets the limits. Before looking at any frame, take three measurements: the floor length and width available for the bed, the ceiling height at the exact spot the bed will stand, and the distance to any window, radiator, wall light or door swing nearby.

Ceiling height matters most. A child on the top bunk needs enough clearance to sit up, turn over and climb in without knocking their head. Measure from the floor to the lowest point of the ceiling above the bed position, including any beams, sloping eaves or a low pendant light. In many modern UK homes ceilings are lower than in Victorian and Edwardian properties, and loft conversions often slope sharply.

A sensible rule is to subtract the overall frame height and the mattress depth from your ceiling height. What remains is the headroom on the top bunk. If that figure would leave a child unable to sit upright comfortably, look for a lower frame or choose a different spot in the room.

Understanding Bunk Bed Frame Types

Bunk beds have broadened well beyond the classic two singles stacked one above the other. Knowing the main types helps you match the frame to the household.

Standard bunk beds

Two single beds stacked vertically with a fixed ladder. This is the simplest and usually the most compact footprint.

Split or detachable bunks

Two single frames that stack together but can be separated later into two standalone beds. These are useful when children may eventually move into separate rooms.

Triple sleepers

A small double or double bed on the bottom with a single on top. They suit families who host sleepovers, or households where an older child or adult may use the lower bed.

Mid sleepers and low bunks

Lower overall frames designed for younger children or rooms with limited ceiling height. The top bunk sits closer to the floor, which also makes it less intimidating for a first climber.

Bunks with storage or trundles

Frames that include drawers beneath the bottom bunk, shelving in the end panels, a staircase with drawers built into the steps, or a pull out trundle bed for a third sleeper.

Frame Materials and What They Mean Day to Day

Timber frames, particularly solid pine and hardwoods such as oak or rubberwood, feel warm and substantial. They tend to be quieter when children climb or move during the night. Solid wood can be sanded and refinished if it is marked, which suits a bed that may be used for many years.

Engineered wood such as MDF is often used for panels, headboards and storage drawers. It gives a smooth painted finish and helps keep frames affordable, but it is less forgiving if it gets wet or chipped. Look for solid timber in the structural uprights and rails, with engineered panels used only where they do not carry much load.

Metal frames are slim, light and strong for their size. They take up less visual space, which helps in a small room. Powder coated finishes are easy to wipe clean. The trade off is that metal can creak or squeak if fixings loosen, so retightening bolts periodically is worthwhile.

Whichever you pick, it should sit comfortably with the rest of the room. Browsing our wider bedroom furniture UK collection can help you match wardrobes and chests to the frame material you choose.

Heights Explained

Three height measurements appear in most bunk bed descriptions, and each serves a different purpose.

Overall height is the distance from the floor to the very top of the frame, usually the top of the guard rail or the upright posts. Use this against your ceiling measurement.

Top bunk base height is the distance from the floor to the slats of the upper bed. Add your mattress depth to this to find where the sleeper actually lies.

Under bunk clearance is the space between the bottom mattress and the underside of the top bunk. This determines whether someone on the lower bed can sit up to read, which is worth checking if an older child or adult will sleep below.

For a shared room with younger children, a lower overall height is often more comfortable and less daunting. Teenagers and taller sleepers generally appreciate more headroom on both levels.

Mattress Sizes and Depths

Most bunk beds in the UK are built around a standard single mattress measuring 90cm by 190cm. Some compact frames use a small single at 75cm by 190cm, and triple sleepers usually take a small double at 120cm by 190cm or a standard double at 135cm by 190cm on the lower level. Always confirm the exact size in the product details, because a mattress that is too small leaves gaps that small hands and feet can slip into.

Depth is just as important on the top bunk. Guard rails are designed with a specific mattress depth in mind, and the manufacturer will normally state a maximum. A deeper mattress raises the sleeper and reduces the height of the rail above them. Many families choose a slimmer mattress for the top and a slightly deeper one for the bottom, where there is no rail concern.

Comfort still counts. Open coil, pocket sprung, foam and hybrid mattresses are all available in bunk friendly depths. Our modern mattresses UK range lets you filter by size, which makes it easier to find a suitable depth for each level.

Ladders, Rails and Safety Standards

Bunk beds sold for domestic use in the UK should meet BS EN 747, the standard covering bunk beds and high beds. It sets requirements for guard rail height, gaps between parts, ladder design and structural strength. Ask about compliance if it is not stated clearly.

Ladders come in two main styles. Vertical ladders save floor space but are harder for young children to climb. Angled ladders and staircases are easier and safer to use, particularly at night, but extend the footprint of the bed. Staircases with storage drawers built into the steps combine both access and storage.

The guard rail should run along both long sides of the top bunk, or along the open side if the bed is placed against a wall with a wall side rail too. It is widely recommended that children under six do not use the top bunk.

Planning Around Younger Children

If your youngest is still small, think about how the bed will work in the years before they are ready for the top bunk. A low frame or a split design gives you options. Some parents start with the beds separated as two singles and stack them later. Others choose a mid sleeper first and move to a full bunk when the children are older. Our children’s beds UK sale collection includes lower options for this stage.

Final Checks Before You Order

Run through a short list before you buy. Confirm the overall height leaves comfortable headroom. Check the footprint, including the ladder or staircase, fits the floor space. Make sure the mattress size and maximum depth suit what you plan to use. Look at assembly requirements, since bunk beds usually arrive flat packed and are easier to build with two people. And measure stairways and landings if the room is on an upper floor.

For a deeper look at how room proportions affect furniture choices, our article on ceiling heights in UK homes by property age is a useful reference when you are measuring. And if comfort is your main concern, our piece on mattress firmness for UK sleepers explains how firmness labels compare in practice.

When you are ready to compare frames, you can browse the full bedroom range at Furniture in Fashion, where we offer free delivery to most UK mainland postcodes.

Frequently Asked Questions

How much ceiling clearance does a top bunk need?

Enough for the sleeper to sit upright without touching the ceiling. Subtract the overall frame height and mattress depth from the ceiling height at the bed position, then check whether the remaining space suits the child using the top bunk.

What size mattress fits a standard bunk bed?

Most standard bunk beds take a UK single mattress measuring 90cm by 190cm. Compact designs may take a small single, and triple sleepers take a small double or double below. Always check the frame details.

Can I use any mattress depth on the top bunk?

No. Use a mattress no deeper than the maximum stated by the manufacturer, so the guard rail remains effective.

Are metal or wooden bunk beds better?

Both can be excellent. Wooden frames feel solid and quiet, while metal frames are slim and space efficient. Choose based on your room size, style and how much movement the bed will see.

At what age can a child sleep on the top bunk?

It is widely recommended that children under six do not sleep on the top bunk. Consider the individual child’s confidence and coordination as well.