Bunk beds for low and sloped ceilings
On a slope, the measurement that matters is the lowest ceiling above the place the child sits and climbs. A shorty bunk is a lower, often shorter frame. If the low side is still tight, two ordinary beds are the safer layout.
Take three heights
On a straight ceiling one measurement is enough. On a slope, take the height at the tall wall, the height at the low side of the mattress, and the distance from the tall wall to where the slope starts to cut across the bed. The child sits and rolls across that whole rectangle. The lowest of those points is the one to plan with.
Boori’s guide says a sloped ceiling can change the usable height by several centimetres across the same wall, and tells you not to measure only the centre of a loft conversion. Beams, a dormer cheek and a boxed-in pipe do the same job as a slope: they are the ceiling, for this purpose.
What a shorty changes
Boori describes a shorty as a lower frame, often 20–30 cm lower overall, commonly with a mattress around 75 × 175 cm rather than 90 × 190 cm. They put a typical shorty top surface around 120–130 cm, against 145–155 cm for a standard bunk. With their 75 cm guideline, that is a ceiling around 2.0–2.05 m at the sitting position, against about 2.3 m for a standard bunk.
Those are Boori’s typical ranges, not a promise about every bed sold as a shorty. Ask for the frame height and the mattress size before you buy. A 75 × 175 cm mattress is also not the same as the 75 × 190 cm small single in Which?’s size table, so bedding is a separate check.
When to stop stacking
If the low side of the slope is already under the frame-plus-mattress-plus-75 cm sum, a shorter bunk will not fix it. Two low singles, or a cabin whose sleeping surface stays under the tall part of the ceiling only, are the layouts that do not ask a child to sit into the plaster.
A lower bed is not automatically outside the safety standard. BSI’s scope for BS EN 747-1:2024 is a bed base 600 mm or more above the floor. Many mid sleepers and high sleepers are in that scope. A very low play bed may not be. Read the mark on the one you buy.
Questions people ask
Can I put the pillow at the tall end and ignore the low side?
Only if the child never sits or climbs at the low side. Measure the lowest point they will actually use, including the ladder end.
Is a shorty a different safety product?
No. Boori says a shorty should meet the same expectations as a standard bunk, including guard rails and the right mattress height. Their own series guidance is a top bunk from age 9, which is stricter than the under-six warning on the standard.
Sources
Opened 13 November 2026. The maker’s sheet and the mark on the bed take precedence.