A correctly assembled cot that passes all pre-use safety checks is the single most important thing UK parents can do before placing a baby in their sleep space for the first time. A proper cot safety check confirms that the frame is correctly assembled, the mattress fits snugly, all fixings are tight, slat spacing meets BS EN 716 guidance and the rail height suits the baby's developmental stage.
Most cot assembly problems are discovered at the worst possible time, often late at night when the baby needs to sleep. This guide explains what to check before assembly, the most common UK cot setup mistakes, the post-assembly safety checks and when to lower the cot base.
Pre-Assembly Checks
Before starting cot assembly, lay every component on the floor and check it against the parts list. This simple step prevents one of the most common frustrations: discovering a missing bolt, cam lock or panel halfway through assembly. It is much easier to contact the retailer before the frame is half-built.
Inspect every part before fitting anything together. Look for cracks in timber panels, bent metal parts, damaged cam lock fittings, missing slats or any piece that looks warped from transit. Do not assemble a damaged cot and "see how it goes". A cot is a sleep space, so any structural doubt should be resolved before use.
Read the full manual before starting. Many cot assembly mistakes happen when parents follow diagrams quickly but miss written notes about slat direction, base height or model-specific fixings. Boori assembly manuals are available through the Boori website and should be followed for the exact model, not a similar-looking cot.
Assemble the cot inside the nursery where possible. Fully assembled cots often cannot fit through UK doorways, especially in terraced houses, flats and smaller box rooms. Clear enough space to lay panels flat, protect the floor, and keep all fixings in one tray so nothing disappears under furniture.
If you are still choosing the frame, start with browse all Boori cots before buying mattresses or accessories.
The Most Common UK Cot Assembly Mistakes
The first common mistake is choosing the wrong mattress base height. Newborns usually start with the base at the highest position because it allows easier lifting. The base should then move down as the baby develops. Parents sometimes wait too long, which can make climbing or pulling up more dangerous later.
The second mistake is overtightening cam locks and fixings. A cam lock should be turned until it clicks or tightens as the manual explains, not forced beyond that point. Overtightening can strip the fitting, weaken the joint and require the full part to be replaced.
The third mistake is incorrect slat orientation. Some cot slat systems are directional, so the slats must be fitted exactly as shown in the model diagram. If slats sit the wrong way, they may feel secure at first but work loose over time with mattress movement and regular use.
The fourth mistake is skipping the final stability test. Once the cot is built, apply gentle pressure to each side, rail and corner. There should be no wobble at any joint. Any movement means a fixing needs to be identified and tightened before the cot is used.
If you find a missing or damaged fitting, use replacement fixings for Boori cots rather than guessing with third-party hardware.
Post-Assembly Safety Checklist: BS EN 716 Requirements
After assembly, the cot should be checked against BS EN 716 safety points before the baby sleeps in it. Start with slat spacing. No gap between cot slats should exceed 45mm. Measure several gaps, not only one, because a single slat fitted incorrectly can create a wider opening than expected.
Next, check mattress fit. The mattress should sit snugly inside the frame, with no gap exceeding 25mm between the mattress and any side or end. Press the mattress into each corner and check all edges. If the gap is too large, the mattress is not the right size for that cot.
Rail height is another essential check. BS EN 716 requires the cot rail to be at least 500mm above the mattress at the highest base position and at least 200mm above the mattress at the lowest base position. This is why mattress thickness and base height must be checked together.
Finally, run your hand along every external edge at child-contact height. There should be no sharp edge, splinter, protruding screw or rough join. The Lullaby Trust also recommends a firm, flat, well-fitting mattress for safer sleep, so the frame and mattress should be treated as one setup.
You can find the right cot mattress if the mattress supplied or reused does not fit the frame correctly.
When to Lower the Base and When to Move On?
The cot base should be lowered before each new movement stage becomes risky. Move to the middle position when your baby can sit up unassisted, which is often around 5--6 months. Do not wait until they are already pulling themselves upright, because the change should happen before the risk increases.
Move to the lowest position before your baby can pull to standing, often around 7--9 months. A baby who can pull up while the base is still at mid-height may be able to lean over the rail further than expected. This is one of the main reasons regular cot safety checks matter.
The next stage comes when your child can climb out at the lowest base position, or when they reaches 90cm in height, whichever happens first. Do not wait for a fall before moving on. At that point, the cot is no longer the safest sleep space.
For Boori cot beds, this is usually when the cot bed conversion becomes useful. You can convert your Boori cot bed using the correct kit and model instructions, so the sleep space changes into a toddler setup instead of jumping straight to a full-size bed.
FAQ
What safety checks should I do on a new UK cot?
Check slat spacing, mattress fit, rail height, fixings and surfaces before the cot is used. Under BS EN 716 guidance, slat gaps should not exceed 45mm, mattress gaps should not exceed 25mm, and all joints should feel secure. Repeat these checks every 6 months.
When should I lower the cot mattress base?
Lower the cot mattress base to the middle position when your baby can sit up unassisted, usually around 5--6 months. Move it to the lowest position before your baby can pull to standing, often around 7--9 months. Do not wait until pulling up has already started.
What is BS EN 716?
BS EN 716 is the UK safety standard for children's cots. It covers important safety requirements such as slat spacing, mattress fit, rail height and structural safety. For parents, it gives a practical framework for checking whether a cot is assembled safely before use.
How do I know if my cot assembly is safe?
Apply gentle pressure to all sides, corners and rails after assembly, and make sure no joint moves. Then check slat spacing, mattress fit, rail height and all child-contact surfaces. If anything wobbles, catches, splinters or leaves a large gap, it must be fixed before use.
What are the most common UK cot assembly mistakes?
The most common UK cot assembly mistakes are setting the mattress base at the wrong height, overtightening cam locks, fitting slats in the wrong direction and skipping the final stability test. These mistakes can usually be avoided by reading the full manual before starting.
When should I move my baby out of the cot?
Move your baby out of the cot when they can climb out at the lowest base position, or when they reach 90cm in height, whichever comes first. For Boori cot beds, this is often the right time to convert the cot bed into toddler mode.
Summary
A safe cot passes every BS EN 716 check, uses the correct mattress, has the base set for the baby's current movement stage and is reassessed every 6 months. Before first use, check the frame, slats, mattress fit, rail height, fixings and surfaces calmly rather than relying on assembly alone. For Boori assembly support, spare hardware and cot bed conversion guidance, visit Boori's official support pages, browse all Boori cots, order replacement fixings for Boori cots, or check how to convert your Boori cot bed when your child is ready.
