Buying a trundle bed for a children’s room seems simple until the moment comes to pull out the second mattress and you discover that it doesn’t fit, that the opening rubs against the wardrobe, or that the bed base is so heavy that the child can’t open it alone. Here are the most common mistakes, with concrete solutions.
1. Measuring only the closed bed and forgetting the opening space
The number one mistake. A trundle bed needs a clear front to pull out the lower module: between 70 and 90 cm depending on the system (wheels, rails or drawer). If the bed is pushed against the window wall or right in front of the wardrobe, the trundle becomes unusable. Solution: draw the full rectangle on the floor with masking tape with the bed open, not with the bed closed. And check that the bedroom door opens without bumping into it.
2. Ignoring the weight of the top mattress
Many trundle beds are sold without a mattress and the user buys two identical ones. But the mattress on the upper level bears the weight of a child who jumps, and the trundle one is only used occasionally. A cheap spring mattress on top deforms within months. In practice, it’s worth investing in the top mattress (high-density foam or pocket springs) and choosing a thinner, firmer one for the trundle, with a maximum thickness of 15-18 cm, because thick models prevent the set from closing.
3. Choosing a pull-out system that the child can’t handle
There are three common systems: wheels, metal rails and a drawer with a handle. Wheels are the cheapest but they misalign with use and scratch the floor; rails are more stable but require the bed to be perfectly level; the drawer with a handle is the most comfortable for a child aged 6-8, although it weighs more. Practical tip: if the child is under 6 years old, a trundle with wheels and a brake is safer than a drawer that can close on its own and trap fingers.
4. Not checking the height of the top mattress relative to the guardrail
In trundle beds with a safety guardrail, standard UNE-EN 747 specifies that the mattress must sit at least 16 cm below the top edge to prevent falls. Many low-cost models fail this point with thick mattresses. Solution: measure the distance between the mattress surface and the edge of the guardrail yourself before removing the packaging. If it’s less than 16 cm, return it.
5. Buying without checking the thickness of the trundle mattress
The trundle usually has a 90×190 cm space but with limited height. A 20 cm mattress doesn’t fit and forces you to leave the drawer half-open, which defeats its purpose. Manufacturers state the maximum height, but many buyers ignore it. Always check the technical specifications: mattresses of 15 cm or less are the safe option for the lower module.
6. Forgetting ventilation and dust under the bed
Closed trundle beds accumulate dust in the lower area and, if the child is allergic, it shows. A detail you only learn with use: models with a ventilated board base and legs raised 15-20 cm allow you to vacuum and reduce dust mites. Models with an airtight drawer are cleaner but heavier and don’t ventilate. There’s no perfect solution: choose according to priority.
7. Not planning for future use as a single bed
A trundle bed for a children’s room is used for only a few years. If the child grows and needs a fixed 90×190 bed, a model with a removable trundle allows you to separate the two beds and use the module as an auxiliary bed in another room. Models with a welded fixed trundle don’t allow this. According to manufacturers’ catalogues, detachable systems usually cost 15% to 25% more, but they extend the useful life.
What doesn’t work (and is worth knowing)
Trundle beds are not a good option if the child weighs more than 40-45 kg (the usual limit of the lower module) or if the room is less than 8 m², because the opening space eats up the walkway. Nor do they replace a bunk bed in rooms shared by two children who sleep there every night: the trundle is intended for occasional use. If the need is daily, a bunk bed is better.
Before buying, ask the seller for the technical specifications with open dimensions, maximum weight per level and maximum mattress height. If they don’t provide it, that’s a warning sign.