Not all slat platform beds are created equal. The ideal weight capacity will depend upon the type of wood used for the slats, the thickness of the wood, the number of slats and the overall construction of the frame. Some slat bed manufacturers will include a weight capacity on the label; however, when viewing the weight capacity, you must remember to include the weight of the mattress. Thus, for example, if the weight capacity reads "400 pounds," you must first subtract the weight of the mattress to determine how much human weight the slat bed can handle.
While some slat beds may be advertised as having a high weight capacity, this capacity typically accounts only for even weight distribution. Individual slats are highly sensitive and can break easily with excess weight. If an overweight person kneels on one of the slats or bends in a way that places too much pressure on one slat, it may break. This fact alone may cause some overweight people to reconsider purchasing a slat platform bed.
Slat beds naturally place a lot of strain on a mattress due to the way the slats are spaced from one another. The gaps between the slats place uneven pressure on the mattress, causing it to wear out much sooner than it would on a more conventional box spring surface. This pressure is only heightened with the increased mass of an overweight person.
Slats have a tendency to sink when weight is applied. This can result in diminished back support, incessant squeaking noises and even spinal injury over time. While a lightweight person will not cause the slats to sink very much, an overweight person can cause the problem to occur more dramatically.
If you have a large frame, a box spring support can typically offer you the greatest level of comfort and support, with the smallest potential for injury. However, if you want to obtain the benefits of a slat platform bed, do your research and find one designated to handle a lot of weight.