The phenomenon of a metal ball in the neighbors upstairs

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

The rolling ball phenomenon is a phenomenon that usually occurs in panel houses, much less often in brick houses. The victim of this phenomenon wakes up in the middle of the night from the sound of an iron ball rolling (or falling to the floor and shallowly bouncing) on the floor above.

This effect is especially noticeable in houses made of reinforced concrete slabs, as well as other materials with air voids. During the day, when the ambient temperature is higher, the structure heats up. In the evening and at night, when the temperature drops, the materials give off heat, and voids give rise to a sound effect reminiscent of a rolling ball. This explains the fact that these sounds are usually heard at night.

People who are not burdened with reason believe that these sounds are the sounds of all falling things and children's toys from the neighbors above. True, it is difficult to imagine a child playing with a large ball bearing at night.

But in addition to the slab, there is also a floor covering, which consists of linoleum, a substrate for a laminate and other sound insulators.

The most likely explanation (at least the most consistent) is the version about the thermal stress in the reinforcement of reinforced concrete structures, in particular, floors, one of the subspecies of which is given in the quote above. The bottom line is this: during the day, building structures heat up and deform due to thermal expansion. Stresses arise in the reinforcing cage of the slabs (roughly speaking, the reinforcing rods bend or shrink quite a bit). This is not a problem for the strength of the building; moreover, these deformations are provided for by the project. At night, the temperature of the outside air, and, consequently, of the concrete structures, drops, and at a certain moment the reinforcement relaxes (the same "ball fall"), followed by an oscillatory return of the reinforcement to its original position (and now the "ball rolls"). The propagation of sound is helped, firstly, by the material of the structures itself (reinforced concrete conducts sound very well, any resident of a panel house will confirm this to you), and secondly, the abundance of voids both in the slabs and in the building itself, which generates acoustic resonance. To illustrate, guitarists and bassists can slightly tug the string on their instrument, and housewives can listen to sounds from a cooling iron or stove (a loud click of a stove is the crackling of the burner itself, and not the mechanism in the stove, yes, yes) or pour a bucket of hot water into the kitchen stainless steel sink instead of porcelain.

Why is the sound heard from the ceiling? Yes, because, firstly, the floor usually has at least some kind of coating (linoleum, chipboard) that absorbs noise, and, secondly, relative to the room (and the owner of this room), the ceiling is something like a membrane or "sound mirrors ", which reflects sound from the floor and walls. This version is supported, firstly, by the strength of materials and other construction sciences, beloved by all students, and, secondly, by the fact that the phenomenon is most pronounced when the gradient between day and night temperatures is maximum.

This version is especially relevant for houses with wooden floors, because wood also "breathes" along with changes in temperature, as a result of which the rafters hum. In such houses, the sounds, as a rule, are even more bricked - not only rolling balls, but also creaks, steps, sighs and other joys of "haunted houses".

I read the topic - ofigel. The same bullshit. Stably at 2: 30-4: 30 something falls from the neighbors from above like a ball and rolls bouncing … really almost every night!

I live in a 5-storey building, without elevators, etc., sometimes at night, and maybe during the day, something like this rolls somewhere from above, if we assume that this is a ball from a bearing, then the diameter of the ball there is probably 20 centimeters. I don’t think that neighbors drive to bowling at 4 o'clock in the morning, and I didn’t notice such balls.

For statistics

- 17-storey panel house (70s), Moscow. Neighbors, once or twice every 1-2 weeks, began to move furniture after a metal object (presumably a large metal ball) fell on the floor (and was hit several times);

- 2-storey fully wooden house (late 60s, early 80s), NZ. A metal ball is rolled from one side of the ceiling to the other. Once a night. Once every 1-2 weeks.