The structure is "sagging" the floor joists have been installed the wrong way lousy construction practice poor design
If your house is wood framed with wood joists, the shaking may be caused by floor joists being too small. This will cause the floor to sink whenever a person walks across the room. Floor joists should be size by an experienced carpenter, architect, or engineer to prevent movement.Another cause of floor movement may be insufficient bracing between the floor joists. This will cause sagging and twisting of the joists.There are several solutions that require the skills carpenter. New joists can be added beside the existing joists to strengthen the floor. Another option is to add one or more beams and columns in the room below the floor. Or blocking can be added between existing joists to add support.
It can be caused by GRAVITY as in the case of old lead pipe sagging. In addition copper contact wires in electrified transport systems sagging under permanent stress causes creep.
Being very overweight would cause sagging, but it's hard to tell without seeing you or knowing your height and weight.
It can be caused by GRAVITY as in the case of old lead pipe sagging. In addition copper contact wires in electrified transport systems sagging under permanent stress causes creep.
Sagging bending moment causes the beam to bend in a way to make concavity downward (cup-shaped) and it results in developing tensile stress in lower half of the beam x-section.
Yes. Rafters and flloor joists do not have to run the same direction.
Sagging pants? US prisons.
Joists resting upon sills and girders
That depends upon the size of the joists & grade/species of wood
Different situations call for different joists. Generally floor joists are 2 x 12.
Different manufacturers. Trusjoist McMillan (sp?) and Boise Cascade