290. Not Davening in an Elevated Location

Tefillah u’Birkas Kohanim 5:7

One should not daven while standing somewhere three handbreadths (about 10 inches) or higher. This would include a bed, a bench and a chair. If a raised platform has a surface area of four cubits by four cubits (approximately 72” x 72”), this is the smallest size of a house, so it is considered like an attic and one is permitted to daven on it. Even if it is not four cubits by four cubits, if it is surrounded by walls, one may daven there. This is because it now constitutes its own domain and its height is immaterial.

Tefillah u’Birkas Kohanim 5:8

Workmen who are laboring in the top of a tree or on a wall when the time to daven arrives must descend in order to daven, after which they return to their work. If they were on an olive tree or a fig tree, they may daven where they are because climbing down involves a tremendous amount of effort. If they work just for meals, they recite a normal, full-length Shemoneh Esrei. If they work for wages, they recite the abbreviated Shemoneh Esrei (refer back to 2:3). In either event, they do not repeat Shemoneh Esrei or recite birkas kohanim (the priestly blessing).