That depends entirely on the physical characteristics and construction of the lumber. There is simply no way of answering this question without more info. A two-by-four (2x4) will support more weight than a similarly loaded one-by-three (1x3). A 2x4 will support a greater load on its two-inch face than on its four-inch face.
4.5 kgDepends
Without knowing how the roof was constructed and with what dimension of lumber or steel, there is no way to estimate.
49 pounds
it can't hold very much weight
See if they have a weight limit and know about how much your funrniture weighs. You will want to be sure they are metal in most case to hold the weight.
About as long as a piece of string
19 5/8 inches
20 times its weight in liquid
112lbs
it can hold as much weight as it can handle
How much a surgery on lumber L4 L5
There is effectively no limit to the amount of weight that aluminum can hold, if you use enough aluminum.