That depends upon the size of the joists & grade/species of wood
It will hold up the human body if it is placed on it. Technically, the effect will be that it will hold the body off the subflooring and floor joists.
Better put them in. Something has to hold the roof or roof panels up and prevent them from holding water.
Try not to invite Aretha Franklin and Queen Latifah over for dinner and your floors should hold up just fine.
That depends on how well supported the floor is and that depends on how far apart the joists are placed. The closer they are, the more weight can be supported.
Generally, the horizontal members in a building are called beams. Beams can be girts, which hold up joists, headers, which are found above windows, plates, that hold up rafters, etc. Beams are usually structural members.
Any joists which are not straight shoud be positioned with the camber or crown (curved edge) upwards. When loaded these joists will tend to straighten out rather than sag further if laid the other way up!
You're going to have add columns supporting the bottom and top of the stringers.Or you can double up the joists on either side of the top and thru-bolt them to stringers.You'll have to double or triple up the joists below the stringers (depending on the span of the joists)
Some common structural members of a timber framed house include the timber posts or columns, timber beams, and timber joists. These components provide the framework and support for the structure. Other structural members may include timber studs, rafters, and wall plates.
Yes. Rafters and flloor joists do not have to run the same direction.
Joists resting upon sills and girders
Different situations call for different joists. Generally floor joists are 2 x 12.