Rafter self-supporting or not?

[Daveo]

Just as the title suggests, how can one tell from the construction of a truss if it is self-supporting or if it has support with a load-bearing wall in the middle?

 

[Snailman]

Have wondered the same thing a bit, but mostly when I'm going to order them (for new construction)

In the link below, I see it as being supported at S3 (i.e., non-load bearing)
http://www.takstolsfabriken.se/man_takstol.php

while the one below should be load-bearing

http://www.takstolsfabriken.se/fack_takstol.php

if the last one is available in a non-load-bearing variant, it should have smaller dimensions on the timber.

Otherwise, if you have existing trusses, you can perhaps input their dimensions into this program, http://www.martinsons.se/default.asp?id=13332&PTID=&refid=13339, and see what they 'can handle'

 

[anaitis]

In the following, I see it as having support at S3 (i.e., non-load-bearing)
[link]

Almost right: The support at S3 is not for holding the roof, but for having a floor structure, i.e., to be able to furnish the upper floor.