Hello, I'm wondering if someone can tell me if a home inspector should know attic rafter spans. We have a stick built attic with 2 x 6 attic rafters which hold up the roof. Every contractor tells us the rafters need to be 2 x 8 to carry the load of the roof. Even the center ridge beam is 2 x 6.

In addition the floor plan below ie: the ceiling of the rooms is an open floor plan with rooms as big as 16 feet. We are being told by contractors that the beams which hold up the ceiling needs to be at least 2 x 8 because the span underneath is 16 feet.

Should a home inspector who walked the attic know to look for span issues?
Thank you for your help.

[Sean Fogarty]

The home inspector does not measure and evaluate loads or spans when inspecting. I personaly make a note if I notice an obvious issue or problem, but to many factors exist to make that call. When was the home built? Where is the home?
The structure does not need to be as strong when no load is expected. Your question can only be answered by an engeneering examination, not by a contractor. The house should have been designed with blueprints and all those factors were calculated when the plans were drawn up.
Also most standard maufatured trusses are 2x4's so that kind of shoots down the idea of 2x6's not being strong enough in some repsects. Rafters are capable of spanning a certain length depending on the size, the bigger they are the longer they can span.
I would say if the home is no more than 50 years and everything looks satisfactory then there should be no problem. If you are concerned additional bracing can always be added, but you can't blame the inspector for not doing somthing they are not required to do.

[Mario A. Kyriacou, CHI]

Many items have to be taken into consideration including loads, roof pitch etc. Dwarf walls, collar ties etc. are also used to construct roofs. I don't know the area in which you reside but It sounds to me that you are at the limit of allowable span. Can you provide additional information? Type of roof, snow load etc.
BTW It has been my experience that contractors know current code.