Height measurement is to top or bottom of ceiling joist?

[Mrmatt]

A very simple question that I cannot seem to find a simple answer to, searching the code
and the forums:

The code says that I can install my rafter ties to a maximum 1/3 of the distance
from the supporting walls to the ridge board (IRC802.3.1), but what I can't find out
is, am I measuring from the supporting wall to the bottom of the rafter tie or the
top of the rafter tie?

Thanks in advanced all!

 

[fatboy]

Top of ties

 

[cda]

Welcome!!!

 

[SCBO1]

Minimum 2x4 and follow the nailing requirement, as an inspector I have no way
to determine if your measuring from the top or the bottom of the tie. Most of
the time I can't see the ties nailing unless I'm in the attic with the required attic
light when verifying there's insulation in the attic at final. For what its worth,
the WFCM only has "located in lower third of attic space".

*See IRC Table R802.5.1 (9) for required nailing, foot note f. Ya.. all of us
are enforcing this nailing chart.

 

[Buelligan]

My interpretation is that the tie must be within the lower third. Therefore, if measured to the bottom, then the entire tie is above the lower third. So divide the roof into 3 equal heights and keep the entire tie within the lower third. As shown in the post by fatboy. above.

 

[ADAguy]

The intent is for the height of your ceiling to not be less than the minimum allowed.