Conventional Roof bracing

[jsommerfeld (Justin Sommerfeld)]

@escanlan

First off the purlin is the horizontal member that is actually contacting the rafters. Strongbacks come in many forms and uses so it is best just to refer to a purlin as a purlin. Purlins are then supported by a “brace” that is run from purlin to a load bearing component (wall or beam) below it.

If I understand your question correctly you are asking about the spacing of the braces. Braces should be spaced no more than 4’ on center (OC). They do not have to be at the very end of the purlin but that is typical. Also braces should not be less than a 45 Degree angle from the horizontal framing below. Braces that are in excess of 8’ long must also be braced themselves typically by “T”'ing a piece of wood to it. That bracing helps prevent them from flexing.

So in your case 8’ OC braces are incorrect and should be called out. However the Inspector should also look to see if the incorrect placement is causing any issues and report either way. Since we do not know the intention of the original roof framing design, we don’t typically know the exact species of wood used for the rafters, unless the rafter spans are obviously extremely long then the purlins might not have originally been needed and may only have placed there by a conscientious framer who likes to make sure nothing would happen in the future.

Pics are sideways but here is the bracing