Rafter Fracture - determining the age of the fracture

[PSUengineer1]

I observed tensions fractures in a rafter (residential) that are aged in appearance as the color of the wood at the interior of the fractures is not clean and distinct relative to the color of the wood at the rafter’s exterior. The disoloration of the interior surface of the cracks is an indication that the cracks are weathered and oxidized. I am trying to "date" the fractures. I have been tasked to determine if the fractures occurred within the past 2 years. I have no known event within the past approximate 2 years to date the fractures to. I understand that factors such as wood species and attic ventilation would play into the rate at which the fractured wood would oxidize but I opine that ultimately it comes down to engineering judgement. Anyone out there have some tips as to determining the age of a fracture? If so, please share.
Thanks.

 

[racookpe1978]

How old is the "outside" of the rest of the wood nearby? (Or is that what the "two years" comes from? )

Can you find splinters or non-vital cracks to show what a "fresh crack" wood interior looks like?

 

[jfmann]

Only realistic "method" would be to have some reliable history, especially photos....but of course who would have taken photos in attic, right?

I dated a fracture once.........oh no, let's not

Has there been heavy snow load in past 20 years?..........anyone working on roof?.........of course could have been damaged during construction (happenes frequently)



John F Mann, PE

http://www.structural101.com

 

[MotorCity]

Just a side note.....if the client is asking you to determine if this fracture occurred within the last 2 years (a very specific time frame), you may want to ask him/her a few more questions regarding the nature of this request.

Smells like a lawsuit could be brewing. Perhaps they are trying to build a case for other damages that may have occurred as a result of this fracture. You may be their "expert witness" without even knowing it if you were to provide a definite cause in writing. Be careful.

 

[chicopee]

I would think that the discoloration of the interior of the crack would have a lighter appearance than the exterior surface of the rafters. Is that so?

 

[chicopee]

About providing pictures of the entire crack; also is it possible that the crack occurred in a damage section of the rafter?