White growth on rafters

These rafters were found in the attic of a new modular home. I think they probably sat outside in stacks for a while but haven’t seen it before. I probed them and they are soft no more than 1/8" deep. The client thinks they are rotting and need to be replaced. Has anyone seen something similar to this.


Fungi, wood destroying organism. Could have been on the wood prior to delivery. Any moisture issues? Was it one piece or widespread?

White pocket rot.


probably there before the wood was dried

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Yep, that is what I typically see and I do not report on an isolated piece. However, other conditions may change my mind such as widespread moisture issues, wood rot etc.

Looks like pre-mill insect damage. I don’t think there’s anything “on” the rafters. The discoloration is where the outer layer of the wood is missing. The saw basically cut open the galleries at the mill.


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There weren’t any moisture issues at all. The problem is on about 1/3 of the ridge board.

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Live and Learn. I’ve seen that from time to time and the wood members always seem sound, so I never thought a lot about it. After your post, I did some research. White pocket rot is usually in heartwood and dies with the seasoning and drying process. It does not weaken the wood and the wood can be and is used for framing.


Thanks Lon & Simon,
I had never heard of white pocket rot before Simons post and haven’t had a chance to research it yet but will look further this afternoon.