×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Field Guide Wood Inspection

Field Guide Wood Inspection

Field Guide Wood Inspection

(OP)
Does anyone know of a good field guide, with pictures, for inspection of wood structures?

I was observing a structure yesterday that has white and brown mold or fungus on the surface of 2x10 wood roof joists. I do not know exactly what this is, nor, how damaging it is.

A field guide would be helpful.

RE: Field Guide Wood Inspection

Sounds like maybe the roof is not being vented too well.

One in the hand is worth two in the bush.

RE: Field Guide Wood Inspection

Link. From the good folks at the forest products lab.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Field Guide Wood Inspection

(OP)
Thanks guys. I appreciate it.

I've attached a photo as to what I'm looking at. I'm looking at a roof area that's only about 15' x 10' at the top of a bell tower. The joist were once subject to a lot of moisture, but now, the roof leaks have been stopped and the wood has dried back out. I took several moisture measurements and found the moisture content between 10% and 12%. The wood was hard.....it was not spongy.

I'm thinking that most of this decay is surface only. I'm thinking that the decay stopped when the moisture exposure was stopped. This structure is more than 125 years old, so I am not wanting to modify much of it if I can help it. I'm thinking that I may have them clean off the fungi/mold, coat the wood in an anti microbial, and then just have the owner monitor it over time.

RE: Field Guide Wood Inspection

Marinaman:
Well..., you are trying to determine if there is significant decay, right, surface or otherwise? And, you can see some fungus and mold on the joist and floor board surfaces, caused by moisture. I’d take an ice pick or a thin screw driver and pick around a little to make sure that the wood is solid on its interior. I would particularly look at the bearing points of the joists for significant deterioration. Has there been any relative movement (particularly vert. movement) btwn. the joists and the blocking btwn. the joists? That is, settlement of the joists due to bearing loads and rot, w.r.t. the lightly loaded blocking. You might look at the deflection of the joists with a string or some such, to see that this is not excessive. You might also have mold removal done, or just do something as simple as spraying the wood a few times with some chlorine bleach, or some such, to settle the mold down a bit. If you’ve stopped the roof leakage, you’ve probably pretty much solved the problem. And, you might also consider venting that attic space in some way so there isn’t a humidity build-up in the future. Churches aren’t usually likely to be too humid, but there might still be some heat and moisture vapor movement up into that space from below. Do something to minimize that moisture/heat movement. You might have to heat tape that roof drain.

RE: Field Guide Wood Inspection

Read the US Forest Service Wood as an Engineering Material handbook (google will find it for you). Wood loses significant strength before it loses significant hardness. An awl is a handy tool to find really bad material when it doesn't look bad, but if you can see evidence of mold, fungus, or decay you can pretty well rest assured that there is a big problem. Unless the members were well oversized to start with, replace them.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources