Cracks Perpendicular to Grain in Wood Beams/Columns
Cracks Perpendicular to Grain in Wood Beams/Columns
(OP)
This structure supports a waterslide and is wet a significant amount of the year. As you can see if you look closely at the pictures attached there are small cracks running perpendicular to the grain of the timber.
Based on this article, http://forestpathology.cfans.umn.edu/microbes.htm, and the fact that the structure is constantly wet, I believe that this is brown rot (61% sure). This is occurring at both columns and beams.
I was wondering if I could get a couple of opinions on what people thought was going on in these pictures. I've inspected a number if different timber structure, but this is the first time I have come across anything that looks like this. I have come across brown rot but it is usually brittle and this is not the case with these pieces (yet). It is also worth noting that I did not drill the wood to see the condition of the core which should have been done. Your expertise is greatly appreciated as always!
Based on this article, http://forestpathology.cfans.umn.edu/microbes.htm, and the fact that the structure is constantly wet, I believe that this is brown rot (61% sure). This is occurring at both columns and beams.
I was wondering if I could get a couple of opinions on what people thought was going on in these pictures. I've inspected a number if different timber structure, but this is the first time I have come across anything that looks like this. I have come across brown rot but it is usually brittle and this is not the case with these pieces (yet). It is also worth noting that I did not drill the wood to see the condition of the core which should have been done. Your expertise is greatly appreciated as always!






RE: Cracks Perpendicular to Grain in Wood Beams/Columns
Dik
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
I will have3 to admit that I have seen less cracking in asphalting paving that has failed than these beams.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
The second photo shows what looks like extreme dry-rot, aka brown rot, conditions. Without undertaking any tests, if dry-rot, then it has likely lost over 90% of its capacity.
Dik
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
Dik
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
Does white rot have the same effect on the structural capacity of wood as brown rot does? From what Ive read brown rot is the rot to really worry about. Would you recommend two different solutions to white rot and brown rot? How long do each of the rots take to become significant? I read something that said colonies can establish themselves within 7-10 days with optimal conditions, but how long would it take for the wood to lose its structural capacity if afflicted by brown rot? or if afflicted by white rot?
Any good references would not go to waste!
Thank you for the responses and thanks to Mike for the heads up about posting in 2 forums!
Dik:
I found another thread where you recommended a book, 1989 The Encyclopedia of Wood Revised Edition / Sterling Publishing Co, I was wondering if you thought it was worth purchasing. I have wood codes and design books, but they do not have a lot of information regarding damaged wood and fungus that destroy it. Id like to read more about the effects of white rod on timber and how it effects its structural capacity. Brown rot seems pretty straightforward (dangerous), but I'd still like to have more references. These are the websites I have been reading:
http://ohioline.osu.edu/hyg-fact/3000/3300.html
http://forestpathology.cfans.umn.edu/microbes.htm
http://www.buildingpreservation.com/index.php?opti...
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
There may be a newer edition out. My current issue is 2007. It is published by the USDA and printed by Skyhorse Publishing. I've found it to be a useful text... as I recall, it wasn't too pricey. To me, it's a good book to have.
There are some other texts/publications, I'll see if I still have a bibliography... this is something where Ron can also provide a 'bunch of info'... I'll see what I can dig up.
White rot, works on the lignin, leaving the lighter cellulose can be as big a problem, although, in my experience, not as fast and is more species selective.
See the attached from another article:
White rot fungi
White rot fungi can degrade all cell wall components, including lignin. They often cause a bleaching of normal wood coloration. Their ability to metabolize large amounts of lignin in wood is unique among microorganisms. The thousands of
species that cause white rots are a heterogeneous group that may degrade greater or lesser amounts of a specific cell wall component. Some species preferentially remove lignin from wood leaving pockets of white, degraded cells that consist entirely of cellulose, while others degrade lignin and cellulose simultaneously. Degradation is usually localized to cells colonized by fungal hyphae and substantial amounts of
undecayed wood remains even after advanced decay has occurred. A progressive erosion of the cell wall occurs when components are degraded simultaneously or a diffuse attack of lignin may occur by species that preferentially remove lignin .
Strength losses are not significant until late stages of decay. White-rot fungi are common parasites of heartwood in living trees and are aggressive decomposers of woody debris in forest ecosystems.
Dik
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
In another thread there is guidance given for gauging the remaining strength of wood members after a fire; is this that far removed from that, or do these cracks run so deep that it wouldn't be fair to compare them to surface charring? Then again, I had a tree house collapse under me as a kid from plain old wet rot, so I'm not for ignoring warning signs.
I stand ready to eat crow.
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
but, your material can lose 30% or more of the strength without showing signs of deterioration or weight loss... and damage is progressive... the 'little critters' go dormant when they are dry... Judging from photo 2, the hyphae are likely thoughout the material... you can use an incremental borer and microscope to confirm...
Dik
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
RE: Cracks Perpendicular to Grain in Wood Beams/Columns
Also in your last picture you have a shot of the planking also showing rot.( left center of the picture.)
Was this lumber pressure treated before installation? Some of it appears to have a greenish cast, however that may be just the light.
B.E.