Secton loss test for timber

[cmbyrd77]

I am looking for a good "industry standard" test to check for section loss of wood structural members. I am currently working on an inspection of a wood-framed apartment complex with wood foundations. Any literature or advice would be greatly appreciated as timber is one of my weaker materials I've worked with (no pun intended).

 

[BAretired]

If PWF material was used for the foundations, there should be no section loss. If visual inspection reveals section loss, the affected parts would need to be replaced.

BA

 

[cmbyrd77]

I guess I was asking more of what would be a good visual inspection test (or rule of thumb). I've heard some guys say they've used a pocket knife to see how well it flakes of or how easily it sticks in the wood.

 

[dicksewerrat]

Some housing inspection classes cover wood dry rot. Call a few inspectors and ask.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[MiketheEngineer]

What you are asking is about rot. There is no thing such as dry rot - it is wet rot that has simply dried out.

Tear into it - see what is still "good" - reduce your section and go from there. Get rid of moisture!!

 

[dhengr]

If everything you can see, in the way of structure, is dry, that’s a pretty good sign that the water proofing system is in good shape. Look particularly in unfinished spaces where you can see the wall structure. You may have to open up some areas. Look in areas where ext. grading doesn’t provide good drainage away from the bldg. If there are places with interior water problems that’s where you should spend your time. And, that ext. water proofing must be fixed. Be very careful with a jack-knife, the blade has a nasty habit of closing on your fingers which are around the handle. Use an ice pick or a long slender, small blade, screwdriver, or some such, instead. Test the wood for soundness particularly if there have been water problems, dry wood vs. stained wood. Is the wood sound, is the appropriate wood treated to the correct spec. for PWF’s, is the lower level dry? Are there any inward bulges in the bsmt. walls, a sign of a failed stud. Carpenters have a habit of forgetting that the inner edge of the studs is in tension and knots, etc. should be avoided on this edge, just like the bottom edge of a fl. jst. Check the connections, hardware and blocking at the top of the wall and to the fl. diaphragm, for adequacy and any movement. Does the wall have good support at the bsmt. fl. slab? That’s about it, after all it has stood for 15 years already, and is still dry.

 

[shobroco]

Sorry guys, but wood can lose a huge precentage of its strength from rot long before it loses any density. If you aren't familiar with this type of inspection, get training or hire someone who knows his stuff. For a quick course in the problems that you will encounter, read the relevant sections of something like the Wood Handbook, Wood as an Engineering Material
Publication: Forest Products Laboratory, U.S. Department of Agriculture, Forest Service, Forest Products Laboratory

 

[shobroco]

The following article from the 1999 USDA wood manual should be of interest to more than just the OP.

Unlike mold and stain fungi, wood-destroying (decay) fungi seriously reduce strength by metabolizing the cellulose fraction of wood that gives wood its strength. Early stages of decay are virtually impossible to detect. For example, brown-rot fungi may reduce mechanical properties in excess of 10% before a measurable weight loss is observed and before decay is visible. When weight loss reaches 5% to 10%, mechanical properties are reduced from 20% to 80%. Decay has the greatest effect on toughness, impact bending, and work to maximum load in bending, the least effect on shear and hardness, and an intermediate effect on other prop¬erties. Thus, when strength is important, adequate measures should be taken to (a) prevent decay before it occurs,
(b) control incipient decay by remedial measures, or (c) replace any wood member in which decay is evident or believed to exist in a critical section. Decay can be prevented from starting or progressing if wood is kept dry (below 20% moisture content).

No method is known for estimating the amount of reduction in strength from the appearance of decayed wood. Therefore, when strength is an important consideration, the safe proce¬dure is to discard every piece that contains even a small amount of decay. An exception may be pieces in which decay occurs in a knot but does not extend into the surrounding
wood.