Does anyone have advice on selecting a grade for old lumber that was sawmilled before the current grading system? I am looking at engineering a renovation of a 100 year old building, constructed with lumber which is obviously a better grade than #2 SYP. Are there experts who can evaluate the lumber? Or is it up to the structural engineer to assign a lumber grade by making an educated guess?
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advice on selecting a grade for old lumber 1
- Thread starter MikeE55
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There are some field grading guidelines that can be used for field grading lumber (See attached from the US Parks Dept.), but I doubt you are going to be able to grade field grade in place lumber and arrive at better than #2 for a whole floor system. You are very likely to reach No.1 for specific members, but it would be a very time consuming process to grade a whole floor system (and a good chance that there would be random pieces with knots too close to the tension face or a grain slope issue).
Historic structures are sometimes assigned higher design values than current codes based on in place grade and the historic strength of old-growth forests versus the relatively young trees harvested today. If you are trying to justify a strength close to today's #1 So. Pine you may have a good chance of reaching it, but you may have to grab some historic codes (think historic codes or engineering handbooks from around the time of construction - Carnegie Pocket Companion or similar), along with your field grading data to reach it.
Historic structures are sometimes assigned higher design values than current codes based on in place grade and the historic strength of old-growth forests versus the relatively young trees harvested today. If you are trying to justify a strength close to today's #1 So. Pine you may have a good chance of reaching it, but you may have to grab some historic codes (think historic codes or engineering handbooks from around the time of construction - Carnegie Pocket Companion or similar), along with your field grading data to reach it.
Another useful resource is the US Dept. of Agriculture Wood Identification services.
It looks like they no longer id samples from businesses, but I have used them in the past to confirm a species for an owner. There are similar services that will do this for a small fee.[ignore][/ignore]
It looks like they no longer id samples from businesses, but I have used them in the past to confirm a species for an owner. There are similar services that will do this for a small fee.[ignore][/ignore]
One more link, I forgot about this one. Great resource for species ID and geared specifically towards design value determination.
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