Grade of existing lumber unknown.

[chrisrosebud2001]

I am analyzing an existing roof for potential additional snow loads. The building roof structure is timber joists and girders. The building is very old and there are no grading stamps to be found. The lumber appears to be rough sawn spruce and from what I understand, local spruce was likely used. Does anyone have a suggestion for what grade to use. I did see an earlier thread where it was considered conservative to use S-P-F #1/#2 and that is what I was leaning towards using. Does anyone have any other suggestions?

Thanks

 

[racookpe1978]

Is the old wood itself in good/adequate shape? No bored holes or insect/dry rot/cracks from drying out/no busted out knot-holes?

 

[SkiisAndBikes]

I have had success taking small samples from a representative number of members using an exacto knife and submitting to the local college/university forestry department. For a relatively small fee they can identify the wood species.

 

[chrisrosebud2001]

I did observe cracks as well as some moisture damage. It appears there have been quite a few roof leaks over the years. However, a lot of it appears to be in good condition.

 

[Lion06]

I have had a grader come out to the site and look at the lumber. They won't tell you that it IS, say No. 1, but they will tell you that they don't see anything that would push it into No. 2.

 

[pmblair]

I wouldn't assume #1!

Here in Florida i would feel a little uncomfortable assuming Southern Pine #2, which is the most common here, and what properties and material I spec out in my designs.

 

[dik]

Just a caution... with dry-rot (brown rot), material can be weakened substantially with little observable change...

Dik

 

[jaypartain]

There is and ASTM that covers visual grading of existing lumber. I think it is ASTM D245.

Jason A. Partain, P.E.

http://www.myconstructionfinds.blogspot.com