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This may be a really stupid question, but 1.) where on the lumber or stamp is this marked?–I only know about 1,2, etc. in terms of trim materials- # of knots and such.
2.)(here comes the
i really
stupid part) Why is this important? Is it for compression strength? I can get why you wouldn’t want alot of knots in say, sixteen foot 2×8 rafters, but where else would this come into question?
Sheepishly,
Clay
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Can someone either point out a site or give a run down on Lumber grades and methods ( visual/machine ) please.
*Good day Mark,You may want to try metriquard.com first.Gabe
*I'm not an expert on the subject, but I'll tell ya what I know, as best as I understand it. There are 3 types of lumber grading - visual, MSR, and MEL. Visual grading literally means someone just looks at a piece, and assigns a grade to it. This is where the most common grades come from, like #2, #1, or stud grade. MSR lumber stands for "Machine Stress Rated". The lumber is passed through a machine that bends it a little. The machine measures how much force it takes to bend it, and assigns a grade to it. The grades typically look like "MSR 1650" stamped on the boards. MEL lumber is "Mechanically Evaluated Lumber". Lumber is passed through an X-ray machine, and X-rayed every 1/2 inch. The machine takes a composite of the X-rays, and assigns a grade based on that info. These grades look like "MEL M19". This type of grading isn't very common. Around here, this type of lumber is sometimes used in larger sized chords in roof trusses. Does this answer what you're looking for ?
*Ron'Thanks...only problem is I'm in Australia so a lot of the ratings don't mean anything..so is # 2 your best grade/thanksmark
*Gabe,Thanks for that... unfortunately I,ve been unable to access that site.Mark
*Sorry Mark,Stupid mistake on my part, Metriguard.comThey make the mechanical testing equipment you refer to and have some interesting comments as well about other testing proceedures.Gabe
*MarkIn Canada the best grade of framing lumber is i Select Structuralwhich these days seems only available in the bigger sizes, 2x10 & 2x12followed by #1, and then #2. So called "stud grade" (formerly i utilitygrade) shows up in 2x4's at places like Home Despot and is real crap - i propeller grade.Most lumber yards buy lifts of #1 & #2 mixed, especially in 2x6 & 2x8 sizes. You have to be on good terms with the yard boys to be able to sort, when you phone and have it delivered, you take what comes off the stack.Sometimes, if they are cheaping out, they'll have only #2. . . that's when I go shopping!! I've never seen any mechanically graded lumber, in fact the last lot of 2x10's I had, had the grading crayon stroke (red for #1/ blue #2) as well as the "official" stamp.-pm
*This may be a really stupid question, but 1.) where on the lumber or stamp is this marked?--I only know about 1,2, etc. in terms of trim materials- # of knots and such.2.)(here comes the i reallystupid part) Why is this important? Is it for compression strength? I can get why you wouldn't want alot of knots in say, sixteen foot 2x8 rafters, but where else would this come into question?Sheepishly,Clay
*Hi Clay,With regards to your last question first. In order to set a standard that will be recognized throughout the world. For example, 1/3 of Canada is covered in forest, mostly softwoods, each year we produce about 13 thousand million board feet per year, 2/3 of which is exported. Grading is done by a member of the Canadian Lumberman's Association or by the Canadian Standards Association. This is done under a recognized agreement for lumber quality and ensures quality in world markets.The following grades are the most common;Select, which is further divided by grades A, B, or C. Used in millwork etc.No 1 common, the top grade of framing and structural, clear, no defects, no damage, good grain.No 2 construction grade,most commonly used in structural framing.Standard,commonly used for forming, framing Utility, low grade for bracing or formingand Economy, which is defective or damaged.Hope this helps a little bit.Gabe
*ClayAny piece of dimensional lumber has load and span capabilities. . . check out your building code load and span charts, they are all calculated by species and grade. Even a 2x4 can be used for joists or rafters, but its span and use are ultimately determined by grade.All 2x lumber in Canada has a grade stamp which shows which grading standard was used, the grade, whether its dried or green, and often the mill number where it was processed. The stamp is about the size of a silver dollar.-pm
*Clay - I don't find your questions stupid at all. Everyone has their things they specialize in - we can't all know everything. As for your question #1.) where on the lumber or stamp is this marked?Look for some kind of ink stamp somwhere on b someof the boards. (they don't all get stamped, for some reason) You'll see some of the following things:SYP (southern yellow pine)SPIB (southern pine inspection board)SPF (spruce, pine, or fir from Canada)S-dry (surface dried)KD (kiln dried)There should also be some sort of grade mark, like #1, #2, or stud. There might be other mill marks, etc. There might be other things on the boards that mean something - these are just a few that I'm familiar with. As for your question #2 Why is this important?Lumber is rated 6 different ways: Bending, compression parallel to the grain, compression perpendicular the grain, tension parallel to the grain, shear, and modulous of elasticity. (Don't ask me to explain them all)Each grade, size, and species has allowable values for all 6 of these. These values are used to determine the span capabilities of floor joists, rafters, and roof trusses. Is that enough to confuse ya, or should I go on ?