Pro Construction Guide: The species of lumber and lumber grades available will often vary depending on which region you are in. In California, for example, the predominate species of dimensional lumber used for home building is Douglas Fir-Larch (DF-L). As you move east, lumberyards stock both DF-L and Hem Fir (HF). Once you get into the Southwest, you may use Spruce-Pine-Fir (SPF). All of these are considered softwoods and are graded under the American Softwood Lumber Standard PS 20.
7 comments:
I definitely did not go into this article believing that I would find its contents all that interesting. However, I really learned a lot from this article. We talked in brief during Kevin's Basic Production Technology & Management course about dimensional lumber and its properties. I did not realize, though, that lumber is graded for quality in the same way that one might grade sheet material like plywood, luaun, or masonite. Though obviously the dominant species of tree differs by region, I had not thought about how the varying properties of species could affect the finished lumber product. Here at CMU, I figure we consistently purchase the same type of lumber to build with for each production. However, in the professional world, I believe it would be safe to assume that the scenic designer or technical director would have to specify what type of lumber they want for the production. As such, it is definitely important to understand lumber grading and its implications in the build process.
A very interesting and informative article. I had no clue that lumber had such a specific and complex grading system to determine these factors. However, this all makes sense as it mentioned; the lumber is being used for certain applications and it should fit up to the job it is being required to perform. Being in theatre, look and functionality are very important so it was very nice to find out there is structural grade and appearance grade. This article talks about structural and I had not known that lumber required so much as the moisture content to be known and considered heavily. Having the mill number, I find smart because the origin of something is quite useful for tracking down when you have to and having to track down that origin happens more than often than you want it to. Overall a very informative article and one I will be saving to reference occasionally.
Typically we use what we know works and has worked for us in the past. When we start having to run the numbers in order to see if something will work most often we are looking at requiring a change in materials. When I think about different grades of lumber than what I am usually going to use it is because of a change in the region or the desired finish. In all of what little time compared to some in this industry I have had to know and recognize the stamps and what they meant was when I worked in a lumber yard or was receiving orders for shops. The times that I found it convenient to know were when in the shop there was no real organization to speak of thus requiring one to be able to recognize the differences by more than merely feel and sense. Overall this article gave an excellent overview of the definable stamps used to indicate information about lumber grades and species.
Lumber Grade’s is something that I feel I have understood in theory for a long time but I must have been wrong there was so much that I was just ignoring and missing in terms of the grade for structural lumber. I also was wrong about the grades in terms of what the number quality meant. I always thought that it had to do directly with the appearance and with the amount of knots and deformations in the wood along with how straight the grain may be in the boards. The saw mills tag is also interesting as I was unaware that there was their own tag I always thought it was just a random tag for the orders on the lumber. The moisture content and the species of lumber make sense as well. It’s interesting to me having grown up in the south east I’ve rarely seen or been on build sites where the lumber specified for the job was only for specific applications within the job.
Most people when they think about the grade of lumber in general, most people just think premium, no. 2, and construction “You can’t simply assume the lumberyard will send you the correct materials. If you frame a home using the wrong materials, you’ll be held responsible for the error. If it’s simply a matter of changing out a couple of headers that should have been built with a stronger material, it isn’t a big problem. But if you frame a whole house with SPF that was specified to be framed with DF-L, you may have to take it down and build it again. Clearly, you need to understand grade stamps.“ the releative strength of each type of lumber can vary greatly and if you don’t pay attention to it it could mean a major downgrade in the total strength of the structure. In brief the moral of the story is call an ask.
This was a semi-interesting article. I can't really say I gleaned a lot of new information, but it was still interesting. I suppose I didn't really know much about the moisture content thing. I usually just assume that the wood comes with some moisture and when it sits on the rack for a while, it dries out and deforms. I was hoping this article would talk a little bit more about what is different inside the wood but it really just says what we learned in structures. Also, the entire article says that you have to be careful with what wood you use, and make sure it is what is specified, and that depending on your region the wood will be different, but then they mention there is a standard grade which kind of contradicts the rest of the article. I found that to be interesting, especially since I have never actually heard of a "standard" grade framing lumber.
I agree with Jeremy when he says that we typically use what we know works. In the theatrical sense, lumber grading typically impacts how easy it is to work with the material in the scene shop. The live event industry has a number of standards that are followed when constructing scenery and these standards are very rarely adjusted. However, there are a number of situations that would require the engineering strength of lumber to be taken into consideration due to safety concerns. Usually, these specific situations involve sheet goods instead of dimensional lumber. This can affect the use of machinery on the stage deck and if the lumber can support the weight of the machinery. Additionally, a theatrical show that is being built to tour may decide to build from higher quality lumber to ensure the longevity of the scenery. Personally, whenever the structural integrity of the wood is in question I would start to think if lumber is the correct material and if steel would be a better option.
Post a Comment