Hardwood Lumber Grades Explained
“Wood is a natural material and by its very nature may contain different characteristics and defects that need to be understood and allowed for in any given application. The grading of sawn wood into categories as it is processed helps to determine to a large extent the value and potential use possible for each board of sawn lumber.”
– American Hardwood Lumber Council
Worldwide, hardwood lumber producers “grade” their lumber, assuring downstream consumers of the lumber of the lumber’s quality for the intended use. Put simply, lumber grading serves quality assurance needs.
The Simplified Process of Determining Hardwood Lumber Grades
The hardwood grading rules are quite complex and require study. A very simplified, condensed overview of the steps for grading a piece of hardwood lumber is as follows:
- Determine the species. Some species must be processed according to special rules.
- Determine the surface measurement (SM). SM is the width, in inches and fractions, times the standard length in feet with no fractions or rounding, divided by 12 with the answer rounded to the closest whole number.
- Determine the poor face, which is the side with the lowest grade.
- Assume a trial grade for the piece of lumber and then see if all the conditions for that grade are met.
- Determine if lumber size requirements (length and width) are met for the chosen grade.
- Determine the number of clear cuttings that are permitted.
- Determine the cutting yield required by multiplying the surface measurement (SM) by the grade values respectively. The required yield is expressed in cutting units. A cutting unit is 1 inch wide by 1 foot long.
- Locate cuttings to obtain the maximum area; then calculate the cutting area. Make sure the cutting sizes are not below the minimum size for the trial grade.
- When the piece grade is No. 1 common, check the reverse side to see if the reverse is FAS grade. If so, and if a few other requirements are met, then the piece is Select or FAS 1-Face.
- Check to make sure that the piece qualifies for the anticipated grade in all other respects, which include the amount of wane, the amount of pitch outside the cuttings, and so on.
Make sure to get the most accurate moisture reading with an Orion pinless moisture meter.
Hardwood Lumber Grading Categories
Standard Grades of Hardwood Lumber
|Grade||Trade Name||Min. Board Length||Min. Board Width||Min. Cutting Size||Min. Area of Clear Cuttings Required |
|First & Seconds||FAS||8'||6"||4"x5' - 3"x7'||83-1/3%|
|FAS 1-Face||F1F||8'||6"||4"x5' - 3"x7'||83-1/3%|
|Select||SEL||6'||4"||4"x5' - 3"x7'||83-1/3%|
|No. 1 Common||1C||4'||3"||4"x2' - 3"x3'||66-2/3%|
|No. 2A Common||2AC||4'||3"||3"x2'||50%|
|No. 2B Common||2BC||4'||3"||3"x2'||50%|
|No. 3A Common||3AC||4'||3"||3"x2'||33-1/3%|
Several assessments lead inspectors to grade lumber according to certain categories. There are eight hardwood lumber grades in widespread use at this time. FAS is the highest and No 3B Common is the lowest grade.
Hardwood Lumber Grades in Detail
FAS: Shorthand for “First and Seconds”. FAS is the highest of the hardwood lumber grades.
FAS 1-Face (abbreviation: F1F): A “Select” piece of lumber which is six inches and wider.
Select: A No. 1 Common piece of lumber (the poorer side of the wood piece is assigned as No. 1 Common grade) and the reverse side (the better side) grades FAS. The price of Selects and 1-Face is usually the same as FAS. Often, Select grade lumber is used in the Northern U.S., while 1-Face is used in the South.
No. 1 Common is the standard furniture grade lumber and provides a good selection of long, medium and short cuttings at a reasonable price.
No. 2A Common (also known as No. 2 Common) is the standard grade for cabinets, millwork, and other uses requiring medium to short cuttings.
No. 2B Common is the same as No. 2A Common, except that stain and other sound defects are admitted in the clear cuttings. It is an excellent grade for painting.
No. 3A Common is often combined with No. 3B Common, and the combination is sold as No. 3 Common, which is widely used for flooring and pallets.
No. 3B Common is graded on the basis of sound cuttings rather than clear cuttings. It is widely used for pallets and crates.
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Understanding lumber grading categories can help with both selecting the appropriate wood stock for your intended woodworking project and, with the help of an accurate wood moisture meter, for ensuring a successful and satisfying end product service life as well.
Knowing the importance of moisture measurement and management all through your woodworking or wood flooring projects is crucial to achieving the best in performance and durability. Wagner Meters offers accurate solutions for those moisture management priorities.
As Sales Manager for Wagner Meters, Ron has more than 35 years of experience with instrumentation and measurement systems in different industries. In previous positions, he has served as Regional Sales Manager, Product and Projects Manager, and Sales Manager for manufacturers involved in measurement instrumentation.
Last updated on July 30th, 2021
Hi I was wondering why defects such as bows, cups and twists in the lumber are disregarded in grading ? Would it not be expected that the usable percentage of a FAS board that is 5 /4 be able to be milled to a flat square 4/4 ?
If you’re in North America, I suggest you ask that question of the National Hardwood Lumber Association (NHLA), https://www.nhla.com.
They will be able to answer this question more accurately.
hi. What grading would a B grade hardwood floor be considered in grading system? it is European solid white oak. The technical sheet says it is a high grade with a mixture of A and B grade.
In North America, there are no such hardwood lumber grades as just A & B. The designations from National Hardwood Lumber Association in the US have grades such as Number 1A, 2A, etc. Again, no standalone A and B. I am not familiar with grade designations outside of North America.
Hope that helps.
What grade and type of Australian hardwood do you recommend for jetties in salt water?
From this site: https://www.woodsolutions.com.au/articles/wood-species-their-properties
Question: What hardwood is suitable for a boat jetty in a salt water environment, it is over salt water not in it and could be treated away from the water before being fitted.
Answer: Wood generally tolerates a salt environment quite well – fresh water is actually more hazardous since it is more conducive to mould and fungal growth. If you were planning to put the timber into salt water it would be a different story – not because of the salt, but because of marine borers. However, above the water any Durability Class 1 hardwood would be satisfactory, for example tallowwood, turpentine, spotted gum, river red gum and so on. No special treatment is necessary, but make sure all fasteners are stainless steel.
Hope this helps.
What grade would you suggest for someone who is making end grain cutting boards?
Thanks in advance
The grade of the lumber will not necessarily affect the integrity of the furniture piece construction at all. This is really about the appearance of the piece, and that can be very subjective. The higher grades of lumber, with a lot of clear wood, just command a better price for the sawmill; all about money. FAS-grade lumber commands a higher price, but if you purchase Commons or 2’s and 3’s, the wood may be beautiful and perfect to use for what you are doing. If you are, on the other hand, a manufacturer (rather than a hobbyist), it is in your best interest to get the clearest lumber for your money, as you are purchasing a high volume of lumber from mills every year.
Good morning Ron ,
Peter here in Australia . I am using an old US standard to design roof trusses . It calls for 1100f lumber , 1400f lumber and 1600f lumber in calculations . What do these numbers mean please ,
Kind Regards ,
Unfortunately, I am unfamiliar with those old standards.
we are doing a deck for a client who wanted to use certified ipe. trying find a source for that was very difficult and frustrating. he finally settled on reclaimed wood for the planking. he found a source for peroba wood that was reclaimed from a plantation in brazil . the lumber was 2 and 1/8th thick and about 13 feet long by 5 to 6 ” wide with nails. we had these timbers milled 15/16th at 3 different widths and had them grooved for a clip system. we met with the local building inspector who asked that the wood be certified or graded. what can be done to salvage this project? are we faced with very costly process?
Hi Ron. Is there such a thing like 4C grade in lumber specially in White Oak?
Eric, I am not aware of any National Hardwood Lumber Association grade designation such as that, but I would contact NHLA for more detailed information.
WE are interested in knowing which type of flooring has the best ratings for scratching we own several dogs and have concerns about them scratching the floor after it is installed?
Thank you for the question. This topic can give varying opinions, some being if wood is even the best option given your household “make up”. Here is a blog link from one of our wood flooring exclusive distributors that may help. https://blog.cityfloorsupply.com/best-hardwood-floors-for-dog-owners/ Good luck.
Thank you for the information.
Are you aware of “S1F Grade”? came across this while purchasing some Alder. Apparently better than 1COM. Any input would be appreciated.
I am unfamiliar with it. It sounds like it might be a proprietary grade; not sure.
Can you tell me what MSR 1800F-1.8 GRADE. Means
I am unaware of that Machine Stress Rated (MSR) grade designation. Please use this link to view the different grade designations:
Thank you for posting the information on Hardwood Lumber Grading.
While reviewing we noticed something of interest.
re: FAS 1-Face (abbreviation: F1F): A “Select” piece of lumber which is six inches and wider.
Would it be a good thing to also mention the ‘length’ as being eight feet and longer? Since six inch wide Select is not F1F at six or seven feet in length.
Thank you for bringing this to us to our attention. We will be making some revisions to this article at a future date.