Tuesday, November 19, 2013

Getting Your Lumber Grade Stamped

Anyone contemplating producing lumber for construction should follow these steps before sawing.

1) Check with your local city, county, and/or state building code office to find out the exact requirements in your area. Requirements and the level of enforcement vary. Don’t be satisfied until you have seen the rules yourself. Keep a copy for future reference.

2) Purchase the softwood grading rules book that applies to the species of lumber you’ll be using. Thoroughly review the pertinent parts of the book to make sure you understand what the standards apply.

3) Once you have a written plan on how to proceed, contact the appropriate softwood lumber grading agency to discuss your plan with them and to make certain that your lumber will meet all of the requirements, such as thickness, widths, and lengths, moisture content, and required other items. Checking out all of the details before sawing can save time and wasted materials. (If going the self-certification route, make sure your certification is up-to-date)

4) Saw and dry your lumber according to your specific plan.

5) Schedule a visit with the lumber inspector, make sure you have enough time for his visit, and your area is
properly laid out for inspection. Make certain any documentation is prepared and available should the inspector ask for it.

As part of a structure, each piece of lumber carries a certain amount of load. Softwood grades for dimension and timbers have been established according to engineering methods that determine how much load each piece is capable of supporting. When a building is inspected, the inspector will look for a grade stamp on the lumber. This grade stamp is the only way for the inspector to determine if the lumber used in the structure is acceptable. The grade stamp is extremely important to building inspectors, as it is required by all building codes. The code is usually enforced at the county level, where a building permit is required before any construction can begin. The building can be rejected if the lumber is not grade stamped. The level of code enforcement can vary by county, however a lack of enforcement does not mean you can disregard building codes. Be certain to check with your county building inspector and permits office to determine exactly what is required. Past experiences may not predict future expectations. There may be some state and local exceptions when the lumber is produced and used for one’s own building projects.

Example grade stamp showing Southern Pine Inspection Bureau (SPIB) as the agency, the grade as No. 1, kiln-dried (KD) to 19 percent moisture content, heat treated (HT), and producing mill lumber 406. The species is not given but implied as SPIB deals exclusively with Southern Pine lumber.

Producers of small quantities of softwood or hardwood lumber to be used in construction can call for a “certificate inspection.” When a certificate inspection is requested, the grading agency will arrange for their first available or nearest inspector to travel to the location of the lumber. The lumber is grade-stamped, and a certificate is issued in regards to the inspection. The lumber is then eligible to be used in building construction. The owner of the lumber should be prepared to turn and move the boards for the inspector. Also, presorting the lumber by widths and lengths is important. Additional sorting by estimated grade will further speed up the process. The lumber may be rough or surfaced. Lumber having moisture content in excess of 19 percent will be marked “S-GRN.” Air-dried lumber or that with a moisture content of less than 19 percent will be stamped “S-DRY.” Sawyers should be certain that they follow the size requirements set forth by the rule writing agencies for different species. In order to finish to the sizes required, lumber must be cut oversized to allow for shrinkage during drying, planing, and sawing variation.

In most of North America, using your own lumber for construction material is an option available to you, and in some places, it is actually encouraged and rewarded. We hope that this short introduction to the topic has given you some good direction to finding out how to go about it in your own area. Rules can change, so ten years from now, when you pull out this article again to reference, the bottom line will still apply: Find out what your local requirements are, and abide by them!

For current rule writing and grading agency lists:
American Lumber Standard Committee

Canadian Lumber Standards
Accreditation Board