Ungraded Lumber in Farm Buildings

Agdex#:	714
Publication Date:	12/94
Order#:	94-105
Last Reviewed:	12/94
History:	Original Factsheet
Written by:	J. Johnson - Engineer (Structural Design)/OMAF

If you live in an area that has a significant stand of softwood lumber, you may be interested in some recent changes to the Ontario Building Code. The Ontario Building Code 1990 (OBC) has been revised to allow the use of ungraded, full-dimension lumber as a structural part of farm buildings. The OBC and the Canadian Farm Building Code (CFBC) previously made it mandatory that all wood used in structural situations be graded. There has never been a restriction on the use of ungraded lumber for non-structural components in farm buildings.

A major change came on October 1, 1990 when the Ontario Building Code made it mandatory for all municipalities to regulate farm buildings. Prior to this, farm buildings were required to meet code requirements, but inspection was not carried out in a uniform manner from one area of the province to another. For liability reasons, your building official is obligated to consider the OBC regulations. If he/she ignores the Code requirements and approves a project, they place themselves and their municipality into a position of liability if there is a structural or functional failure.

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Under the terms of the revised Ontario Building Code, there are four ways that bush lot lumber can be used in your farm project:

1. Ungraded lumber can be used in one-storey farm buildings. Building area must not exceed 600 square metres (approximately 6459 square feet). As a farmer, you are expected to inspect the lumber for soundness. Various criteria for maximum knot size and spacing, slope of grain, etc. are specified later in this Factsheet. The lumber must be cut to full-dimension (for example, a 2 x 6 will measure 2" by 6" in actual dimension). As well, the lumber must be sized according to design tables that have been included in the Ontario Building Code. The building official will also carry out a similar type of inspection of the material.
   
   Before cutting lumber for your building project, you should have your plans approved by your local building official. In this way, you will have enough of the appropriate sizes cut and cured by the time construction takes place.
   
   
2. The Ontario Building Code (1990) provides a building official with the discretion to accept your design and material on the basis of past performance. Specifically, a building official may accept ungraded lumber if, in his/her judgment, similar lumber has performed satisfactorily in the past, under the same loading conditions and in a similar configuration.
   
   
3. Lumber can be graded according to the National Lumber Grades Authority (NLGA) grading rules. In Ontario, the NLGA grading rules are applied by the Ontario Lumber Manufacturers Association, the Canadian Lumbermen's Association or the Coniferous Lumber Inspection Bureau. These organizations have graders who can travel to your farm to ensure that your lumber meets the NLGA grade standards. Both dressed and rough sawn lumber can be graded. The fee for a licensed grader is about $300 per day plus expenses (if required). The grader can be hired for a half day also. It would be appropriate for a small sawmill operator to co-ordinate the grading of wood with their schedule of cutting so that your costs could be shared with other wood lot owners.
   
   
4. A consulting engineer can specify and take responsibility for the use of ungraded lumber in your farm project. The engineer is obligated to make sure that the project is built according to the design. The building official will inspect the project, but the engineer will accept more liability. It is important for the engineer to be qualified in specifying the quality and strength of ungraded lumber.

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Regardless of the method chosen, you must work with your building official. Understand that he/she is accepting responsibility for your project. For this reason, you should contact your building official well in advance of starting to construct your building. It will be your responsibility to indicate when you are ready for the necessary inspections (by agreement with the building official).

Structural lumber used in farm buildings (when purchased) usually is graded according to the National Lumber Grades Authority (NLGA) and bears the stamp of the regional association that is responsible for their particular geographic area. These regional associations are given accreditation by the Canadian Lumber Standards Accreditation Board (CLSAB). In Ontario, commercial lumber is graded by the sawmill that produces it. The Ontario Lumber Manufacturers Association (OLMA), the Canadian Lumbermen's Association (CLA) or the Coniferous Lumber Inspection Bureau (CLIB) audit this process.

Under ideal conditions, where there are facilities and enough help to move the lumber, a grader can process approximately 20-30,000 board feet of lumber per day. Few farmers would have this quantity of lumber to grade at one time.

Regardless of the care taken by farmers and small sawmills, some lumber may not be structurally adequate for the increasing size and complexity of farm structures. Training is required to recognize the differences between species and grades of lumber. In order to design structural components, an engineer needs to know the grade of lumber before a size can be determined.

Are you interested in becoming a lumber grader? The OLMA and the CLA offer five-day courses for visual grading of softwood lumber.

The Ontario Ministry of Municipal Affairs and Housing, administers the Ontario Building Code.

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In Ontario, the use of ungraded lumber in farm building projects is an accepted practice. The Ontario Building Code allows an owner to use ungraded lumber for posts, common rafters, lintels, beams and wall studs. More critical structural components (roof trusses, floor joists, etc.), will require the use of graded lumber and in some circumstances will require an engineered design.

Remember that there are four alternatives for using ungraded lumber in your farm building (see preceding text). Your wood lot can be an important source of building materials.

Ungraded Lumber

Lumber which has not been grade stamped to indicate its grade as determined by the NLGA " Standard Grading Rules for Canadian Lumber" but which meets the following visual attributes:

• sawn to full nominal size,
• has no evidence of decay,
• has no knots which exceed 25 percent of the cross section and spaced closer than 600 mm (24") on centres,
• has a slope of grain not exceeding 1 (vertical) in 4 (horizontal), and
• is free of excess warp.

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