Understanding Grading Standards

Lumber grading is one of the most misunderstood topics in the building industry — and when reclaimed wood enters the picture, confusion multiplies. Grades like FAS, #1 Common, and Select may sound familiar, but how do they apply to a 120-year-old barn beam? The short answer: they don't, at least not directly.

This article walks through the standard grading system, explains where reclaimed wood diverges, and details our own three-tier grading system so you know exactly what you're getting when you order from North Iowa Lumber.

Overview of Lumber Grading

Lumber grading exists for a simple reason: buyers need a standardized way to know what they're purchasing without inspecting every individual board. A grading system establishes consistent criteria for defects, clear yield, dimensions, and moisture content — so that a #1 Common board from a mill in Oregon is comparable to a #1 Common board from a mill in Virginia.

Grading systems vary by lumber type. Hardwoods and softwoods follow different standards, and structural lumber is graded differently than appearance-grade stock. The two primary systems in North America are:

NHLA Grading Standards in Detail

Since most reclaimed lumber is hardwood — oak, pine, chestnut, maple — the NHLA system is the relevant benchmark. NHLA grades are based on the percentage of each board that yields clear-face cuttings of a minimum size. Here is how the grades break down:

NHLA grading is performed at the mill on freshly sawn lumber. Inspectors evaluate both faces, measure dimensions, and check moisture content. The system works well for new lumber because every board starts from a known baseline — a freshly felled log with predictable characteristics.

How Reclaimed Wood Is Graded Differently

Reclaimed lumber does not fit neatly into the NHLA system for several reasons. Understanding these differences is critical to setting realistic expectations — and to appreciating why reputable reclaimed suppliers develop their own grading criteria.

The fundamental challenge is that NHLA grading treats character marks as defects to be avoided, while the reclaimed market often values them as features. A barn board with nail holes, saw marks, and a weathered patina would grade poorly under NHLA rules — but it may be the most sought-after board in a designer's specification.

Additional factors unique to reclaimed grading include:

• Structural integrity: Has the wood been compromised by rot, insect damage, or prolonged moisture exposure? Surface character is one thing; internal decay is another.
• Embedded metal: Old nails, screws, bolts, and wire can lurk beneath the surface. Thorough de-nailing and metal detection are essential before grading.
• Species verification: Decades of paint, stain, and weathering can obscure species identification. Accurate grading requires confirming the actual species, not guessing from appearance.
• Moisture history: Reclaimed wood may have cycled through wet and dry environments for decades. Kiln-drying to stable moisture content is necessary before grading for dimensional accuracy.
• Dimensional variation: Unlike new lumber milled to standard dimensions, reclaimed boards may be irregular. True 2-inch-thick planks, non-standard widths, and taper are common.

Our Internal Grading System

To bridge the gap between standardized grading and the realities of reclaimed lumber, we developed a three-tier system that communicates both structural quality and visual character honestly. Every board we sell is inspected individually, assigned a grade, and labeled before shipping.

What to Expect with Each Grade

No two reclaimed boards are identical — that is the nature of the material and a large part of its appeal. But our grading system is designed to set clear expectations so there are no surprises when your order arrives.

We encourage clients to order a sample pack before committing to a large order. Seeing and touching each grade in person eliminates ambiguity and ensures the material matches your vision. Sample packs include two to three pieces per grade and ship at a flat rate.