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Lumber grading rules are a set of criteria used to determine how various characteristics, such as wane or knots, affect the structural performance of dimension lumber or the aesthetic value of Appearance Grades. Lumber manufacturers are responsible for grading the lumber to these rules and RIS, as part of the American Lumber Standards system, helps assure that Redwood lumber meet stated product quality standards. 

The Redwood Inspection Service (RIS) is exclusively authorized by the American Lumber Standard Committee to formulate grading rules for redwood lumber established in accordance with Product Standard 20-94, the American Softwood Standard, issued by the U.S. Department of Commerce.

RIS, a division of the California Redwood Association (CRA), publishes and maintains the Standard Specifications for California Redwood Lumber Grades.

BUYER BEWARE WARNING: The pattern measurements below are CRA industry standards. HOWEVER individual mills often have their own pattern standards which vary from the norm (usually smaller). When you get ready to buy be sure to ASK for the exposed width to make sure you are buying enough SQFT of Redwood Siding to complete the job!

Redwood "LAP" Siding Pattern Diagrams

(1) SHIPLAP Patterns 761-763 one inch S2S

Redwood SHIPLAP Pattern 761-763

(2) COVE/GERMAN/DUTCH LAP Patterns 770-772 one inch S2S

Redwood COVE/GERMAN/DUTCH LAP Patterns 770-772

(3) CHANNEL LAP Patterns 774-776 One inch reveal square channel S2S

Redwood CHANNEL LAP Patterns 774-776

(4) CHANNEL LAP Pattern 773 One & 1/2 inch reveal beveled channel S2S

Redwood CHANNEL LAP Pattern 773

Redwood BEVEL Siding and Paneling Pattern Diagrams

(1) Bevel Patterns 320-323R 1/2 inch Rabbeted Resawn S1S2E

Redwood Bevel Pattern 320

(2) Bevel Patterns 329-331R 3/4 inch Plain Saw Textured S1S2E

Redwood Bevel Pattern 329

(3) Bevel Patterns 360-363 1/2 inch Plain Saw Textured S1S2E

Redwood Bevel Pattern 360

(4) Bevel Patterns 371-373 3/4th inch Rabbeted Resawn S1S2E

Redwood Bevel Pattern 371

(5) Bevel Patterns 391-393 3/4th inch Rabbeted Saw Textured S1S2E

Redwood Bevel Pattern 391

(6) Bevel Patterns 422-424 1 1/4 inch Plain Saw Textured S1S2E

Redwood Bevel Pattern 422

(7) Bevel Patterns 476-477 1 1/4 inch Rabbeted Saw Textured S1S2E

Redwood Bevel Pattern 476

(8) Bevel Pattern 400 1/2" x 4 inch Rabbeted Round Edge S1S2E

Redwood Bevel Pattern 400

(9) Bevel Pattern 430 1x6 inch 2 Lap Round Edge Drop S1S2E

Redwood Bevel pattern 430

(10) Bevel Pattern 431 1x8 inch 2 Lap Round Edge Drop S1S2E

Redwood Bevel pattern 431

(11) Bevel Pattern 433 1x10 inch 3 Lap Round Edge Drop S1S2E

Redwood Bevel pattern 433

Redwood T&G Siding and Paneling Pattern Diagrams

(1) T&G Patterns 204-206 5-8-inch V1S-S2S 3-32-V

Redwood T&G Patterns 204-206

(2) T&G Patterns 709-713 1-inch V1S-S2S 1-4-V

Redwood T&G Patterns 709-713

(3) T&G Patterns 707-716 1-inch V1S-S2S 3-32-V

Redwood T&G Patterns 707-716

(4) T&G Patterns 709-713R 1-inch V2S-S1S-Saw-1S 1-4-V

Redwood T&G Patterns 709-713R

(5) T&G Patterns 707-716R 1-inch V2S-S1S-Saw-1S 3-32-V

Redwood T&G Patterns 707-716R

(6) T&G Patterns 732-734R 1-inch V2S-S1S-Saw-1S 1-4-V

Redwood T&G Patterns 732-734R

(7) T&G Patterns 726-728R 1-inch V2S-S1S-Saw-1S 1-8-V

Redwood T&G Pattern 726-728R

(8) T&G Patterns 632-634 1-inch S2S-CM

Redwood T&G Pattern 632-634

(9) T&G Patterns 632-634EE 1-inch EE S2S-CM

Redwood T&G Patterns 632-634EE

(10) T&G Patterns 616-617 1-inch V&CV-S2S 1-4-V

Redwood T&G T&G Patterns 616-617

(11) T&G Pattern 606 1-inch S2S

Redwood T&G Pattern 606

(12) T&G Patterns 16-18 1-inch S2S-CM paneling

Redwood T&G Patterns 16-18

CAL REDWOOD PATTERN BOOK
CAL REDWOOD PATTERNS
CAL REDWOOD Complete Guide PDF

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