Lathing and Plastering (C-35) · Lesson 6 of 6

Plasterers Scaffold and Mixer Guard Rules

"Plasterers Scaffold and Mixer Guard Rules" is lesson 6 of 6 in the Lathing and Plastering (C-35) Learning Hub. It opens with "Which Scaffold Section Plasterers Use" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Which Scaffold Section Plasterers Use
  2. Uprights, Ledgers and Ties
  3. Platform Dimensions
  4. Railings at 7 1/2 Feet and Above
  5. Plaster Mixer Guards

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Uprights along the wall" through "Mixer grid".

What you'll be able to do

  • Explain the main idea of "Plasterers Scaffold and Mixer Guard Rules" in plain language you can use on the exam.
  • Apply this step with confidence: "Platform Dimensions".
  • Apply this step with confidence: "Railings at 7 1/2 Feet and Above".
  • Apply this step with confidence: "Plaster Mixer Guards".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Plasterers Scaffold: Light-Duty Pole Scaffold LimitsEND VIEW, 14 ft PLATFORM (not to scale)wallgrade42 to 45 in7 ft max7 ft maxtop railmidrailledgers8 CCR 1640 LIGHT-DUTY EXTERIORHeight 20 ft max; uprights 2x4 or heavierUprights: 3 ft max at right angles to wall,10 ft max center to center along the wallRibbons and ledgers: 7 ft max verticalTies: 20 ft max apart, across and upPlatform: 20 in wide min, within 14 in of wallPlanks lap ledgers 6 in minLevels 7 1/2 ft or more above grade:2x4 top rail, top edge 42 to 45 in abovethe platform, plus midrails (8 CCR 1620)8 CCR 1698(e) MIXER GUARD (1 yd or less)Grid opening 16 sq in max; 5 in min fromtop of grid to top of mixing paddlesWORKED NUMBERS: 40 ft WALL, PLATFORM AT 14 ftUprights: 40 / 10 = 4 bays = 5 uprights per line x 2 lines = 10 uprightsLedger levels: 14 / 7 = 2 spaces (ledgers at 7 ft and 14 ft); ties: 40 / 20 = 2 spaces = 3 ties per rowTop rail edge: 14 ft + 42 in = 17.5 ft to 14 ft + 45 in = 17.75 ft above gradeMixer grid: 4 in x 4 in = 16 sq in passes; 4 in x 5 in = 20 sq in failsSource: 8 CCR §1640(a)-(b), §1620(a)(1), §1698(e)CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Which Scaffold Section Plasterers Use

Title 8 of the California Code of Regulations (8 CCR) section 1640 covers light-duty wooden pole scaffolds to be used by carpenters, lathers, shinglers, painters, plasterers, sheet metal workers or other trades not using heavy tools or storing heavy materials on the scaffolds. Work that uses heavy tools or stores heavy materials on the deck falls outside this light-duty section. The exterior light-duty rules are in 1640(b), and the interior light-duty rules are in 1640(c).

Step 2: Uprights, Ledgers and Ties

Under 8 CCR 1640(b)(1), for heights not to exceed 20 feet the uprights are 2-inch by 4-inch lumber or heavier, spaced not more than 3 feet between uprights at right angles to the wall and not more than 10 feet center to center parallel to the wall. Uprights on a slippery surface need a continuous sill, and on earth they rest on the equivalent of a 2 x 10 x 10 inch wooden base. Under 1640(b)(2), ledgers spanning not more than 3 feet use two pieces of 1 x 6 board, one on each side of the uprights, single 2 x 4 ledgers are not permitted, and vertical spacing of ribbons and ledgers shall not exceed 7 feet. Under 1640(b)(3), the scaffold is tied to the building with ties not more than 20 feet apart horizontally and vertically.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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