Masonry Information Bulletin - Good Scaffold Practices 1 - From the Ground Up

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Construction Safety Association of Ontario

Summary Statement

Describes the steps that should be taken to install scaffolds safely, focusing on mudsills, baseplates and leveling screws. Includes a quiz. Part of a collection. Click on the 'collection' button to access the other items.
Winter 2000/2001

 Masonry and Allied Trades Labor-Management Health & Safety Committee


Good Scaffold Practices 1 - From the ground up

• Mudsills • Baseplates • Leveling screws •

This issue is one in a series of good scaffold practices. It is a joint initiative between labor and management designed to increase awareness of safe working practices in the masonry industry.

 Statistics indicate that the most common injuries are slips and falls. Over 50% of these injuries occur because of improper scaffold practices. The information presented here deals with site preparation, mudsills, baseplates and leveling screws.

Site Inspection

Check location for

  • ground conditions
  • overhead wires
  • obstructions
  • change in surface elevation

Site Preparation

  • Soil must be level and firm
  • Mud and soft soil should be replaced with compacted gravel or crushed stone
  • Where mudsills must be placed on sloping ground, the area should be leveled, if possible, by excavating rather than by backfilling.
  • Clear ice and snow before placing mudsills
Illustration showing improper site preparation
Illustration showing proper site preparation

Sections 128 (1)c of the Construction regulations require that every scaffold have footings, sills or supports that are sound, rigid and capable of supporting twice the maximum load to which the scaffold may be subjected without settlement or deformation.


  • Use 2" x 10" planks for mudsills.
  • Lay Planks under at least two supports, either along the scaffold or across its width.
  • Center scaffold baseplates on the mudsill and extend mudsills two feet past the last scaffold frame.
  • Use leveling screws to compensate for uneven ground and to ensure that scaffold is level and plumb.


Distribute weight on mudsill and prolong plank life.

Attach scaffold to mudsill and prevent movement due to impact, vibration or uplift due to improper loading.

Leveling Screws

Eliminate need for blocking under mudsill.
Allow for easy leveling and plumbing of scaffold.

Leveling screws can be adjusted up or down so that the scaffold sits level. Be careful not to overextend screws.

Unsafe Practices


Refresher Quiz - Answer True or False

1. Baseplates should be centered on and nailed to mudsills (T/F)
2. Mudsills should never extend beyond end of scaffold. (T/F)
3. For minor adjustments to plumb, use leveling screws. (T/F)

Answers are at the bottom of the page.

For more information and training call:
© Construction Safety Association of Ontario
21 Voyageur Court South, Etobicoke, Ontario M9W 5M7


Medical Device Reprocessing Association of Ontario

MDRAO, Box 225 Timmins, Ontario P4N 7C9

Fax: 705-268-4421

Updated: 3/14/2016

Answers: 1) true 2) false 3) true