Scratcher

Definition

A scratcher is any serrated or sharply-tined object used to roughen the surface of one coat of mortar to provide a mechanical key or bond for the next coat.

Purpose

The purpose of a scratcher is to create a rough texture on the surface of mortar or plaster, ensuring that subsequent coats adhere properly and form a strong bond.

Examples of Use

• In plastering, a scratcher is used to roughen the first coat, known as the scratch coat, to help the brown coat adhere.
• Tile installers use scratchers to prepare mortar beds for better bonding of tiles.
• Masonry workers employ scratchers to ensure a good bond between layers of mortar in wall construction.

Related Terms

• Scratch Coat: The first rough coat in a plaster or mortar application.
• Mechanical Key: A textured surface that enhances the bonding of subsequent layers.
• Trowel: A tool used for applying and shaping mortar or plaster.

Notes

Using a scratcher properly is crucial to the success of multi-layer plaster or mortar applications, preventing delamination and ensuring structural integrity.