What are plasterers scratchers used for?

16th March 2020

What are plasterer’s scratchers used for?

			Plasterer’s scratchers are used in various other processes that are similar to plastering .

			As well as different processes, like rendering, there are also different types of plastering that determine when and where the tools are used.

			Scratchers can be used in many of the types of plastering, but are generally for specific stages of these processes.

			Scratchers are used on the under coat of plaster, where more layers are to be applied. They are used to increase the surface area of the plaster, in order to create a better adhesion between layers. This process is called ‘keying in’.

			There are usually no more than three coats (layers) per procedure yet there are many names for various plaster layers. Names for the 1st coat include: scratch, base, pricking-up, dubbing-out, rough and base (and is where these tools are used most). The 2nd coat can be referred to as: brown, levelling and secondary base. The 3rd coat is known as: colour, finish, top and skim.

			Processes similar to plastering
			Rendering Rendering is the same as plastering but on exterior walls and surfaces. It is known as stucco in the US.

			Render is usually applied in layers as in wet plastering (see below). Due to the outdoor factor of rendering, it is important to make sure the surface to be rendered is waterproof, where necessary.

			Types of plastering
			Wet plastering Wet plastering is the process of applying the product(s) straight to the surface (brick, block work) in layers.

			Drywalling Drywall plastering is the use of plasterboard, which is either ‘dabbed’ onto block work with adhesive, or nailed on to studwork. Afterwards, there is usually a skim application of plaster for finishing purposes, however it is possible to tape the joints and apply a decorative finish straight to the boards.

			These tools are more likely to be used in rendering and wet plastering, which involve multi-layer application.