What is Spatter Dash and How to Use It for Concrete Plastering

The purpose of Spatter Dash is to prevent rendering and plastering materials from sliding or sagging. A spatter dash's roughness enhances bonding by providing a positive key for the plaster to grab onto. The improper use of spatter dash involves successively bonding rendering to the substrate.

Plastering is accomplished using a key or an even amount of suction. A bonding agent is added to sand, cement, and water. A surface is prepared by throwing spatter dash on it before plastering begins.

A spatter dash is a finish for stucco created by dashing a very thin mixture of cement and coarse sand against a fresh surface. The spatter dash does not have to cover all parts of the surface, and not protecting some parts is in fact beneficial. Surfaces such as scatter dash and pebble dash are achieved by throwing mortar or pebbles on the finish coat while it is still weak.

Construction Process of Spatter Dash

It is essentially a thin, coarse textured coating formed by throwing Portland cement and coarse sand into a target area using a scoop or trowel. Before rendering, this treatment strengthens the bond between the undercoat and the background, enhances the resistance to rain penetration, and smoothes out varying backgrounds' suction.

Coarse sand 8 millimeters and below is dashed roughly on the exterior walling in a mixture of cement in the ratio of 1:1.5 and water equal to .5 parts by volume using this method. Crushed hard stone can also be used in places where sharp sand is not acceptable.

Spatter Dash Workflow

Spatter dash coat mixes should contain 1 part cement and 2 parts coarse sand, diluted with just enough water to form thick slurry, and contain a bonding agent like styrene butadiene rubber. A layer of 3 to 5 mm thick spatter dash should be thrown against the background using a small scoop.

The spatter dash method is the best way to provide coating in the construction. The primary purpose is to create a large number of small lumps of mortar to make the surface as irregular as possible. It is possible to limit the thickness of the spatter dash to 10 mm. Additional work can be performed after two to three days of curing under suitable conditions.

Depending on the type of aggregate, the water content will vary. Water must be slowly added to the dry materials after they have been combined thoroughly. It is necessary to stir the mixture continuously during use.

Exterior Rendering of Buildings

Concrete or clay blocks constructed as exterior walls of buildings are not considered aesthetically pleasing and do not provide attractive appearances. External faces are rendered with lime or cement mixed with natural aggregate and either textured or smooth.

To learn more, watch the following video tutorial.

Video Source: Anime_Edu - Civil Engineering Videos

Rendering also enhances the wall's resistance to rain penetration. A strong bond with the background, the use of mixtures, and the surface finish are also important when it comes to external rendering.

Wrapping it Up

Basically, it is a thin, coarse textured continuous coating formed with Portland cement and coarse sand applied with a trowel, scoop, or other device. It helps bond the undercoat to the background, improves resistance to rain penetration, and evens out variable backgrounds' suction before rendering.

It is necessary to form a large number of small humps of mortar to make the surface as irregular as possible. There may be a limit of 10 mm for the thickness of the spatter dash. Further work can be undertaken after two to three days of good curing. In practically all cases, it is recommended to use the spatter dash method to provide a key for any construction method.

What is Spatter Dash and How to Use It for Concrete Plastering