Next comes the scratch coat, which is a base layer of field-mixed Portland cement, sand, lime, and water with a series of horizontal lines scratched into it. Then comes the brown coat. This layer is applied with a darby, or long trowel, to make sure the cement is applied evenly.

What is the purpose of a scratch coat?

Characteristics: The surface is very rough with horizontal lines running through it which are made from a scarifier (aka scratcher) tool. The scratch coat allows the next coat (brown) to be applied over it and the roughness provides a great mechanical bond, on top of the chemical bond that takes place as well.

How thick should a scratch coat be for stucco?

The scratch coat should be 3/8″ thick. Force it through the wire mesh so that it fills the ¼” gap between the mesh and wall completely. 3. Smooth the scratch coat with the trowel.

What is the difference between scratch coat and brown coat?

Scratch coats are mixed at 1 part cement to 2-1/4 to 4 parts sand, brown coats are mixed at 1 part cement to 3 to 5 parts sand, and finish coats are 1 part cement to 1-1/2 to 3 parts sand.

What is scratch and brown stucco?

• SPEC MIX® Scratch and Brown Preblended Stucco is a dry, preblended cement-based product designed to be used as the scratch and/or brown coat in a three-coat stucco application. This product also can be used as the first coat in a two-coat application for exterior stucco applications.

How long do you leave a scratch coat?

The first coat is known as the scratch coat, and is applied in a thin layer and left to cure. This can take from between 24 hours up to two days, depending on humidity, temperature, and airflow around the building.

Is scratch coat necessary?

Step 3: Scratch Coat A scratch coat will be needed when metal lath is used. This step is not necessary when applying stone veneer to a cleaned concrete, masonry, or stucco surface.

Is it normal for the brown coat of stucco to crack?

Application of the brown coat before the scratch coat has properly cured, and failure to make the additional trowel‐float pass, are common causes of cracking in the finished stucco. The finish coat may be either Portland cement plaster or acrylic, typically 1/8‐in.

What are the different types of stucco finishes?

• Dash Finish (Roughcast Style) …
• Cat Face Finish (Known Also as Montalvo or California) …
• Sand Finish (A Style that Floats) …
• Spanish Lace Finish (Grace and Elegance) …
• Santa Barbara Finish (Soft and Soothing) …
• Worm Finish (Get Your Groove On)

Does stucco need a finish coat?

Stucco application typically requires three coats. The initial “scratch coat” provides adhesion to the building. The “brown coat”, which comes second, is responsible for creating an even surface. Finally, the “finish coat” determines the stucco’s outward appearance.

Article first time published on

How much does it cost to stucco a $3000 square foot house?

Home SizeAverage CostTypical Range3,000 square feet$13,500$9,000-$18,0005,000 square feet$22,500$15,000-$30,000

Why is the second coat of stucco called the brown coat?

The “scratch coat” step is so-named because the first layer of stucco is scratched with trowels to provide a key for the second layer. … This step is called “brown coat” because it is traditionally made with sand and cement.

What kind of cement do you use for stucco scratch coat?

QUIKRETE® Scratch and Brown Base Coat Stucco (No. 1139) is a portland cement based stucco used for construction and repair of stucco walls. Complies with ASTM C 926 requirements for cement based plaster.

How thick is stucco finish coat?

Although it is called a “One Coat System,” the stucco material is usually a 3/8 inch thick coat with a 1/8 inch finish coat applied over it; thus two layers or coats.

What is color coat stucco?

Merlex Exterior Stucco is a premium quality portland cement based color coat finish material specifically intended for use as a decorative finish over properly prepared portland cement based substrates. … Standard colors or custom matches available upon request. Eliminates the necessity for painting.

Do you need a scratch coat on a concrete wall?

Usually you won’t need to apply a scratch coat to a cinder block or cmu wall but in some instances like installing stone veneer, you will need a good base for the material to stick and a scratch coat is perfect.

What is lath and scratch?

In industry terms — lath, scratch and brown. … More specifically, a lath of an asphalt-infused paper is applied over a weather-resistant barrier. Then a layer of furred chicken wire (meaning it sticks off the wall a little bit) is applied.

What is scratch plaster?

Scratch Plaster is a premium, robust, aesthetic, finish, ideal for large scale commercial, retail and civic buildings. It has a pitted, striated pattern of scratch indentations in 4 looks: fine, extra fine, pronounced and extra pronounced. The product can be very successfully tinted in customised colours.

What is a concrete scratch coat?

Scratch coats are particularly important in the world of vertical decorative concrete. … With an aggressive scratch coat, not only do you have a chemical bond but you also have a mechanical bond and this is key for thick applications of vertical decorative concrete mixes.

Do you wet scratch coat?

Only wet the walls down if they are porous – do a suction test by putting a small amount of render on the wall – if it starts to firm up in a few minutes then you may need to damp down, but it will stick without this if they are not too porous.

How do you make a scratch coat moist?

At a minimum, mist the scratch and brown coats at the start and again at the end of each calendar day.) If there is a delay before applying the brown coat, moist-cure the scratch coat daily until the brown coat is applied. Moist-cure the brown coat for a minimum of two consecutive days.

How wet should scratch coat be?

The surface of the scratch coat must be hard but still moist to ensure the full strength of the coat is achieved and the next layer will adhere properly. Applying a second coat later requires that you mist or spray the walls with water to keep moisture in. Fog spraying is one way to ensure proper hydration.

How do you finish a stucco coat?

1. 1 part Portland cement.
2. ​1 part ​hydrated lime.
3. ​3 parts ​sand.
4. ​​Water to thin out mix to a cake batter consistency.

What is stucco finish?

What Is a Stucco Finish? Stucco itself is a cement-type mixture made of sand, Portland cement, lime, and water. Stucco is considered a thin finish coat, the outermost layer that is visible and can be painted. To make stucco work, you need layers below it to provide an adequate base.

What is a stucco dash coat?

Re-dash consists of a single layer of the Portland cement, with colorant applied to cover and freshen the surface. Repairs are made to cracks and minor imperfections in the surface and then the new coat is applied. This will provide a new look and keep with the integrity of the existing finish.

What is smooth stucco finish?

A smooth stucco finish, also known as a fine cement based finish, is one of the most difficult textures to achieve and is also the most popular among homeowners because it’s easiest to clean and offers a finish closest to looking like a painted home.

Can new stucco be applied over old stucco?

You can apply new stucco on top of old, so long as the proper measures are taken to ensure the integrity of the new layer. Check the existing stucco for structural integrity. … Keep the nozzle at least two feet from the surface of the stucco area. Allow 48 to 72 hours for the stucco to dry.

When should I be concerned about stucco cracks?

Larger cracks, we’re talking 1/16 of an inch, are cause for concern. If you can slide your credit card into the crack in your stucco, it’s time to seek some professional help. Larger cracks like these can indicate a structural issue that needs to be addressed prior to repairing the stucco.

How much does it cost to stucco and paint a house?

National average cost$5,000Minimum cost$1,400Maximum cost$19,500Average cost range$2,400 to $8,100

Why you should not paint stucco?

Stucco needs to breath – One of the main reasons you shouldn’t coat your stucco with paint is because stucco is porous. This allows moisture that hits the surface to easily evaporate away. A coat of paint can harm that breathability.

Is painting stucco a bad idea?

It provides an attractive look and effectively protects your house against the elements. Stucco is mostly low maintenance, but can fade over time, but fret not! It’s paintable with a good result. Here are 5 reasons why painting stucco is a good idea.