What is stucco?

Stucco is defined by Webster as plaster or cement for covering walls. Stucco systems for exterior applications are made of portland cement. So a Western 1-Kote System is stucco. A conventional wall system consisting of a scratch and brown coat of portland cement is also stucco. Walls systems that are composed of foam, resins and fiberglass (like EIFS) are not stucco.

What is the difference between one coat stucco and conventional stucco?

Conventional stucco is two-coats of portland cement plaster (TOP GUN) over lath. The first coat is the scratch coat and called so because it is literally scratched with a tool, to leave long horizontal ridges that provide a mechanical key for the next coat. The brown coat (or second coat) brings the wall out to a level surface and usually to a full ¾" thickness. A finish coat is applied over the brown coat.

A one-coat system (Western 1-Kote) is a modified portland cement plaster that is designed to go on in one coat from 3/8'to ½" in thickness. A finish coat is applied over the top. One-coat systems are often applied over insulating foam.

If it requires two coats, why is it called Western 1-Kote?

Originally the color was added to the one coat plaster and it was a one coat system. Because Western 1-Kote is mixed with various types of bulk sands, on the jobsite, the true one coat system provided unreliable color and the fibers used to strengthen the mix often were visible on the surface. A two coat application is a far better system for color, crack bridging and overall aesthetics.

If one coat systems use insulating foam- how does Western 1-Kote differ from Exterior Insulating Finish Systems (EIFS)?

ONE - Exterior Insulating finish Systems use lower density foam than one coat systems and do not use metal reinforcing to hold the material in place. Western 1-Kote is a portland cement product; EIFS is not.

TWO - Portland cement systems are 'water managed systems' - meaning a system of flashings, screeds and weather barriers are used to drain water. Residential EIFS walls are forced by new building codes to provide drainage planes (that is very high priced) but commercial EIFS is not. Commercial EIFS are barrier systems that trap water when sealant joints breakdown. Portland cement systems are also more impact resistant. EIFS should not be used in high traffic areas.

Am I required to “disclose” information about the stucco on my house when I sell it?

NO! There are no special regulations or insurance limitations on Western 1-Kote or any stucco system. EIFS may require special insurance programs. Many insurance companies now exclude EIFS from coverage. If you elect to use EIFS, check with your applicator to see if they are insured or if you are required to make any disclosures.

Is three-coat stucco (conventional stucco) considered 'traditional' stucco?

I suppose at one time it was. However; today the largest housing markets in the country use one coat stucco systems. In fact, over the last 20 years one-coat stucco has become the 'traditional' stucco system for residential construction. It is also used a great deal for commercial construction.

How long does stucco last?

As far as I can tell: forever. I have seen thousands of yards of conventional stucco over 50 years old and thousands of yards of one coat stucco older than 20 years. Certainly finishes flake, peel, crack and discolor but the stucco wall – the wire and portland cement - go on and on.

What are the most common complaints with stucco systems?

Hairline cracks, leaks and efflorescence.

I want the best stucco job I can get. What should I have my plastering contractor do to avoid problems?

A – Cure the walls. Cure stucco walls for at least 3 days by spraying with water. In hot climates, cure early in the morning and late in the evening, so walls have the maximum time to utilize the moisture.

B- Use Z-metals with end dams over any penetration in the wall (windows, doors, and vents.) This is simple, cheap and very effective for preventing water leaks.

C- Use textured acrylic finishes (PAF-e) to provide an attractive exterior finish with good crack bridging characteristics.

What finishes should I use over my stucco system?

In order to properly finish a stucco wall both texture and color need to be applied. Texture and color may be applied in one step with products like (Western Exterior Stucco) or (PAF-e) – or in two steps with (Paint Base Stucco) for texture then exterior grade paint of all types for the color.

If I elect to use a paint coating, what should I look for?

Paints should be a good quality acrylic product or an elastomeric. Stucco walls are high in pH that can be very detrimental to paint coatings. All the major paint manufacturers have products specifically designed for stucco. Normally they specify a paint 'system' consisting of an alkali resistant primer then the final coating. Both coatings are usually called out to be applied at a specific minimum thickness. For the best job make sure the painter utilizes one of these systems and follows the manufacturers instructions.

What are the differences between textured acrylic finishes (PAF-e) and Western Exterior Stucco?

Western Exterior Stucco is a portland cement and lime mix with pigments added for color. It is available in a wide variety of colors; although light and muted colors work better with this product. Western Exterior Stucco adds real depth and dimension to walls. It is the only product that combines the effects of texture, color and light. It is an excellent choice for southwest stucco designs. Because it does combine texture, color and light - it is not consistent in color like paint and can be unpredictable in terms of the finished 'color.' Western Exterior Stucco is very poor at bridging cracks. So tolerance of hairline (or sometimes larger) cracks are required.

Premium Acrylic Finish e Formula (PAF-e) is an acrylic based resin with high grade aggregates designed to express specific textures when applied to stucco surfaces. PAF-e is available in a wide range of colors from muted to saturated. The textures available with PAF-e look very much like Western Exterior Stucco but the product is far superior to exterior stucco at bridging hairline cracks. It is also water resistant and less prone to efflorescence.

I like the look of Exterior Stucco instead of acrylic based finishes. What should I do to get the best Exterior Stucco Finish?

Weather, color and your expectations about cracks are important considerations. In climates subject to heavy rains and wind-driven moisture, lighter colors are preferable due to the likelihood of efflorescence. (See photo) Exterior Stucco does not have much in the way of crack bridging ability, so walls should be given the maximum waiting period before application of the finish over the brown coat: Twenty-eight days is suggested. Hairline cracks should be expected and will occur. Finally do not specify smooth finishes unless you are willing to live with hairline cracks that are highly visible. (See photo)

Is there an organization that can provide good information about the stucco industry?

The best organization in the West is the Northwest Wall and Ceiling Bureau. www.nwcb.org

Are there any good publications about stucco?


The Consumers Stucco Handbook
By: John Bucholtz
Plaster Information Center
1745 Saratoga Ave. Suite A
San Jose CA 95129
(408) 2572444
Email to stuccoguru@sbcglobal.net

Plaster Textures Brochure
2286 N. State College Blvd.
Fullerton, CA  92831