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Hello Reggie

I live in San Luis Obispo County in California and code is 7 days between the brown coat to sit before a finish is applied. We still think that is too short. We give custom homes at least 3 weeks.

We double spread a 20/30 base to create a smooth coat finish. We get a lot of cracks. I know its probably from the thickness of the material. The house usually get a coat of elastomeric paint which fills in most of the cracks. Do you have any suggestions on creating a smooth coat finish without the cracks?

Thank you for your time and I enjoy your website.

Here is a 14 year old video I took using a flip phone. I am saying "This is our version of a California-style mission finish." The finish is troweled smooth, but isn't nearly as smooth as interior plaster. Sand and cement don't work the same way as inside plaster. This is my favorite stucco finish. Here, we are using color from Expo stucco (now defunct) in San Diego:

I think I found the solution to reducing cracks, from no cracks, to at least very few cracks on a smooth troweled mission finish. We stuccoed a big stable here in Virginia for a woman from San Francisco that wanted a smooth troweled, also called a steel troweled or mission finish like her house in San Jose. We had right many cracks, but she expected it. We used real fine sand and water troweled the wall which caused more shrinkage. We have done smooth troweled stucco finishes over the years.

We stuccoed a house for a guy who lived in Italy for years and loved that smooth troweled mission finish. There weren't any cracks the last time I went up there, so I doubt there are many now. The house is on ICF, that is insulated concrete forms, and not wood framing, but the cracks you are getting are mainly from shrinkage.

Here is a link to my job with a mission finish:

Scroll to New stucco house in Bentonville, Virginia

One thing is that premixed stucco finishes like La Habra and El Rey have way too much lime. Too much lime causes shrinkage cracks. Our formula is 1 94 bag portland: 1/4 bag (50 lb.) lime, a 2 100 lb. bags white silica sand. You can use you California color packs 3 to a bag of white portland. Instead of 3 packs to 3 90 lb. bags, 3 packs to 312 pounds of material. Your color will come out the same.

The biggest thing to reduce cracks in the finish is a chemical bonding admixture in the finish. We use flex-con, but there are other brands like acryl 60. This is mixed half admixture and half water. The admixture will eliminate your shrinkage cracks. It isn't cheap but it works. A bucket of flexcon cost about 90 dollars. Mixed half and half with water should make almost two bags of white portland.

20/30 sand ratio is a mix of medium and fine, with 16/20 being coarser, or a mix of coarse and medium. The sand we use is graded differently. The sand I use sometimes for my stucco finish is screened crushed quartz from US Silica, called Q-ROK. Q-ROK isn't sold anymore in the Washington, DC area anymore, so I have to go a long way to get it. Fine is No. 1, medium is no. 2, and coarse is no. 3. We usually mix 2 and 3 together, or 1 and 2 together.

In Bentonville, I used pure medium sand, that is no. 2. You may call this a 20/20 finish. I found that the finish laid nice and flat, and was excellent for a mission finish, which usually looks a little bumpy.

So great to hear from you.