How thick or thin is the stucco?

Look at the trim from left to right.

Before the stucco was applied.

Is it me or cups appear downward, every fastener has torn the single layer of paper and that has to be what installers call the new 1/2 coat system, sure ain’t close to 3/4".

Is that vertical exterior application on gypsum board? Please tell me no.





All pictures of the same house.

It is over the new moisture barrier covered OSB. Another problem in the works.

I haven’t the foggiest clue what we’re supposed to be looking at.

See where the stucco meets the trim in the top of the first picture?

See how thick the trim is?

How thin is the stucco?

If the stucco was applied to the proper thickness of 3/4" minimum for hard coat the 1x4 frieze trim at the soffit should not have a visible reveal the trim would be flush with the stucco surface.

So therefore the stucco is 1/2 inch thick. That much was obvious. I thought there was something wrong somewhere, like the metal lath not being dimpled so that it stands above the sruface, allowing enough stucco to penetrate behind it to achieve a proper bond. If I worried about anything, it would be that.


Other than at the left corner the stucco is doing good to 1/4" thick.


Are you saying this particular installation is acceptable to you and would not get red flagged in your report?

Yet more thin stucco.


I can assure you they have bond.

The pressure they had to apply to get the stucco that thin is more then enough to key it to the lath.

There is probably more stucco on the back side of the lath then there is on the front side.

How can that be the biggest concern?

Depends what was specified. Maybe they got all that they bought. If 3/4-inch was specified, yes, I’d comment on it. But we don’t know what was specified or purchased, do we?

Hi. Richard,

If you don’t mind me saying, whether or not a custom spec was written or not, one would think that at the very least, to expect the Standard Minimum for a Three Coat Stucco Application per National Standards and that a Contractor in Business for such work would be completely abreast in this type of work.

Most specifications would only refer you to the pertinent standards of the ASTM anyways.

There are some basic stucco references that are essential for the designer, the consumer and the applicator.

These references, although few in number, contain a wealth of information necessary for the proper design and the proper application of the product.

• “Portland Cement Plaster (Stucco) Manual” by Portland Cement Association.

• Standard Specification for Application of Portland Cement Based Plaster—ASTM C 926.

• Standard Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster. ASTM C 1063.
• Standard Specification for Surface-Applied Bonding Compounds for Exterior Plastering—ASTM C 932.

Most, if not all building codes express that stucco shall conform to the requirements of ASTM C 926 “Standard Specification for the Application of Portland Cement Based Plaster (Stucco)” and ASTM C 1063 “Standard Specification for the Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster).” Whether one is in California, New York, Texas or Florida, these are the two standards that your code will refer you to.

Over the years, it has been determined that the problem is normally not the materials but the design and application. Of these two items, it seems that there is an equal share of problems. Meaning that there are an equal number of design problems as there are application problems.

To ensure the performance of stucco, it should be designed to meet the national standards as set forth for the proper design and application of stucco. The national model codes all reference ASTM C926 and ASTM C 1063 as the requirements for stucco.

The thickness of stucco on a solid substrate is 5/8 or 1/2 inch. However, on metal base the thickness is 5/8 to 7/8 inch. The additional thickness of stucco on metal base is required to attain the desired hardened cementations properties.
The cost of stucco applied directly to a solid substrate is always less than on a non-solid substrate due to the additional metal base requirement and the additional thickness requirement for stucco on the metal base.

More on this subject :here

Hope this helps some.

Marcel :):smiley: