Plaster cracks form when a stronger force exceeds the restraint capacity of the stucco system. Cracks are "stress-related" energy. Some examples of stress related energy are settlement, wind load, seismic movement, impact from shutting doors, windows, hammering on the interior walls and shrinkage from drying.

It is the nature of stucco to experience some cracking, small cracks that are up to 1/8" are normal and/or within the industry standards. These cracks are only cosmetic and not a result of a structural problem in the stucco system of your home and do not require any maintenance or repair. Small cracks will not accept material, and the resulting patch will detract from the natural beauty of the stucco and will serve no useful purpose. In most cases, an attempt to repair these cracks results in a patch that shows worse than the original crack. Do not put caulking into cracks.

Certain fine or smooth textures accentuate cracks where even check cracking is more visible. Heavier textures tend to hide stucco cracks. Cracks can occur in stucco regardless of texture though. If you experience cracks that are over 1/8 inch in width, you should contact your builder so that the proper resolution can be determined.

Stucco Cleaning
Stucco should be cleaned and inspected annually. Stucco can be cleaned with water, a brush and mild detergent. Each year stucco surfaces should be inspected for any holes, significant cracks or separations. If stucco repairs are needed, it is important that such repairs be completed on a timely basis before damage can be incurred to your home.

Maintenance
Stucco requires certain maintenance items to be completed to ensure that the stucco will perform properly. Stucco cracks. It is the nature of stucco to experience some cracking. Small stucco cracks are normal and do not require any maintenance or repair. If a crack exceeds 1/8 inch in width then the crack should be repaired. Repairing of stucco cracks is made by adding a small amount of stucco to the crack. Do not put caulking into cracks. If you experience cracks that are over 1/8 inch in width, you should contact your builder so that the proper resolution can be determined.

Items That Can Cause Stucco Damage

1. Improper clearance between weep screeds and the finished grade. The metal weep screed installed around the bottom of your home is to allow any water that gets past the stucco to safely exit. There should be a minimum clearance of 4 inches between the weep screed and the finished grade. If concrete walkways or some other hard surface is installed up to the foundation of your home, there should be a minimum clearance of 2 inches between the weep screed and such concrete or hard surface. Care should be taken to ensure that weep screeds are not covered by landscaping or concrete walkways.
2. Attaching items to stucco walls. The stucco on your home has been installed to stop water from penetrating into the wall. If incidental water does enter through the stucco, there is a weather resistant membrane (black paper) that has been installed behind the stucco. It is essential not to penetrate the stucco wall or the weather resistant membrane with nails, screws, staples or any other fastener. If it becomes necessary to mount something to the stucco walls, a professional craftsman should be hired in order to ensure that the proper fasteners and sealant are used.
3. Sprinkler systems directed toward your home. Sprinkler systems should direct water away from the stucco walls of your home. The continual spaying of water onto stucco walls can cause damage to the stucco, damage to weep screeds, create stains and allow green algae to grow on stucco walls.
4. Improper Slope of Finished Grades. The area around your home should slope or drain away from your home at a 2% slope or more. You should be careful when doing any landscaping work to ensure the slope of your finished grade is not altered. If the finished grade drains back into the home it can cause water to seep under the foundation. Wet soil can swell and expand which can lift up your home, causing damage to the stucco as well as other areas of your home.
5. Damaged Foam Projections. Foam projections should be treated with care. Foam projections (add-ons) are purely decorative and should not be used to support flower pots, or to climb or stand on. When using a ladder, care should be taken not to make marks in foam projections. Ladders should not be placed against the stucco without soft foam guards placed over their ends. Unprotected ladders can scar or otherwise damage the stucco walls. Ladders should never be placed on or touch foam details. Foam details could be dented, punctured, or scared by placing or leaning ladders against them. The damages caused by abuse include: stucco chipping off, detail ripping off wall and holes being punctured in detail.
6. Additions to your home. Adding on to your home or attaching a sun screen or patio cover must be done by a professional craftsman using proper materials and procedures. Otherwise you can damage your stucco system and void your warranty. Cen Cal Plastering, Inc would be happy to give you an estimate if you decide to make additions to your home.

Items That Require Maintenance

1. Windows, doors and other wall penetrations. Where stucco meets a window, door, electrical box, dryer vent or any other wall penetration you may notice a small expansion gap. Gaps are normal and should be expected since dissimilar materials will expand and contract at different rates thus causing slight separations. Such gaps can allow excessive amounts of water to get past the stucco and therefore should be caulked at least on an annual basis. The best method is to obtain a quality tube of caulking (25 year) from your local hardware store and squeeze the caulk directly into any gaps. You can use your finger or a putty knife to ensure that the caulking is pushed into the gaps.
2. Window weep holes. At the bottom of each windowsill you will find several small holes that allow water to exit from the windowsill track. With the passage of time, dirt, leaves or other items can clog these weep holes causing the water in the windowsill to leak over the windowsill track into the home. When you first move into your new home all window weep holes should be carefully inspected to ensure that they are clean. Sometimes during construction window weep holes can be filled with stucco, paint, or other construction debris. Cleaning window weep holes can be easily performed with any small sharp object such as a pen or an extended paper clip.
3. Gutters and downspouts need to be kept clean so the water flow is not obstructed. Any defects in these items should be repaired promptly. These can be sources of water entry into the structure.
4. Stucco. Exterior Stucco should be cleaned and inspected annually. Remove soil as soon as possible. Exposure to repeated mud splashes, especially with clay based soils can cause staining. Remove soil as soon as possible. Exposure to repeated mud splashes, especially with clay based soils can cause staining. Stucco can be cleaned with a mild soap and water and plastic brush, never a metal brush. Window cleaning solutions should be rinsed off stucco and not left to dry on stucco surface. Mold, mildew, and algae can grow on virtually any surface if the conditions are right. If these appear on the surface of the exterior stucco, it should be cleaned and removed. A solution of one part household liquid bleach and five parts water can be used with a plastic brush. If you are unsure of the results of this method, test a small area first. Each year stucco surfaces should be inspected for any holes, significant cracks or separations. Any damage you may find needs to be repaired in a timely manner, otherwise more damage can be incurred. If stucco repairs are needed, it is important that such repairs be completed on a timely basis by a qualified stucco craftsman before damage can be incurred to your home.