Weather-Related Causes of Paint Failures on Stucco Exterior Walls
STUCCO WAll FAILURES DUE TO WEATHER - CONTENTS: Stucco wall paint failures caused by weather conditions. Too hot, too cold, too dry, too wet, too windy, too sunny: conditions affecting the success of a stucco exterior wall application. Stucco exterior cracks, white deposits, stains, efflorescence causes. The role of weather conditions in the success or failure of exterior stucco jobs
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Weather-caused stucco wall coating or paint failures:
This article reviews common weather-related causes of exterior stucco problems and failures when installing modern stucco or EIFS building exteriors.
We include photographs of weather-related stucco failures on buildings useful to assist in diagnosing the probable cause of stucco wall coating failures such as stains, efflorescence, blotching, cracks, and leaks.
Water & Weather Impact on Inspection of Painted Stucco Surfaces
The diagnosis and cure of paint failure on
buildings, particularly on wood siding and trim, is quite possible if there
is a careful and thorough inspection of the building, its history, its surfaces, and the actual points of paint
It is diagnostic to compare the same coating on the same type of surface at different
locations on a building and in areas of failed and not-failed paint.
[Click to enlarge any image]
Water or wet stucco combined with high pH is the problem. It is the combination of painting over a still-wet stucco surface or still damp surface, or a surface that is subsequently exposed to abnormal wetting, along with high alkalinity that causes saponification of an acrylic paint on stucco.
When painting a sufficiently dry stucco surface, alkalinity alone will not cause this problem. - paraphrased from KTA Tator, a Pittsburgh consulting firm.
As our photo demonstrate, the appearance of any painted surface, particularly new stucco, can be significantly different when it is wet.
While there is nothing abnormal or "wrong" with a painted surface that looks a bit different when wet, say darker in color, streaks or the appearance of mottled efflorescence or white blooms on a wall after wetting may be telltales of a paint problem, and certainly these inconsistencies mean that a paint failure investigator needs to inspect when the surface is dry. Inspecting in the rain or just after raining or other sources of wet on a building exterior may lead to incorrect conclusions.
White Run-Down Stains on Exterior Stucco after New Paint Job
Below we show several photographs of ugly white stains that appeared quickly after a reader's home's stucco exterior was spray painted in 2010.
The reader indicated that the painters applied a Dunn-Edwards exterior flat acrylic paint very quickly, perhaps too quickly, after the home had been power-washed. The stains are most likely not due to a defect in the paint itself (unless it was amended or over-thinned by the painter) and more likely due to improper surface preparation combined with painting before the surface was dry after power washing.
The Importance of Weather to Stucco Work and Stucco Paint Coatings
Moisture, humidity, rain, or wet conditions during thin-coat or EIFS stucco work can lead to a subsequent series of failures of the entire installation. The home shown in our photo (left) was the subject of litigation. We observed that the final stucco had been applied over wet surfaces and in some cases over surfaces that also had been troubled by soil that had splashed-up on the building during rainy weather.
Temperature during stucco work will speed up or slow down the
hydration process that cures the cement in stucco. It is best
to avoid application in extremely hot or cold temperatures.
In hot, dry, and windy weather, frequent misting will be
required on the scratch coat or the installer may need to
tape polyethylene sheeting in place for proper curing.
Direct sun tends to dry out the fresh stucco too fast, so
installers should try to follow the shade around the building.
Also, retardants are available that can be sprayed on
the scratch or brown coat in hot weather to slow down the
Sun, heat, and rapid drying conditions can present special stucco application troubles or subsequent stucco paint coating troubles in hot dry climates such as the American Southwest. (Photo at left).
Cold weather also presents problems. Stucco should
not be applied under 40°F, and it should not be allowed to
freeze within 24 hours of application. Accelerators can
be added to the stucco mix in cold weather, but these
can weaken the material, and calcium-based accelerators
can lead to efflorescence.
Heating the materials and, if necessary,
tenting the structure can permit work to proceed in
cold, even freezing, weather.
Cool, moist weather is ideal for traditional stucco wall installations. In humid weather, with
relative humidity over 70% or heavy fog, misting is not
See details about the cause, diagnosis, cure, or prevention of paint failures on stucco exterior walls, found at STUCCO PAINT FAILURES.
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All surfaces must be cured, clean, dry, and free from dirt, dust, rust, stains,
grease, oil, mildew, wax, efflorescence and other contaminants. Remove all
loose, peeling, or chalky paint by sanding, scraping, high-pressure washing
or other appropriate methods. Repair all cracks, holes, and other surface
imperfections with a suitable patching material. Repaired surfaces should
match the surrounding surface texture. If efflorescence exists, remove all
noticeable deposits and prime the entire surface with Super-Loc® (W 718),
Eff-Stop® (W 709) or Acri-Loc® (W 6232).
 KTA-Tator, Inc.,
115 Technology Drive,
Pittsburgh, PA 15275,
E-mail: email@example.com KTA is a Consulting/Engineering firm founded in 1949 in Pittsburgh, Pennsylvania. Their main specialty is consulting and inspection in the protective coatings and construction industries.
Painting Contractor Newsletter on Alkalinity and Efflorescence in New Stucco, The Paint Quality Institute, in which the authors point out that high pH and efflorescence correlate. This article suggests that the painter should use a water-based primer/sealer, (Scott Paint recommends an acrylic stucco primer) then use an alkaline resistant 100% acrylic latex top coat, avoid bright colors, and apply two top coats to be sure that cracks and pinholes are sealed. The Paint Quality Institute is at PO Box 904, Spring House PA 19477. www.paintquality.com
 Paint and Surface Coatings, Theory and Practice [purchase at Amazon.com], R. Lambourne & T.A. Strivens, Ed., Woodhead Publishing Ltd., William Andrew Publishing, 1999 ISBN 1-85573-348 X & 1-884207-73-1 [This is perhaps the leading reference on modern paints and coatings, but is a difficult text to obtain, and is a bit short on field investigation methods - DF]
 Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: firstname.lastname@example.org
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
 Why House Paint Fails [on file as /exterior/Why_House_Paint_Fails_FPL1.pdf ] - , Mark Knaebe, US FPL, web search August 2010, original source: http://www.fpl.fs.fed.us/documnts/finlines/knaeb95a.pdf
 Why Paint Jobs Fail [on file as /exterior/Why_Paint_Fails_Bennett.pdf ] - , web search, August 2010, original source: http://www.bennette.com/pdf/whyfail.pdf, four pages describing alligatoring, bleeding, blistering, etc. Bennette Corporation, P.O. Box 9088, Hampton, VA 23670, Phone: 757-838-7777, Toll Free: 800-869-2929
Fax: 757-827-0529, Email: email@example.com, Website: www.bennette.com quoting: Bennette Paint Manufacturing Company, Inc. is a Virginia corporation which was founded in Newport News, Virginia in 1966 by James P. Bennette, Sr. In 1984, Mr Bennette sold the company to his employees through an Employee Stock Ownership Plan (ESOP). Today the company has a modern manufacturing plant, research laboratory, central warehouse and general offices located at 401 Industry Drive, Hampton, Virginia. From these facilities the company is able to supply quality paints and coatings through its company owned distribution and service centers and authorized dealers located in Virginia, North Carolina and South Carolina. Bennette Paint Manufacturing Company, Inc. also owns and operates Bennette Equipment Company which specializes in the sale, service, and rental of paint spraying and pressure cleaning equipment.
 Supplemental Guidelines for Removing Paint From Interior and Exterior Wood Surfaces [on file as "/exterior/Paint_Removal_USGSA.pdf ] - , US General Services Administration, Historical Preservation Technical Procedures, 06400-02, web search August 2010, original source: //w3.gsa.gov/web/p/Hptp.nsf/0/40aff5a115b6a9e5852565c50054b4f4?OpenDocument
 "Staining and Microbiological Infestation of Acrylic Paintings on Hardboard", Ulrik Runeberg, Conservator (Dipl. Rest./M.A.), Museo de Arte Contemporáneo de Puerto Rico, San Juan Presented,April 2007 conference in Richmond Virginia, sponsored by the AIC (American Institute for Conservation), this paper discussed the staining and microbial infestation of acrylic paintings on hardboard. - private correspondence, ER <->DF 12 September 2006. The following quotation is from the paper's abstract:
"Hardboard served as a common and popular support for many modern paintings that were carried out from the mid - 1920’s, and still is used occasionally in contemporary art. Many artists rejected hardboard as an inferior industrial construction material of low aesthetical value, whereas others considered the processed and compressed wood fiber boards to be a stable, light and economic alternative to solid wood panels and other rigid supports.
"From the conservator’s critical point of view, the many disadvantages of this type of support include: high acidity, hygroscope characteristics, tendency of ‘off-gassing’, (>tendency of) warping, occasional flaking of painting material in the case of tempered hardboard. The deterioration of paintings on hardboard depends on a number of factors including: the quality of the hardboard, prevailing storage conditions, and the preparation of the support by the artist. While there are many paintings on hardboard that are in very good condition, this paper will focus on those paintings that are heavily deteriorated and damaged.
"A very characteristic damage found on porous painting layers such as acrylic colour on hardboard, is the formation of stains. Generally, those stains are described without any differentiation as ‘fox-spots’. The examination of various paintings concerned led to the conclusion, that there exist different kinds of stains that need to be discriminated against each other, to ensure an appropriate conservation and restoration treatment.
"This paper aims to characterize and differentiate the stains, and will provide preventive and practical treatment proposals for the conservation and restoration of affected paintings. Questions such as ‘What are the stains composed of?’ and ‘Which may be the causes?’ will be addressed. Stains may consist of a variety of contents, such as: Ligneous residues, fungal infestation, bacterial activity, a combination of microbial and support induced discolouration [SID], a ‘symbiotic relation’ of ‘SID’ and fungal infestation, or the blooming of ingredients from the original painting materials. A range of microscopic analysis of the actual microbiological infestation of selected samples will be provided. The paintings that were examined, sampled and treated, are part of the Puerto Rican heritage, and were all kept in excessive humid tropical conditions, before they entered the Conservation Department of the Museum of Contemporary Art in Puerto Rico.
"Conservation treatment options of stained paintings on hardboard will be discussed. A high level of acidity (caused from SID and/or micro-organisms) may require measures of reduction, disinfection and neutralization. Treatment methods that reduce the ligneous stains and residues of micro-organisms, and neutralize affected areas in painting layers include stain removal through the application of soaking compresses (poultices), and de-acidification through alkaline material.
"Other aspects of deterioration, that do not have to do directly with the formation of stains, but also are typical for hardboard as painting support, will be mentioned briefly." - U.R.
 Thanks to reader Christa for discussing white staining on an exterior stucco wall and for providing paint stain failure photographs. May 2010
 Wall Systems, 217 Kinley Ave., NW, Albuquerque, NM 87102 Tel: (505) 242-WALL (9255) and Wall Systems, Inc., 5000 E. Nebraska, Tucson, AZ 87706, Tel: (505) 574-2379 - a Stucco & Sto-Wall contractor has provided contact information for readers needing services in the Southwest: Tel: 505-242-WALL. Website: http://www.albuquerquestucco.com/
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
Analysis of Modern Paints, Thomas J.S. Learner, Research in Conservation, 2004 ISBN 0-89236-779-2 [Chemistry of modern paints, overview of analytical methods, pyrolysis-gas chromatography signatures of basic modern paints and their constituents, Fourier transform infrared spectroscopy for paint analysis, direct temperature-resolved mass spectrometry, and analysis in practice - technical reference useful for forensic paint science, focused on art works -DF]
Paint and Surface Coatings, Theory and Practice [purchase at Amazon.com], R. Lambourne & T.A. Strivens, Ed., Woodhead Publishing Ltd., William Andrew Publishing, 1999 ISBN 1-85573-348 X & 1-884207-73-1 [This is perhaps the leading reference on modern paints and coatings, but is a difficult text to obtain, and is a bit short on field investigation methods - DF]
Paint Handbook: testing, selection, application, troubleshooting, surface preparation, etc., Guy E. Weismantel, Ed., McGraw Hill Book Company, 1981, ISBN-10: 0070690618, ISBN-13: 978-0070690615, [Excellent but a bit obsolete paint theory and practice, also a bit light on field investigation methods, out of print, available used-DF] How to select and apply the right paint or coating for any surface. The first major reference to help you choose the correct paint or other finish to do the job best on a particular surface exposed to a particular environment. Experts in the field give full advice on testing surface preparation, application, corrosion prevention, and troubleshooting. The handbook covers wood, metal, composites, and masonry, as well as marine applications and roof coatings. A ``must'' working tool for contractors, architects, engineers, specification writers, and paint dealers.
Paint and Surface Coatings, Theory and Practice, R. Lambourne & T.A. Strivens, Ed., Woodhead Publishing Ltd., William Andrew Publishing, 1999 ISBN 1-85573-348 X & 1-884207-73-1 [This is perhaps the leading reference on modern paints and coatings, but is a difficult text to obtain, and is a bit short on field investigation methods - DF] Provides a comprehensive reference source for all those in the paint industry, paint manufacturers and raw materials suppliers, undergraduate and postgraduate students, and industrial paint users. R. Lambourne was in the Research Department at ICI Paints Division and the Industrial Colloid Advisory Group, Birstol University, UK.
Sealants, Durability of Building Sealants (RILEM Proceedings), J.C. Beech, A.T. Wolf, Spon Press; illustrated edition (1995), ISBN-10: 0419210709, ISBN-13: 978-0419210702 This book presents the papers given at the RILEM Seminar held at the Building Research Establishment, Garston, UK in October 1994. The book provides an opportunity for researchers to review up-to-date progress towards the achievement of the objectives of the standardisation of laboratory techniques of sealants in the variety of service conditions to which they are exposed.
"Moisture Control in buildings: Putting Building Science in Green Building," Alex Wilson, Environmental Building News, Vol. 12. No. 5. [Good tutorial, "Moisture 101" outlining the physics of moisture movement in buildings and a good but incomplete list of general suggestions for moisture control - inadequate attention given to exterior conditions such as roof and surface drainage defects which are among the most-common sources of building moisture and water entry.--DJF]