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Peeling Paint? How to Diagnose, Correct, & Prevent Paint Failure on Buildings InspectAPedia®  -     How to diagnose the cause of failing paint on a building exterior or interior Paint failure diagnosis checklists for the building exterior & interior How to study building & site history when diagnosing the cause of peeling, flaking, or other paint failures Basic indications of failing paint on a building An encyclopedia of common painting mistakes that lead to early paint failure on buildings An encyclopedia of types of paint failures on buildings & a detailed dictionary of paint terms & paint failure terms Paint laboratory procedures for analyzing samples of failed paint from buildings

This article reviews common building exterior & interior painting mistakes, describes how to diagnose paint failures on buildings, and outlines a procedure for diagnostic field inspection & lab testing of failed painted surfaces. We include photographs of paint failures on buildings and more photos of forensic paint laboratory examination of samples of failed paint useful to assist in diagnosing the probable cause of each type of paint failure. Readers should also see Paint Failure Case Photographs-SITE and then Paint Failure Case Photographs-LAB and see PAINT & STAIN GUIDE, EXTERIOR for a guide to the selection and proper application of paints and stains on exterior wood surfaces. Our PAINT & STAIN LIFE CHART gives typical life expectancies of building exterior coatings on different types of wood surfaces.

The examples use building exterior paint failures (and remedies), but many interior paint failures are similar their origin and cure, including general information provided by some paint manufacturers, home improvement suppliers, and by National Forest Products Laboratory experts.

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 failure. 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.

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Experts representing paint manufacturers see many field failures of painted surfaces, often arising from a common cause. But getting a clear answer from these professionals can be tricky: the painting contractor is their customer, not the building owner.

Therefore, while most paint failures are due to poor surface preparation or painting in improper conditions of temperature or moisture, the "expert" may be reluctant to say so. Importantly, other paint failures are due to construction errors, building ventilation or vapor barrier errors, building leaks, or improper maintenance. It is important to understand why a paint failure occurred before re-painting a building. Otherwise the expense of a new paint job may be wasted. Our 1984 photo (left) shows the author (at rear) and Art Cady preparing surfaces for painting.

"Improper or inadequate surface preparation is by far the most common cause of house paint failures such as blistering, peeling and staining. If the new paint is separating from the old coat of paint, it is most likely due to chalking or some contaminant on the old paint that prevents the new paint from penetrating and binding to the old painted surface. If the peeling failure is down to the bare wood, it is most likely that the problem is a result of too much moisture within the wall, forcing itself out, taking the entire paint film with it."

"Over 65% of all paint failures can be attributed to poor or improper surface preparation. Two of the major causes of paint failure on exterior wood surfaces are either moisture passing through the substrate from the interior, or exterior sources of moisture getting behind the paint film. Temperature and humidity have major effects upon drying and ultimately upon the characteristics of the paint film. These effects will always determine the actual appearance and performance of the paint itself. Paint should be applied at temperatures of 70^o F, (21^o C), ideally, plus or minus 20^o F (12^o C) - unless product specifications state otherwise. A surface should not be painted if its temperature is within 5^o F of the dewpoint or the relative humidity is above 85%." -- PPG Exterior Failures.

The follow sections of this document form a checklist of building and site conditions leading to paint failures (such as peeling paint, blistering paint, chalking paint, cracking or alligatoring paint, or bleeding and stains through paint--terms defined below). The focus is on failures of painted wood surfaces on building exteriors but the paint failure diagnostic procedure can be generalized to other surfaces inside and out.

FAILURE CHECKLIST: EXTERIOR CLUES - Exterior Observations Related to Paint Failures

The photo below shows the author (on roof) working with Arthur Cady during a house painting project in New York. A photo of the finished paint-job is at SHORTCUT ERRORS.

• Dictionary of types of paint failures and problems, and other painting terms - see PAINT FAILURE DICTIONARY
• Pattern, location, and type(s) of paint failure found
• Paint failure pattern variations, such as by building location, exposure, weather exposure, surface type, wall field, trim, columns, paint failures on horizontal surfaces vs. frequency of paint failures on vertical surfaces, paint failure depth, type of peeling, alligatoring, checking or cracking,, or blistering or chalking
• Appearance of surfaces from which paint has separated: mill gloss, chalking, old paint, wood fibers, moisture push.
• Mapping of failed and not-failed paint on various building areas, overlaid on the above list of possible causes.
• Sun/shade/rain/wind/mechanical-damage exposure of the building surfaces
• Surface drainage control
• Roof runoff control
• Evidence of paint or caulk-created moisture traps such as paint-sealed lap joints at heavily-painted wood clapboards.
• Other site water/moisture sources, dominant direction of wind-blown rain and snow
• Paint chip information (wood fibers, prior paint layers, mold, or debris present or absent on back of paint chips) - examined in the field by simple magnification, and examined in the paint lab using high power microscopy and paint layer sectioning can provide rapid, inexpensive, and conclusive paint failure diagnostic aid.
• Thickness of coating materials, number of paint layers, and identification of the layer which appears to be separating. Collect painted sample materials or paint chips which will permit measurement of the dry film paint thickness (DFT) which can be compared with the required wet film thickness (WFT) by calculation using the percentage of volume solids in the paint.
• Paint thinners: what thinners were allowed, in what quantities, and what thinners may actually have been used? Compare the quantity of paint invoiced to the job with the coverage rating per gallon or liter of the paint. See paint thickness notes above.
• Evidence of water infiltration into building cavities, such as ice dam leaks into walls, leaks at windows, or general indoor moisture and humidity levels and history, such as a history of wet basements, crawl spaces, attics, or specific building areas or rooms.
• Information about insulation, ventilation, vapor retarders, water and air barriers used on and in the building exterior walls.
• Rust stains on buildings - see Rust Stains on Shingles
• Signs of exterior mold (misnamed "mildew:") on building surfaces on the exposed surfaces, between paint layers, between the building surface and the failing or other paint coatings.
• Samples of paint used at the building, including liquid samples of primer and top coat, for possible further testing.
• Paint cans which held the current and prior paint used on building surfaces: for recording of the manufacturer or "paint brand", lot number, tinting information, date of manufacture, and the producer's storage, application, thinning, area coverage rating, % volume solids, recommended application thickness, and other technical information.
• Paint and thinner MSDS sheets, if they are available; usually you can find these documents online from the manufacturer.

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AIR SEALING STRATEGIES
DEW POINT TABLE - CONDENSATION POINT GUIDE
MOISTURE CONTROL in BUILDINGS
MOISTURE PROBLEMS: CAUSE & CURE

PAINT & STAIN GUIDE, EXTERIOR
PAINT FALURE, DIAGNOSIS, CURE, PREVENTION
PAINT FAILURE CHECKLIST
  EXTERIOR CLUES
  INTERIOR CLUES
  SITE HISTORY
  PAINT FAILURE INDICATORS
COMMON PAINTING MISTAKES
  BAD SURFACE PREP
  PAINTING SHORTCUT ERRORS
  PAINT OVER MOISTURE
  INCOMPATIBLE PAINTS
  PAINT in SUN or WIND
  PAINT on STUCCCO, FAILURES
PAINT FAILURE DICTIONARY
PAINT FAILURE ANALYSIS LAB PHOTOS
Paint Failure Case Photographs-SITE
Paint Failure Case Photographs-LAB
PAINT LAB SAMPLE PREPARATION

PAINT REFERENCES

• 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]
• 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]
• Seeing Through Paintings, Physical Examination in Art Historical Studies, Andrea Kirsh, Rustin S. Levenson, Materials in Fine Arts, 2000 ISBN 99-051835 [ forensic science, technical reference, focused on art works - DF]
• Paint Handbook: testing, selection, application, troubleshooting, surface preparation, etc., Guy E. Weismantel, Ed., McGraw Hill Book Company, 1981 [Excellent but a bit obsolete paint theory and practice, also a bit light on field investigation methods, out of print, available used-DF]
• Art, Biology, and Conservation: Biodeterioration in Works of Art, RObert J. Koestler et als. Eds., Metropolitan Museum of Art, 2003, ISBN 1-58839-107-8
• Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF]
• Understanding Ventilation, John Bower, The Healthy House Institute, ISBN 0-9637156-5-8, 1995 [General building science-DF]
• Dampness in Buildings, Diagnosis, Treatment, Instruments, T.A. Oxley & E.G. Gobert, ISBN 0-408-01463-6, Butterworths, 1983-1987 [General building science-DF]
• "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]
• "Paint Failure Problems and Their Cure," Daniel L. Cassens and William C. Feist, National Forest Products Laboratory, online via Purdue University, http://www.ces.purdue.edu/extmedia/NCR/NCR-133.html
• "Why House Paint Fails," Mark Knaebe, US FPL, http://www.fpl.fs.fed.us/documnts/finlines/knaeb95a.pdf
• "Why Paint Jobs Fail," http://www.bennette.com/pdf/whyfail.pdf
• "Supplemental Guidelines for Removing Paint From Interior and Exterior Wood Surfaces," US General Services Administration, http://w3.gsa.gov/web/p/Hptp.nsf/0/40aff5a115b6a9e5852565c50054b4f4?OpenDocument
• "Common Paint Problems," http://www.parkerpaint.com/Common%20Paint%20Problems.html illustrates common paint failures - though their images and text appear to have been stolen from PPG - see http://www.ppg.com/getpaint/etraining/solver/exterior.html which catalogs paint failures and causes
• "Paint problem solver" from Lowes, http://www.lowes.com/lowes/lkn?action=howTo&p=Improve/PntPrbSlv.html&rn=RightNavFiles/no.html
• "Mill Glaze: Myth or Reality," R. Sam Williams, Mark Knaebe, US FPL, http://www.fpl.fs.fed.us/documnts/finlines/willi01a.pdf
• http://www.paintlab.com/failure.html is a lab offering paint chip failure analysis
• PPG Exterior Failures http://www.ppg.com/getpaint/etraining/solver/exterior.html

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More Information on Building Diagnostic Inspections and Repairs

• Exteriors, Landscaping, & Siding - Inspection, Repairs, Product Failures

• Quotes in the opening text of this document are from the encyclopedic but not quite complete paint website: PPG Exterior Failures http://www.ppg.com/getpaint/etraining/solver/exterior.html

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