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Adhesion Malfunction: Formulating a Plan in Dealing with Peeling

A D+D Online Feature published December 27, 2010



More items for Maintenance + Renovation

by Jayson L. Helsel, P.E.

Homeowners in a vacation community on the East Coast were becoming increasingly unhappy with peeling paint on their upscale summer homes. The rustic, “weathered” look may have aesthetic appeal, but not in the form of wholesale paint cracking and peeling....
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Tagged categories: Coating failure; KTA-Tator; Restoration; Wood coatings

Comment from Cecil Given, (12/28/2010, 10:57 AM)

Consider 50% EB in any exterior acrylic or latex paint to help solve a peeling problem...add Penetrol to alkydsfor similar results...from former Flood VP


Comment from James Hobson, (12/28/2010, 11:04 AM)

Mr. Helsel: Major Paint Manufacturers frequently recommend use of an alkyd primer even if acrylic topcoat/s are used. In the light of this article, does this recommendation still hold true? Also have acrylic wood primers improved in penetration and durability to the point where they are equivalent or better than alkyd primers?


Comment from Mark Baum, (12/28/2010, 11:16 AM)

I have been is the coatings field for over 30 years. The best and only way to paint cedar siding is to not paint it. The proper way to take care of cedar is to stain it with a oil based product. Either a solid color or a semi transparent stain. Something with water replants would also help. Also if you go on to the cedar siding web site you will find that the proper way is to stain the back side before installing it on the house. I have done this to my house 10 years ago and still looks great. You just put a refresher coat on every 4 to 5 years as needed. Stain never peels.


Comment from ROBERT WILKIN, (12/28/2010, 11:46 AM)

I seems the many shingle applications are not painted for several montths. I thought the purpose of a good alhyd primer is to penetrate the wood and bind any minimal surface oxidation together and form a sound substrate for the paint. Could it be determined if a primer used?


Comment from Jay Helsel, (12/28/2010, 12:20 PM)

Alkyd primers (and finish) are certainly appropriate for cedar siding and wood in general. The coatings/system used should correspond with what the coating manufacturer recommends - and certain manufacturers may recommend alkyd versus acrylic coatings. The information I cited stating that acrylic coatings are the best choice is based on research published by the Forest Products Laboratory. This was not meant to negate alkyd coatings or stains. Cedar is often left uncoated or simply stained. Fewer problems would be expected with stains since these materials are designed to penetrate the wood and leave a minimal film on the surface. The drawback to stains is that they need reapplied more frequently since a stain versus a solid film coating provides much less protection to the substrate. When wood is left uncoated for some period the surface degrades and can cause delamination problems if coatings are applied. Cedar is more susceptible to degradation than other types of wood according to the Forest Products Laboratory. It is possible that a "penetrating" primer can improve or solve this problem, but if the total coating system film is too thick, delamination may still occur.


Comment from Mark Baum, (12/28/2010, 12:45 PM)

Robert, yes your theory is good for a flat wood surface that moisture can not get behind it but, you have to look at the application of the siding. This is a lap siding. Moisture is able to get behind the siding and every time the sun comes out after a hard windy rain and starts drawing the moisture out it that was blown under it, it weakens the bond from the vapor pressure and over time it peels.


Comment from Gary Baker, (12/28/2010, 6:14 PM)

While I almost always advise against alkyd topcoats on exterior wood, I can't help but wonder if the alkyd system in this case was recommended to eliminate the chance of tanin stains bleeding through... especially on the yellow houses.


Comment from Tommy Johnson, (12/28/2010, 7:32 PM)

I have been painting beach front homes on the east coast for over fifteen years now. We only use oil primer after the first coat of acrylic stain is applied. Hit the knots that are bleeding, and the nail heads, caulk, and then apply the final coat of acrylic stain. Oil is just to brittle once cured and won't flex like acrylic will. Its not uncommon for me to repaint homes 8-10 years after they are built and see the oil failing like this.


Comment from Lance C Futcher, (12/28/2010, 11:55 PM)

Does the same problem occur with pine weatherboards?


Comment from John J. Gallagher, (12/29/2010, 11:32 AM)

I did not read on how the oils were applied. Is this a case of too much product applied by spray and not back-brushed also adding to the premature peeling.


Comment from Joni McGinnis, (12/29/2010, 3:31 PM)

I agree with Mark. Semi or solid stain. Shingles allows too many areas for moisture to get in. I live on Maui and the UV would require frequent maintenance on the "sunny" side.


Comment from Jay Helsel, (12/30/2010, 9:51 AM)

A weathering study of wood prior to painting by the Forest Products Laboratory focused on cedar. However, the implication is that wood, in general, is susceptible to this problem. I would recommend going to the FPL website (http://www.fpl.fs.fed.us/index.php) and doing a search for "painting" which will show many references. Other questions: back priming and coating end-graing cuts are also recommended to prevent moisture from absorbing into the wood.


Comment from james croak, (1/5/2011, 8:30 AM)

have worked in coatings field for 26 yrs all in Massachusetts, best solution is semi transparent alkyd stain yes you need to redo after 5-6 yrs but no peeling. I have found all paints will peel off cedar shingles, alkyd paints are to hard and brittle and latex paints will not block stains and can also peel when the sun pulls moisture from the siding. In regards to coating all sides of the wood, not many jobs allow that to happen ie houses already sided, most builders dont have time to have you prime and paint the siding prior to application, Also pressure washing is not a good idea as it forces water into and under shingles.


Comment from Murray Schomburg, (1/6/2011, 2:58 PM)

Since these homes are existing structures, and we cannot see the condition of the interior vapor retarder, or even if one exists in good shape, or at all, it is possible that we are seeing some large quantities of cooking, or shower moisture originating from the interior, escaping to the exterior, that help ramp up the amount of moisture on the back side of the shingles as well. Comments above seem to all relate to moisture as a potential problem, but coming only from the exterior. We have to investigate and fix both sides at the same time as required.


Comment from Tom Schwerdt, (1/11/2011, 9:27 AM)

I would go so far as to offer the opinion that the choice of siding material was inherently sub-optimal when considering long-term durability and usual construction practice. Choosing a quality factory-primed cement-board product would offer fewer problems and more durability. As was pointed out by earlier comments, painting over weathered wood without removing the weathering (generally by sanding - quite labor intensive) is inherently a poor choice for durability. The weathered surface fibers of the wood are weak, and the paint largely is bonded to the surface fibers. Presto! We have peeling in short order. Factory primed cedar might be an option - but not one I have seen on the market.


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