To those who participated in a discussion about a peeling paint problem with my 1898 clapboard house beginning back on 21 August 2005, I think that I have found the answer in the June 2002 Fine Homebuilding. It is in an article entitled ‘Removing Exterior Paint’ by Jon Tobey on page 78. In a side-bar on page 82 entitled ‘Why good paints go bad’ are these statements: ‘A high-quality latex over oil can be a problem. The latex bonds with the oil underneath, and when the latex expands and contracts due to temperature differentials, it pulls the more brittle oil paint right off the surface. For this reason, it’s often best to remove all the oil paint from southern exposures on older houses before painting with latex.’ In my case, the oil paint is a century old, and the new paint is Sherwin Williams Duration paint, which seems to have a death-grip on the old oil paint.
This theory explains why the paint is peeling on the east and west sides on old-painted clapboard and not on new clapboard on the east side, why the north side old clapboard is only mildly peeling, why the old clapboard under the porches on the south side is not peeling, why new clapboard on the south side is not peeling, and why a wing wall (clapboard on both sides of a hollow stud-wall) serving as a privacy shield on the west sides of the porches on both the first and second floors is not peeling. Only old clapboard with insulation behind it that gets the full force of the sun, is peeling. The heat generated by the sun on the old clapboard wing wall is transmitted into the stud-wall air-space where it is dissipated and transmitted to the clapboard on the other side, thus not heating up sufficiently to expand and contract significantly.
I am presently having the old clapboard on the east and west sides stripped/shaved down to the wood. Whether this theory is correct or not, only time will tell.
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I believe you are very much right on the problem. If the paint is properly stripped, you will be very happy. Poor jobs with swirls and uneveness look like, well, crap.
Thank you for the info.I show houses and we look at the exterior and people ask me "why is that paint peeling"?I respond by saying "I don't know but I'm guessing it's because of moisture".Many Old homes have numerous coats of paint probably both oil and latexs and I think it gets to a point in time they can't be painted anymore. The paint just won't stick.^^^^^^
"The Older We Get, The Better We Were"
These factors are the basis for a high-quality primer for exterior applications... always. Over everything. Every time.
Troy Sprout
Square, Level & Plumb Renovations
We have the same problem, south side(weather side too) and latex over oil. A local paint company recommends a newer safe stripper over sanding/power cutting back down to the wood. I am going to try the chemicals and see what happens as ours is a big peeler at the moment.Those who can make you believe in absurdities can make you commit atrocities- Voltaire
What's a high-quality primer for external applications?
For brand new wood, I would use a good quality exterior latex primer. For old wood, that which is dried and weathered, I would use traditional slow drying exterior primer. The more porous it is, the more Penetrol I would add. I would feed the wood all the primer it will absorb, doing either a wet on wet 2 coat job or spraying it on as heavy as I could without having a drippy mess. This will penetrate through the questionable surface of damaged wood fibers and bind it all together with the solid, undamaged wood below. The primer will only absorb in until it dries. After it dries, future coats will only build up on the top and will never get a chance to penetrate further into the wood.
The primer depends on the application. I like oil base primer over old oil paints. I usually inform the Sherwin Williams counter guy of the application and get what is suggested.
I've had good performance from the SW PrepRite QuikSeal alkyd primer.
http://www.sherwin-williams.com/do_it_yourself/sherwin_williams_products/exterior_house_paint/primers.jsp
Gotta prime Fast because of major cure speed.Troy Sprout
Square, Level & Plumb Renovations
I am not familiar with your dilemma. I have always painted the siding on all sides and at evry joint before I installed it and have never had paint peel.
Are any of your jobs dating back to 1898? The house is 108 years old.
My parents owned a home dating back to 1882 until they sold it recently. It has been painted and has not had any problems. I have seen paint peel on the outside of homes which were only a few years old in the bathroom area. That does not happen if the siding is painted on all sides. I haved lived in areas where that is not a practice and they just plan on replacing their siding about every 25 years. They have never heard of painting the siding before installing it. They just look at me kind of funnny when I ask if they paint the siding on the back side. 22 years ago an owner asked me to install bare wood siding on one of his buildings because the siding was falling on the ground which was not over five years old. They installed the siding as bare wood siding but did not back prime it. I back primed the siding and it has never had any trouble. He sold the building in 2004 and the new owners decided to do some remodeling and you can tell where they put the new siding because in less than one year the siding is cupping because they did not prime it before they put it up.
Did you back prime the old siding before you insulated the house. If not this could be a big reason. No moisture barrier, and the craft paper insulation is not a good enough barrier. For some reason I am seeing more conrtactors working on older homes that back prime the new siding and do nothing with the old siding.
I did not back-prime the old siding before I had wet-blown cellulose installed. But, as I said in the original posting, the old siding on the north side is only mildly peeling and the old siding under the porches (facing south) is not peeling at all.
IMHO it is a matter of time before the other sides peel. I live in a city of old houses (Nations Oldest City) and if I walk out in front of my house I can see paint peeling on different sides of 5 houses. None of the contractors backprimed the old siding before insulating. It may be peeling in some places and not others due to the weather conditions when the siding was painted, but it is accelerated by the fact that the old siding was not back primed. A difficult problem to cure, if I could come up with a way to fix the problem easily, I could have five jobs tomorrow, and walk to work.
Back priming existing old siding sounds interesting. I'm working on a 100+ farmhouse that I have sripped the plaster and lath. There is no exterior sheathing - just clapboards. I plan on insulating w/unfaced batts. Do you thnk spray primer on the back would be a good preventative for possible future problems?
I have found that any exterior paint (mismixes from the box stores) will get the job done. I am in NE Fl and we have a mold and mildew problem so if I use an oil base I make sure that it does not contain linseed oil (this is the part of oil base that will enhance the problems). If you are going to buy paint I use Zinnzar 123, very good moisture barrier and will not promote mold and mildew.
I expect I'll get blasted for this, but I use the latex formulation of Kilz as a primer for everything, interior and exterior.
I came to that because it stays a little "sticky" even after it dries, and I used it for its intended purpose of stain blocking once, and I couldn't wash it off my hands or fingernails at the end of the day after it dried. Any other product (other than oil based) washes (actually kindof peels) right off. The Kilz II stuck like, well, glue, even to skin and fingernails.
Real scientific test, I know. ;-)
"Let's get crack-a-lackin" --- Adam Carolla
Kilz is a good product, I prefer Zinnzar brands, but that is why there are multiple products.. .one bad exp with one brand and you switch.