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I have a problem with peeling paint on a 1920 house in Nashville, Tenn.

The house was gutted and remodeled 2 years ago. the wall construction is 2x4 studs, 5/8 drywall, no vapor barrier, 1/2 x 6 beveled spruce siding applied directly to the studs- no sheathing, no building paper, no housewrap. The stud cavities are filled with open cell foam applied directly to the siding. The paint job was poorly done with reports of the paint being applied without primer over siding that had been previously stained(age and condition unknown),and also reports of drywall mud being used to patch and skimcoat areas. The paint is lifting off the siding in bubbles the size of your hand. The failure is occuring on all areas of the house, both wet and dry, more so in the wet areas. The paint fails in the same way each time. First it turns loose in a 1 inch strip directly below the lap of the siding, the loose area then growing to cover the whole 5" face of the siding. I opened a 2 sf area of a bedroom wall directly behind an area that was begining to fail (including foam) and discovered that the 1' strip below the lap was very wet, the rest of the siding was only slightly wet if at all. The house was bought in late Sept. 09 and the paint job looked great. Following a 2 week occupancy at Thanksgiving the problems began and after a 2 week occupancy a Christmas the problems really accelerated. When the house was not occupied the heat was on with the thermostat set in the 50 to 60 range. My question- Is this only the result of a poor paint job or is the open cell foam applied to the siding part of the problem. Thanks, Tom

Asked by Anonymous
Posted Apr 30, 2010 2:51 PM ET
Edited Apr 30, 2010 3:45 PM ET


8 Answers

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Without an air space behind your siding, or even the normal triangular air spaces that usually occur when lap siding is installed over conventional sheathing, your siding has a hard time drying out. It gets wet two ways: from the rain, and also from the interior.

During the winter, moisture accumulates in your siding due to the continuous vapor drive from the warm, humid interior through the vapor-permeable foam to the cold siding.

This is a problematic installation. It doesn't surprise me that the paint is failing. The spray foam should never have been installed on the back side of your siding.

There is no easy, cheap fix. It may be easier to leave the existing siding in place and install rainscreen strapping over the existing siding, followed by new siding.

Answered by Martin Holladay
Posted Apr 30, 2010 3:51 PM ET



There is one potential easy and cheap fix (emphasis on "potential"), despite Martin's prognosis: Install wedge vents (www.wedgevent.com) between the clapboards to try to improve the drying. This strategy has worked for us on a number of houses with chronic clapboard paint failure. Don't know if it will work in a case this extreme, though (especially with the foam acting as an adhesive behind the claps). Maybe you could do it on one side and see how it goes.

Answered by Paul Eldrenkamp
Posted May 1, 2010 8:57 PM ET


Tom and Paul,
Paul's suggestion is worth trying, although I suspect that wedges will just split the clapboards, which are now all glued together by the foam.

Answered by Martin Holladay
Posted May 2, 2010 5:48 AM ET


Martin and Paul thanks for your info and advice. Are there any strategies that can be tried from the inside? Like vapor proof paint and a whole house dehumidifier. Also where do I turn to find an expert to check out the problem on site? If any one has experienced a similar problem I would like to hear about it. Thanks, Tom

Answered by tom kibby
Posted May 2, 2010 8:36 AM ET


Raw wood siding needs to be primed on all sides and edges, there are no shortcuts, oil primer is best but is not the most green. A latex top coat over oil primed wood will give many years of weather protection and the backpriming will foil vapor driven moisture and peeling paint.

Answered by Doug McEvers
Posted May 2, 2010 9:01 AM ET



It's possible the exterior condition is being exacerbated by interior humidity, but I think it's much more likely that the problem starts with exterior water wicking up between clapboards and wetting them from behind.

Maybe go to this site: http://www.bpi.org/tools_locator.aspx?associateTypeID=CTR to find a BPI-certified person in your area who could help diagnose the problem.


Answered by Paul Eldrenkamp
Posted May 4, 2010 2:49 PM ET


Thanks to all who are responding. here is some more info- the paint is also failing on the front wall which is covered along it's entire length by a porch roof extending 11' out from the house , being a continuation of the roof line of the house. So, exterior wetting, poor flashing, poor caulking, wicking are not in play at least on this wall. The first floor over the basement/crawl space has been sealed with a nominal 1' closed cell foam. The house did not have a range hood during the periods of occupancy at Thanksgiving and Christmas. Don't know if this helps or hurts, but please advise, this is a real head scratcher. Thanks, Tom

Answered by tom kibby
Posted May 6, 2010 9:15 AM ET


If the condition is the same on the side of the house that gets no rain exposure, there is a good chance that vapor drive from the interior is part of your problem. While it wouldn't cost much to paint the interior with vapor-retarder paint, I'm doubtful that you will be able to solve the problem that easily. The problem is, repainting the exterior is expensive, so you won't know if your interior paint makes a difference unless you make a significant investment in materials and time.

My advice is unchanged. Install vertical strapping over the existing siding, and then new siding.

Answered by Martin Holladay
Posted May 6, 2010 9:36 AM ET

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