Paint failing after insulation improvements
I live in a 1964 colonial in New England. I bought it a few years ago and it had a ventilated attic (with HVAC equipment…erg), single pane windows, minimal if any insulation in the walls. As part of a renovation we put closed cell foam in the attic (HVAC equipment is working much better now) and replaced about half the windows with new.
Last summer I had the entire house painted by a reputable painter. Already there is significant peeling and bubbling developing and water drips out from behind the siding when I press the bubbles. There is a clear moisture problem as seen here:
https://streamable.com/8qpq4t
I am aware that insulation improvements can create exactly these paint problems as a result of moisture issues. Example here: https://buildingscience.com/documents/insights/bsi-028-energy-flow-across-enclosures
I’m not sure I’ve really improved the insulation/tightness of the house enough to fit this example but it sure sounds like exactly what I’m experiencing.
I’m wondering if anyone has any advice here. I am considering putting small wedges under the siding in the problem areas to allow circulation there (as recommended in the Building Science article above). Any input would be appreciated.
Some old timers I spoke with recommended using siding wedges to open up 1/8″ or so gap under the siding in the problem areas (they are spread around the house on three sides). Has anyone tried this? Any other ideas?
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Replies
Boy that looks like bulk water rather than moisture
If the siding had oil based paint on it, it could result in similar issues. Quick check is to wipe it with acetone and paint thinner. If it comes off with acetone it is water based if with paint thinner oil. Also do this for any of the underneath layers.
Also, does the house have sheathing and housewrap under the siding? Some older houses don't and insulating them will cause paint issues.
The wedges might work and at this point, probably the simplest bandaid.
This reminds me of a FHB article going back to 2001: "Rain-Screen Walls: a Better Way to Install Siding" (https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.greenhomebuilding.com/pdf/RainScreen.pdf&ved=2ahUKEwiY6PDE8tKMAxXCGVkFHbfmFFA4FBAWegQIHxAB&usg=AOvVaw2a3DL0D6cUqwPl9Ksdf5o3)
Joe Lstiburek was involved in this as a consultant. The underlying cause in that case, where a house couldn't hold onto a coat of paint, was due to older housewrap being ruined by cedar siding being applied directly over the wrap. But the paint being ruined by moisture is similar. By adding insulation, there is less energy leaking out through the walls to help deal with moisture migrating outward to the cold sheathing and siding. While a bandaid approach may help a bit, I would think that a better long-term solution would be to remove the siding, make sure there is housewrap over whatever siding there is and that the windows are properly flashed, and reinstall siding over a rainscreen gap. More work, more cost.
We (insulation contractor) used to see this all the time after insulating - especially on the south side of the house ...
https://buildingscience.com/documents/building-science-insights-newsletters/bsi-123-capillarity-sucks
That makes sense. The strange thing is I never insulated the walls. Only the attic.
Would you usually put wedges in? Just in the areas of failing paint?