Home>Discussions>PAINTING & FINISHING>paint cracking and peeling on exterior wall
3 posts / 0 new
Last post
bill st
paint cracking and peeling on exterior wall

i am having a problem on an east wall on my house that i paintesd just last spring. i washed, let dry, then sc****d and sanded. i used a wagner paint eater which pretty much feathered the paint that would not come off. used an oil base primer and two coats of latex exterior paint. the paint that is cracking and peeling is coming off showing bare wood, primer with the paint. this wall, so far, is the only one that is doing this. i do seem to recall when i painted it was pretty sunny but not really that hot. anybody have any suggestion as to what i may have done wrong?? oh, the wall is cypress weatherboards.

Re: paint cracking and peeling on exterior wall


When peeling is down to bare wood, you can be quite sure that moisture is involved. The fact that you had to do so much prep work indicates that this wall has peeled before. It is not uncommon for eastern exposures to have worse peeling than the west or southern exposure, this is because there is rapid build up of vapor pressure when the warm morning sun suddenly heats up the eastern exposure from the cool of the night. The heat build up might actually be hotter on the western and southern exposure, but the rate of rise is not so rapid. The wood and paint are rapidly expanding and the bond is broken.

Obviously, you can't do too much to control the morning sun. You have to try to control the moisture source. How old is your house? How good is the insulation and interior vapor barrier? Does the sill plate sit directly on concrete or porous brick? Are you in a cold climate? Do you have adequate house exhaust ventilation to get rid of moisture generated by showers, cooking, laundry, even breathing? Is your humidifier set too high in winter? Was your siding back primed? All these factors can affect moisture in the walls and siding and subsequent paint failure.

I know of no paint that will hold up to excess moisture, although latex paints are much better at being able to let water vapor pass on through without causing the paint to peel. You might consider buying or renting a moisture meter and testing the siding. Moisture levels above 10 to 12% are very likely to cause peeling.

Possible aids to halt mositure:
- install bath and laundry exhaust vents
- turn down the humidfier if you have one
- prime the interior surfaces of exterior walls with a vapor
barrier primer
- improve vapor barrier in crawl space or dehumidify a deep
- seal gaps around plumbing or electrical which enter
exterior walls from the crawl space or basement ( a good
idea for air infiltration reasons in general)

bill st
Re: paint cracking and peeling on exterior wall

thank you so very much for your time and advise, i really do appreciate it and will look into what is causing the moisture.

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.