I'm wondering how those layers will stand up to the environment.. It seems a perfect weak spot for water to collect and try to get in if there are any imperfect

I'm wondering how those layers will stand up to the environment.. It seems a perfect weak spot for water to collect and try to get in if there are any imperfections and then when the hard frost comes, that water sits in a wedge and becomes ice and starts to push the layers apart, slowly creating hairline fractures for more water to wick into and freeze and expand ..