Stucco meets wood - how to caulk

Old 05-23-16, 07:43 AM
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Stucco meets wood - how to caulk

1. Every year I scrape out and caulk the narrow gap where my stucco siding meets the wood trim of my window. And every year the caulking separates from the stucco and I need to redo my work. What can I do to make the seal last longer? I only have this problem with the one window pictured; because it is south-facing and gets a lot of heat in the summer, I expect that differential heat expansion is to blame. Thoughts?

2. Secondly, this window was installed in 2005 and is already showing some wear and tear. If I look to replace the window down the road, what type/brand would be recommended? Is wood trim the best choice for a south-facing window on a stucco house? It is important for me to maintain the heritage look of my house, but I'd prefer something that needed less maintenance.

We get 30 degree Celsius summers, and in winter the temperature drops to -10 or so...

Thank-you for your thoughts!
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Old 05-23-16, 10:14 AM
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What caulking are you using? some preform better than others. For latex caulk I prefer White Lightning but it could be necessary to step up to an elastomeric or polyurethane caulk. The window trim is securely nailed, right?
Old 05-23-16, 11:24 AM
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I agree with Mark that a polyurethane would be best. The size of the bead is also critical to its performance. Most exterior sealants recommend a minimum 3/8" bead. Any smaller and it will not have enough mass to hold together without cracking.

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