How do I prevent condensation on boathouse roof?
New boathouse roof placed – galvanized. No insulation, roof screwed directly to 1″x4″ lengths that are tying the roof joists together. Previous roof was corrugated and galvanized and had no condensation, new roof is covered in condensation in the winter, seems OK in the warmer months. Location is Southern British Columbia, Canada. Boathouse is enclosed but is not airtight, plenty of ventilation.
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New galvanizing is much more reflective of solar spectrum and very low emissivity compared to old galvanizing. Paint it. The paint will of course fail over time, but it will change the heat gain/loss characteristics to something more similar to the previous roof.