Customer contacted us after noticing a leak on ceiling below bay window. We recommended a water test to pin point the cause. (Learn more for our services charges on FAQs). We were fortunate to witness dripping from edge of copper roof, we were there early in a cold morning day. Condensation was happening between metal and roof deck of that bay window. However after water testing we found out, as I expected, leak was coming from window sill above bay window copper metal roof. However, we proposed to homeowner to remove metal roof of bay window and plywood so we could see cause of condensation. We ended up ceiling window sill to stop the major leak. As you can see it on pictures, copper roof was installed right on top of wood with no underlayment in between. Also air leakage from home caused the condensation. We ended up spray foaming area between drywall and bay window roof with 2 lbs spray foam, which is used as insulator and vapour barrier.

After replacing compromised plywood sheathing from water leaks and condensation, we reinstalled all copper panels. Proper new counter flashing was installed after cutting a reglet on mortar joints. Dymonic 100 caulking applied where metal met stone wall and mortar joints.