Recently moved into a villa from the 70s. The metal chimney has at some point been covered with an additional lead sheet. The lead sheet seems to need replacement as it has a lot of holes. When I lifted it off, there was something resembling sand between the lead sheet and the chimney. Does anyone have any idea what it might be and if the sand serves a purpose?
I believe it is degraded mortar, not sand, that you see.
The mortar has functioned as a leveling on top of the chimney, but has probably been broken down by the acidic smoke from an oil boiler, or alternatively by acid rain.
The mortar has functioned as a leveling on top of the chimney, but has probably been broken down by the acidic smoke from an oil boiler, or alternatively by acid rain.
Thank you for your response,anaitis said:
Do I understand you correctly that mortar may have been applied on the galvanized sheet and then lead sheet?
The chimney is a 125 mm pipe with a cap of galvanized sheet, which is reinforced on top with a lead sheet.