Modern appliances, whether oil, gas or wood-fired, are much more efficient and most of the heat they produce stays within the building. As a result, there is often insufficient heat in the flue and condensation and moisture will result. If there is not a water-tight liner in the flue, this moisture will bleed through the masonry as shown in the photos below.
Stains from wood stoves.
Stains from wood stoves.
Stains from wood stoves.
Stains from oil furnace.
Stains from oil furnace.
Stains from oil furnace.
Stains from gas furnace.
Stains from gas furnace.
Stains from gas furnace.
Moisture Stainingchim-admin2011-04-12T17:12:44+00:00