We are buy a new house and saw daylight through the roof around a vent in the garage. This is the explanation we got…
The vent stacks that are located over the water heater and the central
heating system that go to the roof are covered with what is called a bonnet.
The bonnet fits over the vent stack extending over and covering the
vent stack opening from rain, etc… The purpose of the bonnet is not only to
cover the vent stack opening but to have opening that allow the gas vapors
going up the vent stack to escape into the atmosphere. The light that is
visible are openings on the side of the bonnet that are used for the venting
of gas vapors. If the bonnets are completely sealed then the gas vapors
could not escape, and, that would be extreme deadly to the residents.
The bonnets are working exactly as they were made to function. The visible
light is normal.
Does this explanation make sense?