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?

post pics

The pictures came out too dark.

Depending on the type of vent that can be true. Pictures would help to give a definite answer.

“Does this explanation make sense?”


no,you shouldn`t be able to see light that enters the pipe opening if the roof flashing is sealed correctly,if you see light from the pipe seaming in the attic that would also be a problem—

Once again, Tar Monkey & I are on the same page.

I agree that there is acceptable light coming in.

Usually, what they are calling a “bonnet” is what we term a collar…

It’s all good IMO (& lacking a photo).

Yeah, I was thinking something like this pipe hat:

point is light entering the top of the pipe should not be seen(unless you are in the pipe)the bottom and collar flanges should be sealed also,if light can get in, so can water!—theses are common leak areas

if your looking down the way to the angle of the roof where the pipe/slate peice is your nine times out of ten going to see light . on and old slate roof where all the under slate felt has rotted u see light coming in everywhere just due to the fact your looking down towards the angle of the roof