|When a chimney is leaking or
failing, usually the only solution is to re-do the
whole chimney, at least from the roof line up.
The main sources of chimney leaks are from the
flashing, the metal that covers the gap between the
chimney and the roof, and the cap, or the mortar
that covers the very top of the chimney.
These are the main causes of failure and the reason
for almost all our chimney jobs.
Two other sources of failure are a lack of a kick
out flashing, where a gutter butts to the chimney,
and the shoulder, or the angled part that connects
the narrow part at the top to the wide part at the
The loose and damaged stucco on the chimney is a result
of a leak and not a cause
of the leak.
We were working in Arlington, Virginia stuccoing a
chimney when a man stopped to ask me what was wrong
with his chimney. His brick chimney was leaking and
someone talked him into putting on one coat stucco
basecoat and a a synthetic finish for a solution.
After $ 2,000 his chimney was still leaking.
The solution someone had in the past was to
coat the bricks above the roof with thoro
Of course, this didn't stop the leak.
The thoro seal was peeling and popping
because the cap, or the mortar on top was
we corrected it is here:
This chimney was just stuccoed
6 years before we got here.
A kick out flashing, or a small piece
of sheet metal, would have prevented
A kick out flashing deflects water
from the chimney flashing into the gutter.
|You may have seen this chimney
The old flashing on this Spanish tile roof was
never put on tight to the substrate, in this
case, terra cotta blocks. The more the stucco
deteriorated, mainly due to deteriorating
mortar on the cap,
the more the chimney leaked.
The stucco is cut off to the block and
flashing is put on over the old flashing. What
we are doing is building a little roof.
When we stucco the chimney, mortar overlaps
the flange on our counter flashing.
Someone's solution in the past was to put a
big glob of goo around the base of the
chimney, which did nothing, but waste goo.
Just because a chimney looks
fine from the ground doesn't mean it is
I took this picture from my scaffold
of the next door neighbor's chimney,
when we were working in Northeast
I never showed him, because I
didn't want to make him feel bad.
This is a good candidate for stucco.
Probably the only reason it hasn't collapsed
is because the mortar
has washed out between the bricks
allowing water to escape.
I bought a drone with a camera for only 40
dollars and it is a great tool for inspecting
I explained that the mortar cap and the flashing
were the cause of his leak, and there was no need to
stucco over the brick. This is my competition for
you. Water runs downhill always. It doesn't travel
horizontally through brick.