user wrote:
Most houses in my neighborhood have chimneys with three flues. Some have the
flue heights staggered, while some are all the same. Does the staggering
help prevent smoke exiting one flue from going down another? If so, how
different do the heights have to be to be effective? Does the order matter
(SML or SLM)?

Also, how much space does there have to be from the highest flue to a
chimney cap?

Thanks.



Are you sure the two of the flue liners aren't
just decoration? There is no reason to have
three operating flues unless you have several heat
sources.


The height of the flue above the chimney cap is
primarily a function of looks (and maybe how much
snow you get). Three or four inches is probably a
minimum. The actual height of the flue is based
on a minimum horizontal distance from the roof
line and height related to that point. It is
based on draw capability and blockage of air flow
by a near surface. Local codes may vary.