Stove with Through the Wall Chimney Installation

Through the Wall Installation
In through the wall chimney installations, the chimney
enters the house through a vertical wall rather than the ceiling (see
through-the-wall illustration). This requires the use of an insulated
tee with cleanout plug, a wall support, wall closure or cover plate,
wall bands, roof flashing, storm collar and chimney cap. The illustration
also shows a wall radiation shield, firestop, roof radiation shield,
trim collar, and finishing collar. Cleanout access should be provided
beneath the tee cleanout plug.
It is important to follow manufacturer's instructions
regarding the minimum length of chimney that must extend into the living
area (as well as instructions regarding the maximum horizontal run of
chimney). Some chimney manufacturers offer adjustable length sections
to simplify determining horizontal chimney and connector lengths needed
from the tee to the stove. For other factory-built chimneys that do
not have adjustable lengths (and of course, cannot be cut) the distance
from the insulated tee (which the wall support positions in a fixed
place) to the chimney's minimum protrusion into the room must be made
up with a standard chimney length or combination of lengths that meet
or exceed the minimum length needed. The length needed will be the sum
of the space between the tee and the outside wall, the overall thickness
of the wall, and the minimum extension into the house.
An exterior chimney is subject to cold outdoor temperatures,
leading to greater heat loss and higher rates of creosote accumulation
and moisture condensation in the chimney. The best location for chimneys
for optimum performance and draft is on an interior wall of the house.
Cold hearth syndrome spillage is more likely with exterior, through
the wall chimneys, particularly in basement installations.
Bends like the 90 degree tee and any connector elbows
in a chimney restrict flue gas flow and affect draft. Through-the-wall
installations are also more expensive than entirely vertical installations.
A better performing alternative to through-the-wall may be an interior
chase (through upper floors for a basement installation.)
Consideration must be given not only to safety code height
for the chimney, but also to draft requirements. Additional height above
code minimums may be called for. In any event, roof bracing may be needed.