Extending a masonry chimney lined with a metal chimney liner
RIS may be used to extend a masonry chimney which has been lined with an approved chimney liner. This type
of repair is generally found where the original flue tile has been damaged by chimney fire or moisture and in cases
where the flue has been relined to reduce its cross section. The RIS anchor plate has a single wall connector sec-
tion designed to allow a metal chimney liner to be screwed directly to it.
Masonry Transitions
Masonry flue liners are typically rectangular, oval, or square, and they are rarely consistent in size. When
installing an RIS chimney to extend a clay tile liner the new round chimney must have a cross sectional area
equivalent to the original masonry flue. In some cases this requires a dramatic change in the shape of the flue
(e.g: a 6 X 12 flue adapted to 10" round).
When the original clay tile liner being extended is close to the same size and shape as the RIS chimney it is gen-
erally sufficient to construct a smooth, hand laid, refractory cement transition.
When the original clay tile liner is substantially different in size or shape from the RIS chimney it is recommended
to install a locally fabricated stainless steel transition section between the two systems in order to insure smooth
gas flow. It is not possible for ICC to offer transition sections as a stock item because of the variations in flue tile
size - even a "standard size" flue tile varies quite a bit from piece to piece. We recommend that this transition be
locally constructed using the following procedure (see the drawing on page 9).
• Make a paper template of the existing tile liner
• Have a local sheet metal fabricator make a rectangular to round tapered transition having the following properties:
• Constructed of .025 (22 gauge) or heavier type 304 or 316 stainless steel
• The rectangular section should correspond as closely as possible to the shape of the template and should have
a 1" flare at the end to allow it to seat squarely on top of the existing chimney -
see drawing
.
• The single wall connector on the RIS anchor plate should fit snugly inside the round section of the transition.
• For radical shape changes the tapered section should be 6-8 inches long - this will require a thicker bond beam.
The transition section should be wrapped with 1" of mineral fibre insulation prior to pouring the bond beam. This
allows for expansion and contraction and creates a
thermal break between the metal and masonry.
FIREPLACE APPLICATIONS
The anchor plate is designed to adapt an RIS chim-
ney to a masonry fireplace.
1. The anchor plate must be installed on a smooth,
structurally sound, flat surface.
2. Bolt the anchor plate to the top of the existing
masonry using 3/8" or larger metal anchors solidly
fastened into the existing masonry. Use the holes
in the anchor plate as a template to locate the
anchors.
3. Place a bed of refractory cement on the masonry
in the area the anchor plate will be in contact with.
4. Bolt the anchor plate down firmly. Allow the refrac-
tory cement to dry.
RIS Owner's Manual
ICC Chimney
10
