2.3
PREPARATION OF THE COMBUSTION CHAMBER OPENING
(INTO EXISTING CHIMNEY BREAST)
An opening should be constructed to the following dimensions in the existing
chimney breast.
Fig. 6
The opening needs to be sufficient to accomodate the combustion chamber. To
support the wall above the opening, a suitable lintel must be inserted across the
top of the opening. The lintel could be either pre-cast concrete or steel - Catnic
CN52 or CN 46 could be used, depending upon the inner wall thickness. Before
proceeding with the installation of the fire, an assessment of the area immediately
above the fire is required, see Fig. 7 overpage. If there is no existing openings
within either triangle, proceed with forming the opening. However, if opening or
beams occur within either triangle, then you should seek specialist advice from a
structural engineer or consider relocating the proposed position of the firebox.
NOTE : Please ensure that suitable cut outs in the sides and front face of the
chimney breast are implemented for fixing of the flue pipe, and for future
servicing.
9
Minimum Width 635mm
Maximum Width 645mm
Minimum Height 465mm
Minimum Depth 316mm
Lintle must
project 150mm
either side of the
opening if
cutting into an
existing chimney
breast
