Page 18
INSTALLER GUIDE
7.4 Lintel installation.
1.
The lintel should be either steel (Catnic) or
reinforced precast concrete. It should be 750mm
long x 75mm deep x inner leaf thickness.
2.
The opening should be, as near as possible,
centrally below a joint in the inner leaf block.
3.
Cut out the opening for the lintel.
Where cutting through masonry, drill pilot holes
and then cut out the slot using a mechanical cutter.
This will minimise damage to the surrounding
structure.
4.
Insert the lintel. Bed the lintel on mortar.
Don’t dry bed.
Slate pin to ensure the lintel and
structure above is secure and safe
5.
Make the opening below the lintel by
removing the masonry and clearing debris. If
the cavity has loose fill (e.g. granular)
insulation material, pack the edges of the
opening with Rockwool as you proceed to hold
back the insulating material.
6.
The wall cavity must not be bridged other
than by the flue tube assembly. The fire box
must not project into the cavity
between the inner and outer walls by
more than 10mm.
See wall preparation for flue
tube.
The cavity should be sealed where the
opening has been cut. We recommend
filling fully across the cavity with
Rockwool or equivalent to at least
100mm all around the flue tube. Fill at
the bottom of the opening to the level
of the hearth/fireplace floor. It may be
simplest to back fill the cavity with
the insulation material and then cut
through the insulation to the size of
the flue box hole.
Figure 12. Flue pipe insulation
Figure 11.
Figure 10.
