INSTALLATION METHOD 3 (timber framed buildings)
Where removal of any part of a timber frame is undertaken the structural integrity of the wall must be
retained. The advice of your local building control officer should be sought. If the property is under any
NHBC warranty it is also advised that their advice on this kind of modification is sought.
Either of the two preceding installation methods may be adapted for timber framed buildings, providing
extra care is taken in ensuring combustible materials are adequately protected from the effects of heat.
The appliance must be installed in accordance with the British Gas documents DM2 and DM3 or the Institute
of Gas Engineers published procedure document IGE/UP/7.
Special attention must be paid to the location of studwork frames of the inner leaf and the appliance posi-
tioned accordingly. Wires and pipes that run within the wall must also be taken into account.
Installation as per
method 1 (against
inner wall)
When using this
method of installa-
tion the following
amendments should
be incorporated. A
75mm air gap or
75mm of insulation
(e.g. rockwool) must
be provided between
combustible materi-
als and the sides and
rear of the cavity
box. A 100 mm air
gap or 100mm of
insulation (e.g. rock-
wool) must be pro-
vided to the top of the cavity box. It is also a good idea to enable as much airflow as possible, into and out
of the area behind the fire without excessive heat loss from the room when the fire is off.
Installation as per method 2 (recessing into a wall)
When setting the
appliance into the
wall find a suitable
position between
frame timbers and
open up the hole.
Secure back the
damp proof mem-
brane to prevent
ingress of damp.
Again 50mm insula-
tion plus a 12mm
thick fire retardant
board, 'Superlux' or
equivalent, must be
provided between
combustible materi-
als and the sides and rear of the cavity box. 100 mm of insulation plus a 12 mm thick fire retardant board,
'Superlux' or equivalent, must be provided to the top of the cavity box. The exposed cavity should be sealed
off using non-combustible board, ('Supalux' or equivalent), made into a 4-sided box. It is also good prac-
tice to further insulate the cavity with a 50mm layer of Rockwool outside the Superlux box. Note that the
appliance should not be allowed to bridge the cavity in this installation method. It is also a good idea to
enable as much airflow as possible, into and out of the area behind the fire without causing excessive heat
loss from the room when the fire is off.
6.5
8
Figure 7
Outer leaf of building
Non combustible back panel
Combustible inside
wall of building
Rockwool insulation 75mm sides and
rear, 100mm top
False chimney breast
50mm of Rockwool to insulate cavity
Superlux Box, 12mm thick, External dims;
Height 677, Width 529mm, Depth 167mm.
Rockwool insulation, 50mm sides
and rear, 100mm top.
Combustible inside wall
of building
Figure 8
©
2009 Focal Point Fires plc.
