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INSTrUCTIoNS For STrUCTUraL INTEGrITy aND FIXINGS
Structural support for solar heating
systems
Support
Installation on roofs must not produce restrictions
to rainwater flow that enables water to accumulate
or pond.
Solar collectors installed above metal roofs must
have clearance between the collector and metal
roof to avoid the accumulation of water or organic
matter. On corrugated metal roofing the clearance
between the collector and the top of the
corrugations must be no less than 25 mm.
In coastal zones, and in locations adjacent to
industrial areas clearance of 50 mm must be
provided to allow access from at least 50% of the
system's perimeter to wash the cladding under
solar collectors.
Figure 1: Panel bolt fixing
Figure 3: Panel stud fixing
All solar collectors must be fixed at no less than 4
points.
Solar collectors with an area of up to 4m
fixed with: 14 gauge screws in accordance with
Figure 2 into the centre of one of:
(a) 14 gauge screws in accordance with Figure
2 into:
(i) purlins 70 x 45 mm or larger, that span
no more than 900mm, or
(ii) purlins 90 x 45 mm or larger, that span no
more than 1 100mm, or
(iii) rafters, or
(iv) truss top chords
(b) 10mm galvanised bolts in accordance with
Figure 1 to purlins 90 x 45 mm or larger
that span no more than 1100mm
(c) 10mm galvanised bolts welded to 3mm
galvanised plate in accordance with
Figures 3 or 4 to either:
(i) rafters, or
(ii) truss top chords.
Where solar collectors with an area of greater than
2
4m
to be installed, each group of
28
Clearances must be provided to allow access to
and replacement of, all serviceable components.
The only point of contact between a solar heating
system and metal roof cladding should be where
penetrations are made.
The load of the solar system must be carried by
the building structure. The solar collector must be
fixed directly to the building structure and not to the
cladding. Means of mounting are shown in Figures
1, 2, 3 and 4.
COMMENT:
Care must be taken to avoid distortion of metal
cladding material.
The susceptibility for concrete and clay tiles to
break means that special care must be taken when
working on and attaching systems to these roofs.
Figure 2: Panel screw fixing
Figure 4: Panel stud fixing
panels with an area of up to 4m
from other groups by:
(a) At least one rafter or truss spacing along
2
, may be
the roof, and
(b) By at least one purlin space up the roof
slope
Where collectors are mounted together or
separately on a frame, the frames must meet the
requirements described in Paragraph 6.5.
Alteration of roof structure for
installation
Rafters, purlins and truss members may not be
cut, drilled, notched or otherwise reduced in
strength except for drilling for the attachment of
collectors or tanks.
Mounting of solar systems
Where solar collector panels are mounted above
roof cladding, they must be mounted so that the
weight of the panels is:
(a) transferred directly to underlying rafters or
trusses with connections conforming with
paragraphs 6.2.9 or 6.2.10, or
(b) transferred directly to underlying purlins
conforming to Paragraph 6.2.8, and
(c) carried by collector support battens
conforming to Paragraph 6.5.
All fixings that pierce metal sheeting must be
provided with adequate sealing washers or boots to
prevent leakage.
When used with steel roof cladding, fixings must
be zinc coated or galvanised.
COMMENT:
The fixing types and product must be in
accordance with the requirements for fixing used
on normal roofing installations.
Collector support battens
Collector support battens may either:
(a) run horizontally across the slope of the roof
as provided for in Paragraph 6.5.3 and
Figure 5, or
(b) run up the slope of the roof as provided for
in Paragraph 6.5.4 and Figure 6.
Where the collector is mounted on collector
support battens the battens must be constructed of
one of the following:
(a) galvanised mild steel with a minimum
section moment of inertia of 0.45 cm
(b) stainless steel with a minimum section
moment of inertia of 0.45 cm
(c) aluminium with a minimum section moment
of inertia of 1.3 cm
COMMENT:
A steel angle section 30 x 30 x 3 mm or an
aluminium channel section 25 x 25 mm with 3 mm
wall thickness meets the minimum stiffness
requirements of Paragraph 6.5.2.
Where the collector is laid on collector support
battens running up the slope of the roof those
collector support battens must be supported as
shown by Figure 6 by either:
1) each purlin crossed of a minimum
size of 90 x 45 mm on their flat
using the connection details given
by Figure 1, or
2) by a rafter or truss top chord at not
more than 1500 mm centres and
within 300 mm of each end using
the connection details given by
Figure 2 or by Figures 3 and 4,
and be in one piece
2
is to be separated
WARNING: THE INSTALLATION SHOULD NOT
COMPROMISE THE STRUCTURAL INTEGRITY OF
THE BUILDING ON WHICH IS INSTALLED .
Collector support battens running horizontally
across the roof slope, as shown in Figure 5, must
be in one piece and be at least long enough to
span each space between rafters or trusses that
have a collector panel above them. Battens may
cantilever up to 200 mm beyond a rafter or truss.
The collector support battens are to be fixed using
the details given in Figures 1, 2, 3 and 4 to either:
(a) each rafter or truss that they cross, or
(b) To purlins provided the purlins are a
minimum size of 90 x 45 mm on their flat
and span a maximum of 1100mm.
Figure 5: Collector support battens
across roof slope
4
, or
4
, or
4
.
Figure 6: Collector frame up slope of
roof
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