SA Affordable Housing January - February 2020 // ISSUE: 80 | страница 23

ADVERTORIAL
roofs) with shell insulation stabilises the indoor air warmth in
winter and provides coolness in summer.
Heat flows from a higher to a lower temperature level by
conduction, radiation and convection. Conduction occurs
through solid materials, radiation through the air and
convection through free air movement, such as air leakages
which can occur through gaps around exterior doors and
windows, airbricks, ceilings and other small holes in the
building shell.
Roofs are exposed to both high solar radiant heat gains in
summer and high heat losses during winter nights. The
roof-ceiling combination, therefore, warrants special attention
from a thermal point of view. Whether it is a tile or a metal
roof, install reflective foil over the rafters to act as insulation
and a waterproofing barrier.
Roofs and ceilings work in conjunction when it comes to
insulation. Thermal insulation is the material that slows down
heat transfer through the external surfaces of your home or
building. Thermal insulation is the invisible energy saver and
it could make your home or building considerably cooler in
summer and warmer in winter.
INSTALLATION
Pitched roofs with flat ceilings are the easiest to insulate.
Rather provide ceiling insulation during construction, as
retrofits are more difficult to install.
• Install insulation under the roofing material to reduce
radiant heat gain. Reflective foils are good radiant
barriers. Ensure an air space for maximum efficiency.
The best thermal design can be ruined if built badly. The
builder, and even the owner builder, should understand the
intention of the designer. The builder takes co-responsibility
for the final product since he is the last authority in the whole
process of building procurement who can discover and correct
mistakes made.
Adding or ‘retrofitting’ insulation to existing buildings
provides a major opportunity to increase comfort and reduce
energy costs and greenhouse gas emissions. For existing
buildings, the most common and easiest way to include
insulation is to retrofit insulation on top of the ceiling, the
most common application being a pitched roof with a flat
ceiling. Products suitable for this application are fibrous
blankets and/or cellulose fibre insulation.
Ceiling insulation is simple to fit if the roof space is
accessible. If a building has a flat roof or raked ceilings, there
will be no access into the space except by removing and
reinstalling the roofing or the ceiling lining. A thermal
insulative ceiling board could also be retrofitted to the
underside of exposed beams.
HOW TO SELECT THERMAL INSULATION
When selecting insulation, ensure that the material:
• is in compliance with the relevant South African National
www.saaffordablehousing.co.za
• Install insulation in the ceiling to reduce heat gain and
loss. In most cases ceiling insulation is installed between
the joists and trusses directly on the ceiling. Suitable bulk
insulation includes bulk batts, blankets and loose fill
insulation.
Thermal Insulation Products & Systems Association SA is a
non-profit company that consists of manufacturers, suppliers,
contractors and consultants in the South African Thermal
Insulation Industry.
Standard (product standard);
• is appropriate for the intended occupancy class in
accordance with SANS 10400 Part A;
• complies with the fire safety requirements given in SANS
10400 Part T and SANS 428; and
• complies with the recommended R-value for the relevant
climatic zones in accordance with SANS 10400 Part XA.
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