of a low pitched roof is critical, commonly referred to as a
flat roof, when it comes to the incidence of water precipitation
during frost conditions (absence of natural air movement)
This is the reason why smoke pots are employed in vineyards
an orchards around the world to create some movement however
slight to offset the damage to pants and fruit as may occur
when subjected to these conditions
air natural movement natural ventilation is not possible.
the occurrence of water precipitation to the underside of steel,
glass in a building, the surface(s) need to be isolated from
any air volume as may exist.
the point using a case study consisting of a building of approx
100 s/m, rectangular in shape, walls well insulated with R2.5
and internally lined in cement fibre sheeting, situated in the
The roof was of a steel cladding, pitched at 4 degrees, and
flashings extremely well sealed
lining, consisting of compressed wood and cement tiles was installed
approx 150mm under the roof and R3 Insulation was located above
the ceiling tiles.
A well insulated
area by any standard.....nevertheless.... toward the end of
every winter season the white ceiling tiles showed signs of
discoloration due to water presence.
what means were employed the only one that worked, was when
the roof was removed and foil was placed in direct contact with
the underside of the roofing material....a simple foil vapour
ventilation, and or with any situation, treating the symptom
is never as successful as stopping the problem.
is used or not the foil membrane against the steel roofing is
solutions will differ between Brisbane, Sydney, Melbourne and