Markit wroteIt's aluminum and fecking horrible - should be banned.
Hi Markit,
It is actually galvalum (galvanized steel) - referred to in Indonesia for roof structure applications as "kuda-kuda baja ringan". It is not Aluminium. It is common and has been for many years. It is widely used in residential and commercial construction, not only in Indonesia. It is available in different gauges.
It's advantages over wood include:
- lighter (structurally advantageous particularly during seismic events)
- cheaper
- less propensity to warp and twist from exposure to humidity
- more consistent (vs the inconsistencies of lumber - ie. Type of wood, KD to X%, sapwood or not, etc)
- not susceptible to termites, etc
Disadvantages include:
- propensity to rust in coastal areas if not installed correctly
- thermal warping more significant than wood
- unlikely to be installed when an "exposed" rooftop (from the underside) is desired
Still, in Indonesia, luxury homes will generally use neither of the above two options as their primary roof structure (though it should be noted that luxury homes in Bali are more likely to use wood than in other parts of Indonesia because of the common architectural practice of exposing rooftop structures from the underside). Most luxury Indonesian homes will use a roof structure fabricated from I-beams, H-beams, C-channel and UNP steel. The structure is welded together, primed with and anti-rust coat (typically epoxy based), then covered with the chosen roof covering.
Its advantages include:
- high strength / weight ratio
- greater span capability (where needed)
- greater flexibility deviating from conventional truss arrangements (which can mean higher ceilings in some applications)
- very solid - minimal movement
It's disadvantages include:
- weight - it's still much heavier than galvalum (comparable to wood depending on the design)
- expensive - not only the structure of the roof itself is expensive, the heavier load means a greater dead load which pushes up the cost of the building's structure
- not as fast as galvalum to install
All the best,
Populaire..