“HAVING a roof over our heads” is one of the most important sayings one will come across when building a home.
Interestingly, a roof isn’t just a structure over our heads: it’s also known as the “spine,” or the backbone of the structure – the one that protects or shields the home’s “vital organs.”
In the Philippines, homeowners are spoiled for for choices in roofing materials available locally, including pre-painted long-span metal roofing, corrugated GI (galvanized iron) sheets, clay or ceramic roof tiles, fiber cement shingles, asphalt and wood shingles. Some homeowners prefer laying out a the concrete roof deck.
The most commonly used roofing material by rank and type of application are the unpainted corrugated G.I. roofing for the low-end market, which we see in many communities around the country. But while G.I. roofs, popularly dubbed as “bubong na yero”, are the cheapest material available, they also corrode and deteriorate the fastest if not painted properly.
G.I roof sheets, however, are acknowledged by builders as economical and practical. And they don’t have to look boring: there are GI sheet roofs that are stamped and molded to look like clay roofs and are already available in terra cotta colors to resemble clay roofs.
Economical as they come
GI sheet roofs are the most economical in terms of cost per square meter, and the required support structure is also most economical. It is the easiest to patch up, as well, since these can be easily performed by a homeowner.
Under extreme situations where the the GI roof has been rusted through and through and looks like cheddar cheese, one can choose to hire a professional company to apply a material called ‘roof foam. This is sprayed on and leaves a 1.5-inch thick layer of waterproofed, insulated hard foam-in-place. This shield also has excellent acoustic properties that during heavy rains would not create too much noise (this is also called drumproofing).
Most builders swear by pre-painted longspan metal roofing as practical and economical, mainly because there are less joints which mean less chances of leaks.
Pre-painted long-span metal roofing is chosen by mid- to mid-upper class markets, and able to better resist corrosion. Some suppliers warrant their pre-painted products up to 15 years against corrosion.
These type of roofing also perform better against leaks, being cut according to the length required, thus avoiding horizontal overlapping, which is one of the causes of leaks. They are also installed using a special type of screw called the ‘tekscrew’ with rubber washer, which is reportedly water tight.
Roofing experts claim that long-span metal roofing trump commercial-length roofing sheets as these eliminate overlapping joints and minimize the potential for leaks. Long-span sheets cover more area, requiring less joints. Both ordinary and long span sheets are readily available in the market.
In the Philippines, most house-builders prefer pre-painted long-span metal roofing made of GI sheets. Other metals such as aluminum, tin, and copper can also be used to produce pre-painted long-span roofing sheets, albeit more expensively.
GI sheets are already factory-painted (and usually coated with zinc-aluminum to make it more durable and rust resistant).
Elegant but impractical
Clay or ceramic roof tiles and shingles cater to the high-end market. They look elegant but are very heavy and require metal under sheeting and battens to keep them in place. They seldom pose a leaking problem, but when they do, it would be a big task to resolve.
The concrete roof deck is one of the most difficult types of roof to maintain and to repair when leaking sets in. Even the most expensive type of waterproofing could fail at the slightest mistake during application. Sometimes, it takes redoing the whole deck area just to solve a small leak, because it is so difficult to find the source of the leak in the concrete.