Zinc still the roofing material of choice as storm victims restore homes

There has been an increase in sales of zinc sheeting since the passage of Hurricane Melissa, as persons push to restore their homes, many of which lost roofs made from the same material during the storm.

Industry players say it is unlikely that zinc sheeting will be replaced as the material of choice for most roofs in Jamaica in the short term, because of their affordable cost.

At last check, zinc sheets were retailing for around $5,000 each at one hardware chain.

“There has been a huge spike, a big surge in demand for zinc, plywood and lumber,” Chris Bicknell, chairman and CEO of Tank-Weld Metals, told the Financial Gleaner, in response to a question about how the hurricane has affected business in the short term.

Tank-Weld Metals is a leading distributor of building materials in Jamaica, as supplier to hardware stores and contractors.

Bicknell said he expects the upturn in business to continue through to the end of the year.

At Category 5 strength, Hurricane Melissa exposed the vulnerability of zinc roofs, particularly in the western parishes which were hardest hit during the storm’s passage on October 28.

However, structural engineers also cited a general non-adherence to the Building Code as the true cause of the widespread devastation.

“In my opinion, we don’t have a Building Code issue; what we have is an implementation issue. So when I look at the pictures from Black River in the path of the hurricane, in the majority of them I saw, it seemed to me that we lost the roof sheeting, leaving the frames intact,” said David Goldson, a structural engineer with over 35 years experience.

Goldson said more attention must be paid to how zinc sheeting is applied to the frame of a structure, all of which is outlined in the Building Code.

“The roof sheeting needs to be connected to the roof framing, which needs to be connected to the walls, which needs to be connected to the foundation. Once you have a break in that path, then you’re going to have failure, he explained.

The engineer said further that the use of zinc nails to connect the zinc sheeting needs to be replaced by screws, as nails can only withstand a Category 2 hurricane, and would have little chance against a monster like Melissa.

He also suggested using more rafters in the framing, thereby reducing the spaces between each rafter; and for building practices to shift towards usage of hurricane straps, and away from the bending of steel rebars utilised in blockwork over the roof framing.

“I know it’s a cultural practice not just in Jamaica, but also in the Eastern Caribbean; but when the hurricane comes, it just straightens up the rebar and lifts off the roof. If people use the hurricane straps properly, their houses will stand a good chance of surviving a high-wind event,” Goldson said.

ABSENCE OF REGULATION

Howard Chin, a former president of the Jamaica Institution of Engineers, said Jamaica’s Building Code is unenforceable because of an absence of regulations. The Bureau of Standards Jamaica’s Building Code Committee, of which he is a member, drafted regulations more than a year ago, which the Ministry of Local Government has not yet approved, Chin said.

“The Jamaican Building Code is a mandatory Jamaican standard without the necessary regulatory teeth,” the engineer noted.

“The government is not treating this as the matter of national importance that it is; and with the damage from Melissa it has become even more necessary.”

Bicknell concurred that the use of zinc sheeting for roofing is not perfect, but can withstand high winds once properly installed.

“Even with winds of 200 miles an hour … there are steel roofs that did survive. But installing them properly is a must. If installed properly, it is a very cost-effective and time-efficient way of putting on a roof. But you can’t take shortcuts,” he said.

luke.douglas@gleanerjm.com