Getting to hurricane-proof homes

While a truly hurricane-resistant home may be wishful thinking, there are steps that can be taken in the construction phase to get a fighting chance when facing such a force of nature.
This is according to engineer Everon Zachariah, who was addressing participants at a public symposium on rebuilding after hurricanes Irma and Maria organised by the Antigua and Barbuda Investment Authority.
“The truth is that we can attempt to design and build structures that are able to resist hurricane loads, but we can never ever say that we are 100 percent hurricane-proof. So what we do is try to design a structure that has a certain high probability of being able to withstand winds of a certain order for a certain recurrent period.
Zachariah said there are four major areas that need to be addressed when looking to build a structure that is as hurricane-resistant as possible: the foundation, the structure, the roof, and openings.
First, the foundation.
“In designing the foundation, we have to ensure that that foundation is able to transmit the loads that are going to be imposed on the structure.”
According to Zachariah, not only is the bearing capacity of the soil important, but also the depth of the foundation, in order to provide proper anchorage in hurricane conditions.
“Quite often you find that contractors, in an effort to cut costs, they have foundations constructed sometimes out almost on the surface, one foot down, two feet down, three feet down. The recommendation is that you should try to have a soil investigation done that would determine what depth you should actually go to.”
According to the engineer, if a soil test could not be done, then it is recommended that the foundation be built at a depth of no less than four feet. He noted that this is only for single story buildings because higher structures would have greater requirements.
Zachariah added that knowledge of the area was also imperative, and he illustrated a situation in which a housing scheme was built in a flood-prone area with low floorings.
“We need to know how high we should carry that floor slab to avoid being flooded every time it rains.
Zachariah also recommended that reinforced concrete be used in foundations where possible. 
Turning to the body of the building, the engineer said this should be tied into the foundation and the manner in which this was done would depend on whether the structure was of timber or concrete.   
Zachariah also highlighted the old practice of using diagonal corner braces to shore up support of wooden structures.
“Apparently, during our rebuilding, we seemed to have forgotten a lot of that. What we have been doing is just omitting it. Those corner braces … serve to resist lateral movement that you would have during a hurricane,” he said, urging a return to the former practice.
He also called for the use of plywood instead of panel board in the construction of internal walls.
Regarding roofs, Zachariah noted that this is an area that usually suffers the most damage in storms because of improper construction or contractors again trying to cut costs.
“The roof should be properly anchored by using metal or steel straps over the rafters and passed into the concrete,” he stated. Roofs could also be anchored to both the external and
internal walls. “Currently most contractors fail to anchor them to the internal walls.”
And, on openings, the engineer said it was important to keep them as small as possible because the larger they are the more likely they are to be blown out or damaged during a hurricane.
Zachariah is a member of the Antigua and Barbuda Engineers Registration Board, which is responsible for the governance of engineering locally.