I saw the damage done when Hurricanes Wilma and Katrina hit Texas and Louisiana. It was beyond belief.
I lived through the damage caused to Miami by Hurricane Andrew in 1991. I was in the devastated areas the day after the hurricane. The area, which encompassed most of the southern portion of Miami-Dade County, looked like hundreds of bombs had been dropped from B-52’s flying overhead. There were houses without most of their second floors, sometimes 3 walls were gone and only one wall on the second floor was left standing. There were gaps in the roof sheathing. The windows and/or exterior doors were blown out. Sometimes there was damage from flooding, if the house was near the ocean. Some areas were just a pile of rubble. The former houses were unrecognizable!
But we in Florida learned many lessons from Andrew. A new code was developed, the Florida Building Code.
However, the rest of the coastal South has not learned anything from Hurricane Andrew or even from Tropical Storm Sandy.
Many years ago I lived in Georgia and went to college there. I even had my first job in architecture in Macon, Georgia, where I had gone to high school. So I worked on buildings and houses which were built with wood framing, sometimes finished in wood siding, but more often finished with brick. This is often referred as “stick construction”. Most of the US builds its residential housing and some commercial buildings in stick construction. So what’s wrong with this type of construction?
Well, wood is just not strong enough, in my opinion, to sustain hurricane winds. There are those who argue that wood can be built to sustain hurricane winds. Maybe. But I wouldn’t want to be in a wood frame house during a hurricane. Wood needs to be perfectly attached to either another wood piece or to a steel strap, joist hanger, or some other type of steel connector. Who can guarantee that each and every connection is perfect? Wood to wood connections with just nails are prohibited in South Florida. No toe-nailing allowed without metal strapping. Where wood trusses are connected to a concrete tie-beam, the wood trusses must be attached with steel straps. In turn, the straps are embedded in the concrete beam.
So what should be the preferred construction for coastal states? What can Texas, Louisiana, Georgia, North and South Carolina, Mississippi, and Alabama, the southern states most prone to hurricanes, learn from Florida?
First, wood construction should be discarded in all of these states, especially those areas near the water. Wood construction should be replaced with concrete block and solid concrete construction. There is no reason FEMA (Federal Emergency Management Agency) should allow this type of construction. In case of flooding from hurricane activity, the wood walls would likely have to be replaced. Why should FEMA pay for that? In addition, wood attracts termites which concrete block does not.
Instead of wood houses should be built out of concrete block. Why does concrete block and concrete work better than wood? Concrete is poured and reinforced with steel. This makes the construction very solid. Since concrete is a liquid when poured, it fills the voids in the block and becomes one with the block. Concrete block construction contains reinforced and grouted cells at all corners, or as an alternate, there are concrete tie-columns.
In South Florida at the top of all walls surrounding the perimeter of the house, there is a concrete tie-beam. This tie-beam is also reinforced with steel, poured in place, and attached to the vertical steel coming out at the corners. Note that this vertical steel comes all the way from the foundation to the tie-beam, making the walls very solid and hard to move.
The Florida Building Code requires in concrete block construction that at each side of a window, at the window jambs, there be steel-reinforced and grouted cells to which the window is attached. In addition, these windows must be tested in an approved laboratory to prove that, when properly attached with the recommended attachments by the manufacturer, the windows will stay in place during hurricane conditions. In almost all high-end residential construction, the windows will be installed with impact-resistant glass. This glass is so hard that it is hard to crack even with a hammer.
Second, I would recommend that the ground floor and second floors be solid, reinforced concrete. The floor acts as a diaphragm and resists lateral loads on the walls keeping them from caving in during a storm.
And lastly, in addition to block walls and concrete floors, if it were my house, I would consider doing a concrete roof, either flat or sloped. Since it is difficult to pour a concrete slab in a sloped condition, I have also poured a flat concrete slab as a roof and then put the trusses with the finished tile as a decorative element on top. This is not normal Florida construction. This is above and beyond what is normal South Florida construction. However, this slab serves a purposes – it makes a hurricane shelter out of any room below because the concrete slab is so strong that even if the trusses blow away, the room and the flat slab will not!
Why do I recommend this double roof? I saw too many roofs during Hurricane Andrew become completely inhabitable because the roof had been destroyed or the gaps were so large that it rained inside the houses. Plywood sheathing is not a very good material to act as an underlayment to a tile or shingle roof. Although roofs have to have the roofing paper attached in a very precise manner as described in the code, and the sheathing also has to be attached to the trusses in a very precise manner, plywood, again being a wood material, is not that strong. Should the roofing tiles or shingles be blown away during a storm, the plywood is the weak link in the system. So if I were considering building a house, I would strongly consider this suggestion. In addition, as an added incentive in Florida, there is a potential credit from homeowner’s insurance policies for concrete slab roofs. This credit can be substantial. So I definitely would consider this type of roof.
It sounds radical, but this is building for permanence. When everyone else’s house is in tatters, yours could be a sound, habitable dwelling. So next time you build, think about using the Florida construction techniques described above.