Hurricanes are scary. I wouldn’t wish the experience on anyone. So we are going to discuss some designing tips for building a new hurricane proof house. Why? Well, have a look at this video produced by a news team below.
Step 1: Ground floor/ground sill should be raised
Hurricanes bring plenty of torrential rain. Your home should be raised off the ground to make it a hurricane proof house. 3ft (900mm) would be ideal but as this is a bit high for some people, 24″ is often used. The ground floor/ ground sill should therefore be between 18″(460mm) – 24″ (600mm) off site ground level and up to 3ft from the ground if possible.
With hurricanes, the fury of the wind can uproot buildings easily so ensure your ground sill is tied to the foundation walls which are tied to rock. If there is no rock , use concrete piles (concrete columns drilled into the earth) to secure the slab to the earth. If there is no ability to use costly piles, tamp down marl and compact it so it becomes LIKE rock on which to build the foundations.
All foundations and slabs should be reinforced with steel.
Step 2 – A Hurricane Proof House is strapped!
A hurricane proof house must be tied down or strapped down right up to the roof. Hurricanes are not only about fierce winds. They are also about the floods and the flying debris. So in order to withstand extreme winds, floods and debris, the house needs to be strapped and reinforced at every junction.
Below we see how homes are damaged during hurricanes ( compliments of the Weather Channel.) Most of the damage is caused by the lack of strapped rafters and walls not being reinforced.
In Florida and North Carolina, they use huge wind farm testing areas to see how homes hold up during hurricanes. It was discovered that hurricane straps holding the roof to the structure and the straps holding the studs to other structure (such as floor structure) are key to withstanding high winds.
The FLASH (Federal Alliance For Safe Homes) group published a video on how to build a stronger home with straps.
Step 3: Hurricane Proof Houses Have Impact Resistant Windows
Today, homeowners of new hurricane proof homes can enjoy large areas of glazing with impact resist windows instead of small windows of the past. These windows have impact resistant glass and beefed up reinforced window frames.
They are also screwed into the wall every 2 ft with no less that 50mm long or 2″ screws to ensure the windows resist the suction from the speed of the hurricane winds.. In other words they are extra strong. The Homebuilding/Remodelguide explains hurricane resistant windows clearly should you wish more detailed information. These are the best ways to stop windows from “popping out” in bad weather.
Impact resistant windows are only as good as the quality of the reinforced frames. To see a range of various styles of storm ready windows , check them out at Lowe’s or HomeDepot.
Most impact resistant windows are double glazed making them more expensive. Often they also use laminated glass as well for added strength and protection. All of this naturally increases the price of each window!
S0, if you can’t afford the impact resistant windows, try adding an anti-shatter film on your windows at least. The acrylic film, which is applied with soapy water, will add strength to your single glazed windows. The film will not only deter burglars, it will deter flying debris! I also love that many of the films protect against UV rays as well! Either way, they will assist with strengthening your home against extreme weather. The fact that the glass won’t fall apart alone may stop the uplift on your roof! Here are 3 brands to check out:-
Step 4: A Hurricane Proof Home Roof
I tried to find a photo of an undamaged roof AFTER a hurricane. But maybe this old newscast above from 2017 shows it all. Roof damage from hurricanes ia very common and almost the norm as roofs are the first line of defense during a hurricane! Too many times corners are cut when it comes to constructing a strong roof. So let’s not have your home added to the list! There are a few key components to a storm proof roof so we listed them below.
1. The strongest roof in a hurricane is a hip roof. The surface area is less for the hurricane to use or suck upwards.
However, gable and shed roofs are very strong also once they are correctly tied down with hurricane straps. (see Step 2)
2. The optimum angle is 30 degrees. It reduces the chance of the roof becoming a sail during the storm.
3. Using galvinized sheets is one of the strongest materials to cover the roof and can take up to 160 mile an hour winds if installed correctly with the right screws. Asphalt shingles (as seen in the picture above) will withstand strong winds if installed correctly.(Hint – it is down to the shingle overlap and amount of nails per tile.)
4. Roofs are stronger if fully sheathed or covered with plywood onto rafters under the roof finish. There is lot of debate about this as costs are higher and it exposes the home to more moisture and termite problems. To solve the latter , the roof often needs roofing paper/felt and the property needs a maintained termite spray schedule.
It was interesting to note that, in 2017 when Irma devastated the Caribbean, the homes with a ply sheathing withstood the hurricane longer and protected the occupants better.
5. Overhangs must be minimized as the hurricane winds can lift a roof off by uplighting or pushing up the overhang areas to pull rafters out of the wall.Therefore we use no more than 12″ and ensure the strap is over the rafter.
6. If you do wish a large overhang, (for instance …in a patio), attach the overhang roof structure separately to the outside wall on a bolted wood base (sleeper) so that high winds can take away the balcony or verandah roof and leave the main dwelling intact. You may also choose to hold down an open space such as a verandah using columns from the ground to the roof .
Step 5. Designate or design in a storm bunker
If possible , design in or designate an interior room as a storm room which can be a reinforced wall bunker in the most interior part of the house. In the same way tornado region homes have basements for weathering tornados, a concrete walled room in the centre of the home is good to weather the storm and is an ideal addition to the home. Kit it out with water and basic provisions and even your most valuable documents. In our home we have a small office which does the trick.
To Close Off…
Let’s recap then…
- raised groundsill
- tie down the building with reinforcement and straps
- Use impact resistant windows and or anti-shatter film at least
- make sure the roof is well sheathed,strapped and angled correctly
- designate or design an internal bunker.
…and you are on your way! With these 5 options highlighted, you will have a much stronger home.
If you have lived through a hurricane, please drop us a line and let us know of your experiences. Did any of the these 5 tips work for you? (We value privacy and nver pass on your information!)