Hurricane construction, house building methods in high wind prone areas.
This is a very brief page on a highly complex subject. I hope to add separate pages soon with a lot more details on the sections here.
Hurricane construction, what is it? It is an attempt by engineers,regulators and builders to build houses in certain areas to resist the effects of those devastating storms, called cyclone, typhoon, hurricane or even tornadoes.
We have all seen the TV images of natural disasters, hurricanes, floods landslides etc. It seems that there are more severe weather events happening, in these days of global warming.
What I am going to be talking about here is house construction in areas that are prone to severe wind storms. I live in Northern Australia and we call them Cyclones, in other parts of the world they may be called hurricanes, typhoons etc.
I am not an engineer, but a builder, so I will try to give you a non-technical over view of how we build houses where I live in Darwin. I have built houses the old way, before cyclone Tracy (Christmas Eve 1974, a date that none of us that went through it will ever forget), and ever since then under the new, far stricter building codes. So in effect, every job that I have done in the last thirty odd years, either full house, addition or alteration, has been built under strict cyclonic or hurricane construction building codes.
Imagine this, a giant hand digs into the ground around a house, and turns it upside down. Gripping the house by the foundations.
With the old methods of non-hurricane construction this house would just fall to pieces. The way that we used to build in the old days, (and the way that most of the world still does build,) was that houses were built just to hold themselves in place with a few nails and bolts, with the dead weight of the materials and gravity doing the work of holding them together.
It is a whole new ball game now. Engineers design the houses to withstand the huge forces generated by the wind. The house has to resist the direct side forces of the wind and the suction and uplift forces that are capable of defeating gravity and then some.
So, the whole house has to to be designed and constructed as a whole.
Back to the giant hand that is holding my house upside down. Imagine someone then placing a bag of cement everywhere possible on the inside of that roof surface. So that the whole of the roof surface has attached to it many many tonnes of weight that is working to break every connection that is holding the house together.
The whole house should still hang suspended from it's footings and not give way anywhere.
For a house to attempt to survive a severe cyclone or hurricane the structural engineer designs and the builder must build so that:-
So, from the soil to the foundation, to the wall,to the roof, to the last roof screw holding the roof sheeting, there should be a complete chain of connections.
Steel Frame Walls
Note! Timber frames can still be used, with hold down bolts and timber connectors, clad externally with structural ply to provide the bracing required. This however is rarely done, because of the cost of timber and labour of fixing all the connectors and bolts.
Roof structures vary from multi nail timber trusses to any of a range of all steel, or a combination of steel and timber layouts. The old all timber carpenter built roof has all but disappeared.
Deemed to Comply Manual - DTCM
Just to wind up this short article on a very complex subject, let me say that we have almost every material or component that goes into the structure of a house detailed in our DTCM. This is our so called Deemed to Comply Manual.
Not found it yet? Try this FAST SITE SEARCH or the whole web
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Please Note! The information on this site is offered as a guide only! When we are talking about areas where building regulations or safety regulations could exist,the information here could be wrong for your area. It could be out of date! Regulations breed faster than rabbits!
You must check your own local conditions.
Copyright © Bill Bradley 2007-2012. All rights reserved.