THE GREEN TRUTH LEGACY GREEN HOMES THE LEARNING CURVE SOILS FOR EARTH CONSTRUCTION ADOBEMACHINE.COM THE BEST BUY! FAQS
You Really Can Build a Tornado/Hurricane Proof Home
To view a video of tornado resistant construction click here!
For just a little more money? maybe so!
The topic of tornado proof and hurricane proof homes has come to the fore as a result of the intense hurricane season experienced last year by the Southern U.S. and the violent weather we have experienced last spring and are continuing to experience currently.
With so many homes in need of reconstruction due to these catastrophic events it has become a matter of urgency that information about this topic become available.
For many years the Earth Construction Industry has concentrated on seismic resistant construction in the Western U.S. resulting in acceptable building technology for most areas, however for many reasons the rest of the country has been resistant to or ignorant of this remarkable product.
Some of these reasons are:
Cheap lumber, Builders who know only stick frame construction, Uninformed home buyers, poor marketing, low quality machinery, High prices, insufficient systems, and more.
Even with the cost of concrete, lumber, steel and energy skyrocketing the naysayers as well as the stodgy lending and insuring bureaucracies have been resistant to alternative construction. This, however, is changing, with the demise of billions of dollars worth of real estate the insurance industry is rethinking their marriage to the lumber industry and that is of course followed by the lenders.
The need for LEGACY GREEN HOMES is paramount!
First
we need to address some of the issues and realities of some “modern”
construction methods.
As a contractor
I am familiar with many building techniques and the necessary methods used
to achieve them, so we’ll explore these.
Wood
frame, either 2 x 4 or 2 x 6, is by far the most prevalent building
material in the U.S. and the least costly as well as the least energy
efficient, least lived and least structurally resistant to wind damage.
Using standard building techniques the studs are nailed through the plates
strait into the ends of the studs then the bottom plate is bolted to the
foundation on 4’ centers. Plywood or oriented strand board (OSB) is then
nailed or stapled to the top and bottom plates and the studs. The cap
plate is nailed to the top plate with a slight angle with the trusses toe
nailed to the cap plate with hopefully a sheet metal angle bracket
(hurricane strap) nailed to the truss and the two top plates using a total
of 10 8d nails per truss end . Most codes don’t require solid plywood sheathing and
allow either cellulose fiber board or gypsum board for everything but
corners, I’ve seen many homes without any wood sheathing at all. Wood
trusses on 24” centers with 7/16 wafer board or 5/8 cdx plywood decking
is common. It is also common to use a brick veneer for the exterior finish
making the walls resistant to light projectiles but does not address the
roof attachment which is marginal at best.
Metal frame is an improvement over wood with the fastening using screws and or ramset hardened nails but most sheathing is gypsum board. The trusses are attached with metal brackets allowing for better wind lift resistance but the walls are easily penetrated and deformed by wind driven projectiles.
Panel construction:
A huge
improvement over stick frame as the interior as well as the exterior has
7/16 OSB sheathing with an injected foam core for insulation and strength,
The panels bolt together and down to the bottom plate and are tied
together with the top plate. Roof attachment with roof panels offers a
huge improvement to resisting wind lift if used otherwise the roof is the
same as with stick frame and is as subject to wind lift. The resistance to
projectiles is slightly higher and the walls are less likely to collapse
when hit by a large projectile.
Brick construction:
This is usually seen in older commercial and some expensive older homes, much stronger than frame construction but the outer layer detaches from the inner layer due to deterioration of the metal fasteners by corrosion as well as mortar degradation over time. This type of construction is much more resistant to wind lift with adequate roof attachment as well as penetration by projectiles other than cars and large trees. The energy use for the manufacture of brick is rather high (2 to 3 MJ/kg) though less than wood products amazingly (2.5 to 10 MJ/kg) see chart. There are a lot of pollution issues as well. See Environmental report.
Concrete construction, concrete masonry units (CMU):
In many parts of hurricane alley the CMU is the mainstay of hurricane resistant construction. With concrete cores and steel reinforcement CMU wall can take a real battering as well as offering a foundation attachment to the roof which is either concrete or metal. On the down side is horrible energy performance and sweating. While these homes are very strong they are generally built with a lot of windows and doors to make them comfortable so vulnerability to tornadic winds is also a problem.
Concrete construction, Insulated
concrete forms (ICF):
All of
the wood products can be improved by the use of foundation to roof tie
downs as well as wood wall sheathing, a brick or rock veneer at least 3”
thick and a roof membrane that ties to the walls rendering the roof wind
resistant to all but the most violent of tornados. As this will not
prevent damage from flying trees, cars, boats, and Mobil homes (tornado
bait) it will prevent damage from your neighbors house as it explodes.
Earth Construction, Berm or dug in:
Typically a concrete retaining wall of either ICF or solid reinforced concrete is built on 3 sides into the side of a hill or bermed with earth typically 10 or more feet thick. With a low pitched roof, usually earth, these homes are extremely energy efficient (see note) and with proper orientation and well designed can be very comfortable. usually the exposed side is frame or ICU with a large area of glass for light and solar exposure.
Note: The actual efficiency is compromised to a degree by the energy required to construct it using large quantities of both steel and concrete. (source) By my calculations the energy used for Concrete is roughly 1.026 MJ/kg vs .26 MJ/kg for Earth Block (my figures) The steel used for reinforcement adds to the disparity. (here is another source for embodied energy with numbers)
Earth Construction, Rammed Earth:
This home looks like any other but that is where the likeness ends. with 18" to 24" thick walls compacted with a mixture of soil and 6% portland cement you can sleep through any storm, I believe this construction could survive a mild storm surge given a proper foundation. Any roof system can be installed on this massive structure that will last for many generations. Extremely energy efficient but comes for a pretty price.
Earth Construction, Adobe:
Built from cast mud brick the adobe home is the most common structure on the planet. From the Middle East to South America adobe brick has been used to build every thing from castles to mausoleums. The city of Babylon and the city of Santa Fe were and are primarily adobe. Walls are from 8" to 48" thick depending on your need for thermal mass and or protection. The truth is you can never have too much dirt in your walls (unless they are frame) Like the rammed earth home these are wonderful legacy homes that will save you a ton of money in energy bills and like the rammed earth home it is quite labor intensive and expensive to have built but cheap to build your self. Not nearly as tough as the rammed earth house but actually more comfortable. I've lived in an adobe home since my childhood and prefer the feel of non cemented dirt.
Earth Construction, Compressed Earth Block (CEB):
CEB is the construction industries answer to the affordable legacy home. With massive walls 10" to 48" CEBs can be produced with very little energy. (less than .26 MJ/kg) yet create a thermally stable, tornado, hurricane, fire and bullet proof home that will last for hundreds of years if not more. As the precision block are simply stacked without the need for mortar (making them earthquake resistant) and without the need for skilled masons, The CEB system is fast and competitive allowing the median income home owner to obtain this Legacy Home
There are many other home building systems that are available with a simple search on the Internet. Most are not suitable for fast track builders.
If you are an owner/builder that would like more information about our owner/builder machines check out our PGM-150 and PGA-150 to see a cost effective way to build your own Legacy Green Home!
If you are a contractor who wants to enter the Compressed Earth Block industry armed with the best machinery as well as machinery designed for your aspirations come see us at www.adobemachine.com and use our site for your education then drop us an email or call us when you are ready to begin this remarkable endeavor.
Tornado damage note projectile in gable
Tornado damage brick building
Tornado damage stick frame with brick veneer
?
The real question is:
Can you as an individual and can we as humanity afford to continue building disposable homes?
Yes you can build a stick home that is wind resistant but not projectile resistant.
Yes you can build a concrete home that is both but why would you want to? Considering the energy costs both in embodied as well as ongoing you very well might not be able to afford the cost and the planet sure can't.
CMU home with concrete roof North Coast Dominican Republic
Bermed Construction
Adobe home Columbus N.M.
CEB wall under construction North Coast Dominican Republic
CEB home New Mexico, U.S.
