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Gary D Brackins & Associates

Residential Designers for Custom Homes, Additions & Renovations Throughout Southeastern Massachusetts

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When the Winds Finally Came to Massachusetts

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Well high winds are still a blowin' in Massachusetts. In the 8th edition of the Massachusetts State Building Code designers must resist hurricane force winds just as in the 7th. Actually this is not complicated as long as you understand how wind affect buildings. Click on the house shown to the right to see how wind affects your home.

 

When I first came to Massachusetts from Florida and started my design business I had to become familiar with the state’s building code. The one item that stood out to me was no mention of wind loads. No where in the residential code did I find mention of uplift or shear forces. Being from Florida we had to deal with these forces for as long as I can remember. I spoke with some builders and local officials and was basically told, “we don’t have high winds here.” You can understand my amazement when I went through my first nor'easter!

 

Well not being born and raised in New England I had to do some research to find out about Massachusetts’ history with hurricanes. So I went to web and here’s what I found out (New England Hurricanes):

 

The last hurricane to strike was a category 2 hurricane named Bob in 1991. A category 2 hurricane has wind speeds between 96 and 110 mph. Before Bob was hurricane Gloria in 1985. Gloria had wind speeds between 75 and 95 mph making her a category 1 hurricane. Before Gloria was hurricane Belle in 1976, another category 1 hurricane. In 1961 a category 1 hurricane named Esther hit. The year before hurricane Donna, a category 2 hurricane struck. Edna, a category 1 hurricane came ashore in 1954, and two weeks before that a category 3 hurricane named Carol did a lot of damage. The Great Atlantic Hurricane that struck in September of 1944 caused severe wind damage all along the southeastern Massachusetts was a category 3 and the New England Hurricane of 1938 was a category 3. A category 3 hurricane has winds between 111 and 130 mph. I noticed from this data that we typically have a hurricane every 10 to 15 years, with the typical hurricane being a category 1 or 2. Hurricane Bob was 17 years ago so it looks like we are on borrowed time.

 

People here are the same way people used to be in Florida when it came to hurricanes, we don’t get them. Believe it or not that’s the way it was in Florida for a long time.

 

The first hurricane I remember was the same Donna (category 4) that hit here in 1960. Next was Betsy (category 3) in 1965. Our next hurricane was 14 years later named David (category 5) in 1979. We then went 13 years before we had Andrew (category 5) in 1992. Its easy to disregard hurricanes when they are spread out over such a long time. After the past few years people in Florida take the report of a hurricane seriously.

 

So its not “if” a hurricane will hit, its “when”. And if its been a long time since a hurricane has struck it seems to indicate the next one will cause serious damage. And it not need to be just a hurricane, all you need for damage is wind.

 

After the recent storm events we had in 2011 I hope people now realize the damage that Mother Nature can bring and reason for proper design and construction of what typically is their largest single financial investment, their home.



 

High Wind Provisions of the Building Code:

 

According to the 8th edition of the Building Code (which is based upon the 2009 International Residential Code with Massachusetts Amendments) we must design to resist 110 mph winds for our area along Buzzards Bay, which is upper limit of a category 2 hurricane. And according to my research that is the typical hurricane that strikes this region. For a listing of wind speeds in Massachusetts go here and find Table R301.2(4).

 

In the 8th edition (2009 IRC) Section R301.2.1.1 there are six design manuals/methods referenced by the Building Code for high wind designing in the 110 mph Basic Wind Speed Zones:

 

1.  American Forest and Paper Association (AF &PA) Wood Frame Construction Manual for One- and Two-Family Dwellings (WFCM); or

 

2.  International  Code  Council  (ICC)   Standard for Residential Construction  in  High  Wind Regions (ICC-600); or

 

3. Minimum Design Loads for Buildings and Other Structures (ASCE-7); or

 

4.  American Iron and  Steel Institute  (AISI), Standard for Cold-Formed Steel Framing-Prescriptive Method For One- and Two-Family Dwellings (AISI S230).

 



5. Concrete construction shall be designed in accordance with the provisions of this code.

 

6. Structural  insulated  panel  (SIP)  walls  shall  be designed in accordance with the provisions of this code.

 

Massachusetts amended section R301.2.1.1 to include the Guide to Wood Construction in High Wind Areas, and the use of the Massachusetts Checklist for Compliance (click this link to download the WORD document) to demonstrate compliance with the high wind provisions of the Building Code.

 

The Wood Frame Construction Manual 1995 edition was written after Hurricane Andrew. It was the first manual to actually address wood construction with regards to the physical forces homes must resist during a hurricane or high wind event. It is full of tables, charts and diagrams used to perform high wind calculations for the proper design of homes to resist high wind forces. AF&PA has released the 2012 edition of the Wood Frame Construction Manual.

 

After Hurricane Katrina the American Forest and Paper Association came out with the “Guide to Wood Construction in High Wind Areas for One- and Two-family Dwellings”. Basically they took all of the 110-mph wind information from the Manual and placed it in an easy to follow guide that can be used by builders and designers without the need for an engineer's understanding of the Manual.

 

The Board of Building Regulations and Standards adopted this Guide, and created the Massachusetts Checklist for Compliance as a prescriptive method of complying with the high wind provisions of the building code. According to the BBRS Official website (see question #3) a home designed according to the Guide and Compliance Checklist need not be certified by a registered engineer or architect for compliance with the high wind requirements. They may still need an engineer's certification if the foundation is within a Flood Hazard, Zone, steel beams are installed or other structural reasons. By meeting the Guide and Compliance Checklist many of metal connectors required by the Wood Frame Construction Manual may be eliminated.

 

With knowledge of the Guide and the Compliance Checklist a designer can make simple changes in their designs for compliance thus reducing the cost of construction. Its not that the metal connectors are expensive, it’s the labor involved in their installation that adds up.

 

What about all of these metal connectors?

 

Metal connectors have become more common place in residential construction following the adoption of the High Wind Codes. In fact there are prescriptive requirements for metal tie straps to connect an upper floor to a lower one, wall studs to sill plates and headers to studs. There are areas you can not get away from using them, i.e., attachment of the roof assembly to the walls. The Wood Frame Construction Manual also requires metal holdown connectors at building corners to attach the dwelling to the foundation.

 

The 8th edition One- and Two-Family Building Code is based upon the 2009 International Residential Code (IRC) with Massachusetts amendments. These are two separate books that you must use to determine building code requirements. Since the development of the 2006 IRC the code has allowed the use of wood sheathing and nails to resist the combined uplift and shear forces on wall. A Google search of "combined uplift and shear" will find many links. In fact the International Code Council, developers of the IRC Code also developed ICC 600 Standard for Residential Construction in High Wind Regions. Combined uplift and shear is shown in the Special Design Provisions for Wind and Seismic (ANSI/AF&PA SDPWS-2008) by the American Forest & Paper Association, developers of the Wood Frame Construction Manual. You can also check out APAWOOD.ORG for additional information.

 

Meeting the High Wind Codes can be accomplished with methods more in keeping with traditional construction techniques.

 

But I don't wanna change ......

 

People never like change. We like to whine when we have to do things differently, or learn something new. It's human nature to complain. We like to do today what we did yesterday. But if we do today what we did yesterday, how can we expect to have different results tomorrow than we did today? Make sense?

 

The Common Complaints

 

A lot of the complains I hear are based upon false information and assumptions. Lets talk about some of these.

 

I’ve had people tell me that all of these requirements are non-sense. They don’t apply to Massachusetts. It’s the insurance companies out to limit their liabilities, or window manufacturer’s wanting to make more money, or the metal connector companies just being greedy.


I’ve had people tell me that we have older homes that weren’t built by this code and they’ve survived all of the hurricanes. There are homes that are built on field stone foundations without any anchor bolts and they’ve never “blown away”. Whereas there is truth in these statements they can also be misleading. Here’s why:

 

Look at the actual construction of these older homes. They were built out of old growth forests, which means the wood was denser and heavier, interior rooms were smaller (meaning more interior walls providing shear resistance), exterior walls were balloon framed with continuous studs from foundation to roof, walls were covered with lath and plaster giving more weight and shear resistance to walls. Today we built out of light weight woods similar to balsa wood, everyone wants open floor plans with few interior walls, we build with platform construction (one floor stacked on top of another, think of a house of cards), we use drywall board instead of lath and plaster and we want our walls full of windows. We don’t use the same building techniques or materials that the older homes were built with. So its difficult to compare the two on equal terms. The homes today are lighter and weaker than the older homes. So the only way to build homes of today to be as strong as the older homes is through proper designing and proper materials, including metal connectors, or we go back in time and build homes exactly like the older ones. Wonder how many of us would want to do that?

 

I’ve had people tell me you have to use all of these metal connectors to build under today’s code. It's like building with an Erector set. This is not true. We do need some metal connectors, but plywood and nails if used properly can accomplish many of the connections we need in a structurally sound home. Again it’s knowledge in materials and their proper usage.

 

I’ve had people tell me we have to use hurricane glass in our windows. Again this is not true. The building code states that if within one-mile of the mean high water line of the ocean, and if within a 110-mph wind zone exterior wall openings must be protected. This is called the Wind Borne Debris Zone. We can accomplish this by one of three methods as required by the Section R301.2.1.2:

 

1.    hurricane resistant glass

2.    plywood panels

3.    approved shuttering systems

 

Of course you may want to use hurricane resistant glass for the second floor windows instead of being up on a ladder with a large sail (plywood panel) in high winds (of course we always wait to the last minute in case the storm misses us).

 

The people that complain about the insurance companies causing all of this must remember one point, “they don’t write insurance within the coastal areas anymore” so they aren't limiting their liabilities with the new code. Window manufacturer’s would rather produce a “cheaper” window not a more expressive one, because cheaper sells more. And the metal connector companies have always made metal connectors that were used in other parts of the country.


So its not the insurance companies fault, nor the window manufacturers, nor the metal connector makers. Its because of the way we build and the materials that we use. Its because of structural failure of homes in other parts of the country during storm events. Its from wanting to protect people and their families during a storm, not having a home collapse on them that have led to these changes. As Bob Dylan once said, “the times they are a changin’.”

 

I must admit it seems there is a lot of confusion out there on the high wind requirements. This is why designers must detail the proper construction methods needed to comply with these building codes. It’s why builders must follow the designers’ drawings. Recently I had a project that the construction of the required shear walls were properly detailed for the builder, every nail size called for and where they needed to go. How to block the panel and the size of plywood to use. However he failed to follow the detail and did his framing the same way he had always framed. Needless to say this project “failed” inspection by the local building official and the builder was required to “tear apart” his work and redo it to comply with the code. Unfortunately education costs money, whether in college or the school of hard knocks.


People never like change.

 

Trust me, I didn’t like having to change the way I design homes. But we can learn and adapt to the change, or we can get left behind. Massachusetts is the last coastal state to adopt the high wind codes. Most of our neighbors have been doing this the past four or five years. Like all new things there is a learning curve. In a few years we’ll look back on this an laugh at the challenges we’re going through now. Notice I said "in a few years."

 

Windborne Debris Zones & High Wind Codes, Which is Which?

 

There seems to be some confusion on the difference in the high wind codes and the Windborne Debris Zone. I've had builders tell me their project doesn't have to meet the high wind codes because it's three miles from the ocean. Some think that the high wind codes only apply if you are located within this "windborne debris zone (see definition below)". Section R301.1 Design states "Buildings and structures, and all parts thereof, shall be constructed to safely support all loads, dead loads, live loads, roof loads, flood loads, snow loads and wind loads as prescribed by 780 CMR Massachusetts State Building Code for One- and Two-Family Dwellings. The construction of buildings and structures shall result in a system that provides a complete load path capable of transferring all loads from their point of origin through the load-resisting elements to the foundation." The high wind codes applies in the entire Commonwealth of Massachusetts, with certain areas having a different basic wind speed than others. Table R301.2(4) provides the basic wind speeds for Towns and Cities in the State. If you're in a 110 mph baisc wind speed zone then your building must be designed according to specific design manuals per Section R301.2.1.1.

 

The 8th edition of 780 CMR Massachusetts State Building Code for One- and Two-Family Dwellings defines a Windborne Debris Zone (click on link to view map) as areas within hurricane-prone regions within one mile of the coastal mean high water line where the basic wind speed is 110 miles per hour. The coastal mean high water line, in Massachusetts 110 mph wind zones, forms the outer edge of the red bands overlaid onto the satellite images found on the MA Department of Public Safety website at www.mass.gov/dps.

 

So all buildings must be designed to resist imposed wind loads, and those within one-mile of the coastal mean high water line with 110 mph basic wind speed must also protect openings in exterior walls. Confused yet? Welcome to my world .....