Indoor Air Quality

According to Wikipedia, Indoor Air Quality is defined as such: Indoor air quality (IAQ) is a term referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.

IAQ can be affected by microbial contaminants (mold, bacteria), gases (including carbon monoxide, radon, volatile organic compounds), particulates, or any mass or energy stressor that can induce adverse health conditions. Indoor air is becoming an increasingly more concerning health hazard than outdoor air. Using ventilation to dilute contaminants, filtration, and source control are the primary methods for improving indoor air quality in most buildings.

As builders, what can we do to improve air quality, and what can we do to eliminate the causes of indoor air pollution? We've been told for a few years now that we are building homes tighter and tighter, and to some degree that is true. What we have to realize is that as we tighten up the building envelope, we are creating other areas where the envelope can be penetrated if not treated properly. The beginning of a good building envelope starts with the sheathing and the water and vapor barrier. We have recently begun using the Zip Wall System by Huber Engineered Woods, but have successfully used OSB sheathing with a Tyvek Wrap barrier. The key to either system is to make sure your framing crew, or whoever is installing the wrap and tape system, has the appropriate tools, a knowledge of the proper installation of the system, and adequate supervision to guarantee all joints are taped per manufacturer's recommendation. Depending on which system you use, there are also differing opinions on the best details for sealing the windows and the doors. Once again, you need to make sure you know what the manufacturer's recommendations are in this area, and I believe, you need to take a little more time and spend just a little more money to insure that you have these areas sealed beyond those minimum requirements.

The second areas to address are the penetrations through the building envelope. The average home can have anywhere from 20-40 penetrations through the building envelope, depending on how many exterior lights, outlets, hose bibs, condensing units, etc. We are using a product called Quickflash Weatherproofing Products to help to seal these areas prior to installing siding, plaster, or masonry on the exterior of our homes. Quickflash has multiple flashing sizes to accommodate almost every size of penetration for electrical, plumbing, gas, and HVAC systems. When installed properly with your vapor and water barrier, these flashings provide a no caulk friction seal at all penetrations, and give the builder an extra layer of protection against water and air leaks.

Insulation is the next layer of protection we install to seal the envelope. We use a hybrid insulation method, which effectively and efficiently provides excellent energy performance with a lower cost to install compared to an all foam application. The hybrid system involves the use of spray foam at the underside of the roof deck and in all high risk or problem insulation areas like kneewalls, rim joists, cantilevers, overhangs, etc. The walls are then sprayed with cellulose insulation, which is a full cavity application that not only provides an excellent seal for your energy envelope, but consists of 80% recycled materials. Closed cell spray foam has an R value of approximately 6/inch, and the cellulose produces an R value of 3.7/inch. Our typical application with 2x 6 walls produces an R-20 cellulose installation, and an R-30 spray foam attic installation.

In the construction process for many homes, tubs, showers, and fireplaces are installed immediately after rough framing is complete and before insulation is installed. As a result, it is almost impossible to properly install insulation and complete air barriers at exterior walls adjoining tubs and showers. This can lead to convective air flow that circumvents insulation.

The installation of air barriers and insulation in these applications at exterior walls can be achieved with proper planning starting with design. Spraying cellulose or placing batts in the wall cavity, and then installing an air barrier, such as ThermoPly, along with installing polyseal, will effectively eliminate the convective air flow. Make sure the air barriers are in place prior to installing tubs, showers, and fireplaces. Another option would be to fill the cavity around the tub with spray-foam, which acts as both a thermal and air barrier. In any of these cases, the tubs will be much less likely to cause comfort or moisture problems.

All HVAC equipment is sized using the Manual J Residential Load Calculations, with a minimum of 600 sf/ton of air conditioning. "Right Size" HVAC systems ensure efficient operation along with using a 15.0 SEER rated system with variable speed condensing units and an Energy Star rated Programmable Thermostat. Greatly oversized equipment operates less efficiently and costs more than properly sized equipment. For example, oversized cooling systems may not dehumidify the air properly, resulting in cool but "clammy" spaces. When using a spray foam or hybrid insulation system, that eliminates attic ventilation, you will need to bring fresh air to the HVAC system to keep the proper pressurization and to help with air balancing. Make sure that your HVAC contractor is well versed in both Manual J and fresh air ventilation. To improve the indoor air quality, we are now installing an Optional Advanced IEQ System. The Trane CleanEffects Air Cleaner that will be installed in our Parade Home is the most effective whole-house air filtration system available.

TRANE CleanEffects

• Removes up to 99.98% of allergens from the filtered air.
  
• Traps particles down to 0.3 microns in size. (A human hair is about 75 microns in diameter.)
  
• Up to 100 times more effective than a standard 1" filter.
  
• Delivers cleaner air and more of it.
  
• Performance has been verified by leading experts at the Harvard School of Public Health
  

All bathrooms and the utility room have Energy Star rated Panasonic Whisper Quiet ventilation fans to reduce energy consumption and noise, while helping eliminate moisture and odors in the homes. We will implement extensive duct leakage testing, blower door testing, and air balancing to maximize the efficiency of the system. You will need to coordinate your HVAC contractor and your third party duct tester to get the proper air flow and balancing specifications. By implementing duct leakage testing and blower door testing, the home eliminates duct leakage to improve air flow and balances it evenly in all areas.

All Green Homes are required to install Zero or Low VOC Paint and Stains, and in addition, we are installing all of our flooring with similar adhesive products. All cabinets are prefinished at the factory in controlled atmospheres that recapture stain and paint waste for recycling, and filter the exhaust from the finishing application.

While there are a few other small factors that can be incorporated to improve Indoor Air Quality, these are what I consider to be the main contributors, and if these are all addressed properly, your home will combine all of the performance characteristics into a unified system.

The Healthiest Housing Markets for 2009

The article below is a portion of the article in Builder Magazine, and the entire article can be seen at http://www.builderonline.com/local-markets/the-healthiest-housing-markets-for-2009.aspx?page=15. I have only included the top 5, instead of the top 15 markets in the nation here. It's good to be alive in Austin, Texas.

Builder, in conjunction with Hanley Wood Market Intelligence, debuts its metric for determining markets with the best and least potential.

By: Boyce Thompson

With most economists and builders expecting a national market decline this year, this may not seem like the best time to be selecting the "healthiest" markets in the country. Virtually every market was down last year. But a close look at the numbers reveals that some markets have way outperformed others during the last four years and are likely to continue to do so this year.

When the housing market stages its official recovery, the markets listed on the following pages are likely to lead the parade. It may take a year or more for the weakest markets--where burgeoning foreclosure sales are still pounding new home values, making building and selling new homes an exercise in futility-- to finally stage a turnaround. We'll present that list next week.

The healthiest markets have many things in common. Most of them are great places to live, either close to the ocean, mountains, or major universities. Most of them didn't have a huge run-up in prices during the boom and aren't experiencing rampant deflation during the bust.

To compile these lists, we analyzed the top 75 housing markets in the country. We ranked them based on population trends and job growth, perennial drivers of housing demand. We also examined what's happened with home prices; many of the healthiest markets have managed to hold the line on home values. And finally, we considered the rate building permits, which may be the single best ongoing indicator of builder confidence in a market. We combined all these metrics to produce a score for each market. Here are the top 5, in reverse order.

The Healthiest Markets for 2009

5. Dallas, Texas

2008 total building permits: 26,145

In a year when permits declined 35 percent nationally, Dallas only experienced a 9 percent fall-off. With a population of 4.3 million, Dallas was the third largest home building market last year, as measured in permits pulled. Employers in Dallas, a popular place for corporate relocation and expansion, added 42,000 jobs last year, a growth rate of 2 percent. Existing-home prices have held steady, falling a paltry 3.4 percent in the last year. Interestingly, the face of residential construction has changed dramatically in Dallas in recent years; 58 percent of the activity last year was in multifamily, compared to a five-year average of 23 percent. The relative stability of the market, though, wasn't enough to prevent Wall Homes from filing for bankruptcy earlier this year. On the other hand, former Meritage co-CEO John Landon recently started a new Dallas-based home building company.

Busiest builders: D.R. Horton, Highland Homes, David Weekely Homes, K.Hovnanian Homes, Drees Custom Homes. Courtesy: Hanley Wood Market Intelligence.

4. San Antonio, Texas

2008 total building permits: 10,261

San Antonio is another Texas market that is still adding jobs, about 18,000 last year. A city of more than 2 million people now, its population is also growing, at a 2.8 percent annual clip through last year. Existing-home prices are barely declining in San Antonio, down less than 1 percent in the last year, to an affordable median price of $152,800, 25 percent below the national average of $200,500, according to the National Association of Realtors. The upper end of the housing market was hurt recently when AT&T announced it would be moving its corporate headquarters to Dallas.

Busiest builders: D.R. Horton, K.B. Home, Centex Homes, Pulte Homes, Fieldstone Communities. Courtesy: Hanley Wood Market Intelligence.

3. Fort Worth, Texas

2008 Total Building Permits: 10,388

Fort Worth, always operating in the shadow of higher profile Dallas, nevertheless can currently claim to have a slightly healthier housing market, based on its employment growth, relatively strong permit activity, and inexpensive housing. Now the 14^th largest home building market in the country, Ft. Worth's builders pulled 10,388 permits last year, roughly two-thirds of them single-family. That may be half as many as 2005, but many other major markets showed much sharper drop-offs. The relative strength of the Fort Worth market in recent years stems from its ties to the oil and gas industries, which has fueled above-average job growth. The metro area added 17,300 jobs last year.

Busiest builders: D.R. Horton, Choice Homes, History Maker Homes, Meritage Homes, Centex Homes. Courtesy: Hanley Wood Market Intelligence.

2. Austin, Texas

2008 Total Building Permits: 14,250

Nine years ago, during the tech bust, some builders felt that Austin was too crowded and left. The bloom is back on Austin's yellow rose now; it moved up the leader board to become the sixth largest home building market last year. Job creation explains the move. While other markets lost employment, Austin added 17,400 jobs last year, 2.3 percent growth rate. It helps that Austin is home to both a major university, The University of Texas, and the state capital. Existing homes cost a little bit more in Austin than other Texas markets, roughly $188,600, but that's still below the national average. Also, Austin is one of the few metro areas in the country where median prices actually rose in 2008--2.7 percent. Amazingly, Austin now generates more home building activity than Chicago, which has six times more people.

Busiest builders: D.R. Horton, Lennar, KB Home, Centex Homes, Meritage Homes. Courtesy: Hanley Wood Market Intelligence.

1. Houston, Texas

2008 Total Building Permits: 42,697

They like to do things big in Houston. Now the metro area, home to more than 5.8 million people, can lay claim to being the largest home building market in the country, with 42,697 building permits. The market is still benefiting from an influx of population and jobs and rebuilding in the wake of Hurricane Ike. Employment was up 2.5 percent last year, representing the addition of an incredible 65,000 jobs. Home building activity in Houston has only fallen 31 percent since 2005. Also, existing-home prices rose in Houston through the first three quarters of last year. They finished the year at a median of $151,600, even with the previous year. Roughly one-third of the home building action is in Harris County, followed by Houston proper and Fort Bend County. One of Houston's largest builders, Royce Homes, shut down last year, and Kimball Hill, one of the biggest builders in Texas,

closed its doors this year after it failed to find a buyer.

Busiest builders: Lennar, Perry Homes, David Weekley Homes, MHI/McGuyer Homebuilders, and KB Home. Courtesy: Hanley Wood Market Intelligence.