Dallas Air Tight Homes
If you’re in the market for your next home, or perhaps your first, you have plenty on your plate to think about. There’s the neighborhood, the size, your new mortgage, your credit, and on and on the list goes. If your next home is a new construction, that list of factors to consider doubles. Nonetheless, new home construction is always an exciting venture. When you’re next home is not only something picked out by you and only you, but is specifically built tailored to your wants and needs, the sky is truly the limit. As much as finding an existing home for sale in Dallas that’s just perfect for you is exciting in its own right, there’s nothing quite like having one built from scratch.
And one aspect of this new construction home in Dallas you might want to take extra care to consider is the envelope. That refers to the air barrier of the home, or the air seal. In this article read on to learn a thing or two about the idea of air tight homes, what the point is, how it’s done, and potential drawbacks and considerations to make. This is all about insulation so we’ll be talking a lot about energy efficiency, ventilation, and air circulation in the home and how that relates to your overall experience as a new homeowner in Dallas.
What is an Air Tight Home
When we refer to an air tight home construction, really what we mean is a home that’s designed and built specifically with air sealing in mind. Air sealing means that to the extent that it can be done, all the gaps and places where air can leak in and out of the home have been taken care of. This creates a home that is incredibly energy efficiency and that’s a huge plus when living in an energy-hungry area like Dallas.
Minimizing air movement in and out of a house is key to having an energy efficient home. Controlling air leakage is also critical to moisture control. These leaks also may result in poor indoor air quality inside your home. Poor indoor air quality can lead to all kinds of health issues including headaches, nausea, asthma, upper respiratory infections and trouble breathing, so there are ramifications beyond just your energy bills. It’s a matter of comfort as well. Air sealing a house increases your comfort by reducing the drafts in a house
Now, it’s important to note that air tight homes aren’t a new idea. It’s something that home development in general has been steadily moving toward as home building technology and materials get better. Without a doubt, modern construction practices have resulted in houses that are much tighter than those built a hundred years ago. One of the reasons for this evolving tightness is the use of sheet materials, with drywall and plywood, there are fewer random holes for air to pass through. Plus, windows and doors continue to improve. Today, virtually all manufacturers make products that seal very tightly.
With tight construction, healthy materials, controlled ventilation, and direct-vent, sealed-combustion heating devices, you can have a tight house and good indoor air quality. If you consider a house to be a system, tight construction has many advantages over loose construction. Most building scientists are of the opinion that tighter houses are an excellent idea, and the tighter the better.
How It’s Done
So, what are these materials and techniques used in the construction of an air tight home? Well, that’s a big question, so let’s jump into it. The biggest thing to focus on when making an air tight home is insulation.
One big part of this is a continuous air barrier from the basement slab to the attic floor. That means the basement slab to the basement walls needs to be air sealed. The foundation to the floor system needs to be air sealed, whether through house wrap or another material; and the walls to the attic floor need to be air sealed.
What is house wrap? It’s the most common air barrier material. It is wrapped around the exterior of a house during construction. Wraps usually consist of fibrous spun polyolefin plastic, which is matted into sheets and rolled up for shipping. House wraps may also have other materials woven or bonded to them to help resist tearing. Sealing house wrap joints with tape improves the wrap's performance by about 20%. All house wrap manufacturers have a special tape for this purpose.
Air barrier is a phase you’ll hear a lot when looking into air tight construction. Air barriers block random air movement through building cavities. As a result, they help prevent air leakage into and out of your home, which can account for 30% or more of a home's heating and cooling costs. Although they stop most air movement, air barriers are not necessarily vapor barriers. The placement of air and vapor barriers in a structure is climate-dependent, and it’s wise to work with building professionals familiar with energy efficient construction in your area.
But creating an air tight home starts even before insulation materials are looked at. It starts as early as the framing stage. Good structural design means less framing costs and more room for insulation in the shell. A common leakage point in houses is the small gap formed where a wall meets the floor. This can be solved with bead of caulking, or a special gasket, placed on the subfloor before the wall frame is even erected. Once this is done by the framing crew, the wiring, plumbing, insulation, etc., are installed in a conventional manner.
When it comes to the walls themselves, there are two main techniques used to achieve air tightness. These two wall construction techniques, the airtight drywall approach (ADA) and simple caulk and seal (SCS), can be used to create a continuous air barrier within a house. Using one of these techniques can significantly reduce air leakage to help improve a home's energy efficiency.
The typical procedure for ADA is to seal seams, joints, and openings in the building envelope during construction. SCS is less disruptive to the construction process because seams and gaps are sealed after the exterior sheathing and drywall have been installed and finished. However, SCS is less comprehensive than ADA, and may miss some critical points inside building cavities that become inaccessible after the drywall is installed. Tests on ADA- and SCS-detailed homes indicate similar energy savings. For health and safety, a heat or energy recovery ventilator should be installed in an airtight home for proper ventilation.
What If It’s Too Tight
There’s another question that often enters this discussion on air tight homes. That question is whether it’s possible for the home to be sealed too tight. The overarching worry here is that a home that’s too tightly air sealed will have insufficient ventilation and ultimately this will lower indoor air quality.
As big a worry as this sounds, it’s misplaced. So let’s take these issues one at a time. The “too tight” theory holds that houses need to breathe. Traditionalists can point to old houses and claim the only reason they’re still standing is because air leaks amount to natural ventilation that dries everything out and keeps the house healthy.
In reality, air leaks mean you’ve lost control of air movement. Tight houses solve a lot of problems that homes with air leaks have, and the only caveat is that you need mechanical ventilation to ensure a supply of fresh air to keep people healthy; and existing houses should not be tightened without assessing whether the existing combustion appliances have an adequate source of combustion makeup air.
These common misconceptions about air tight homes, problems of poor indoor air quality, moisture, and poor chimney function, are typically not due to tightness itself, but rather a failure to view a house as a system. You can build tight buildings as long as you don’t fill them with unhealthy materials. Fortunately there are ways of achieving energy efficiency without sacrificing health.
As far as insulation goes, there may be a theoretical point of “too much,” but in most cases buildings have too little. At the very minimum, insulation should meet recommendations of the Department of Energy, but adding more is always a good thing. Properly insulated buildings are cheaper to heat and cool.
Where insulation is added can be as important to how much is added. Walls and roofs with an extra layer of rigid insulation outside the framing help cut energy losses due to thermal bridging. What’s more, some types of insulation are inherently more effective than others. But using too much should be the least of your worries.
New Air Sealed Homes and Dallas Realtors
Want a better home experience? Consider making the air seal of your next home a priority. And to boot, this stuff applies to existing homes in the Dallas real estate market as well as new construction. As a homeowner in Dallas, you can always make improvements to your home’s insulation and get more bang for your buck. And don’t forget, if you’re just starting your journey to homeownership, there’s no greater tool at your disposal than an experienced Dallas real estate agent. Call or contact us today and get started on your Dallas home shopping journey and live and love your home!
Author: Candie Hernandez
December 4th 2017
About Candie: Although not originally from Texas, it has become my home after 30+ years of living primarily in the...