“Double-stud walls, that is. On a recent trip to Denver, some net-zero energy production homes caught the Mystery Inspector off guard.”
By Dan Morrison
November 04, 2013
I was in Denver a couple of weeks ago scouting out the housing situation and was very pleased with what I saw. In looking at background research of the home building market, I noticed that Stapleton is the biggest and most active development in the county, so I focused my short time in the area investigating that development.
The first thing that struck me was the quality of design in all of the houses. These are not cookie-cutter boxes like I see in so many other housing developments around the country—these are beautifully designed homes with classic and modern lines. Single-family and townhouses are mixed together in a vibrant, walkable community with plenty of joggers, kids, and dogs.
After driving around for 20 minutes, I decided to tour some model homes. I started with townhouses built by New Town Builders. New Town offers three levels of affordability in their townhouses, so I looked at all three.
The trim details were the first thing I noticed inside the house. No clamshell and speed base, this was actual 3-piece head casings and wide side casings on the doors. Attaboy, designer!
I walked upstairs to the main living floor and entered the kitchen portion of the open plan living space. It is very common to combine kitchen, dining, and living areas into one open space, and that is the case in all of the homes I toured at Stapleton.
The finishes are high quality: wood cabinets, stainless steel appliances, granite counters, tile backsplashes, and wood or tile floors. All units have first- and second-floor outdoor living space.
Energy efficiency is included. Because Denver has adopted the most recent version of the energy code, the 2012 IECC, all of these houses are energy efficient and presumably well-constructed. But to be sure, I had to look a little deeper.
First, I checked out the mechanicals in the finished units. What I found in the utility closet was a power vented sealed-combustion water heater with an extremely high-energy efficiency rating. Under the water heater is a stainless steel overflow pan with a floor drain in case of emergency. The floor drain is vented with an air admittance valve (AAV), which is a great option because it saves a lot of PVC pipe and reduces the number of holes needed in the roof. Attaboy, plumber!
The furnace also is high efficiency, with an annual fuel utilization efficiency of 92. But the energy rating is a moot point if the ductwork is leaky. These ducts, however, are sealed with mastic. Attaboy, HVAC guy!
After talking to one of the sales reps I learned that there are some zero-energy homes being built a little farther north, so I drove up to have a peek.
First impression: Nice open plan, great finishes. Both of these are good things. Because Denver throughout the year is either cold and snowy or cold and muddy, these houses have a mudroom off the rear entry. The mudroom has cubbies for kids, a mini home office, and a pantry for Costco shoppers. Off the mudroom is the kitchen, dining, and living zone, which includes high-quality finishes and appliances, and a family-friendly layout.
But I didn’t come to look at kitchens and mudrooms. I came to dig deeper under the hood of how these homes are built. Turns out, I got quite a surprise.
Rather than sneak into a house under construction after hours, like I usually do, I took the diplomatic approach: I asked permission from the sales guy in the model home. Bill Gleeson agreed on the condition that I let him give me a quick tour of the building science exhibit. I learned about New Town’s commitment to building science, energy efficiency, indoor air quality, and money savings through smart design.
When he talked about wall construction, my jaw dropped. Double stud construction—really? I recently talked to a green builder who has had tremendous difficulty getting framing crews just to frame on 24-inch centers rather than 16-inch centers. These folks are framing double walls on 24-inch centers. Moreover, they’re splitting the bearing between the two: floors bear on the interior wall, the roof bears on the exterior wall. Production framers doing high-performance building—I’ll need to dig into that a little more in the future.
Printed framing plans are available on the jobsite for the framers to follow along with particular details for inside and outside corners, intersection walls, and top plate splices—did I mention that they’re doing single top plates?
The window framing, often a trouble spot with double stud walls, looked clean.
Practically drunk with pleasure, I went upstairs to see if there was anything else that could make my day any better; and there was: soffits done right.
When bath fans were hidden in an interior soffit, there was a fire-taped drywall air barrier so that the soffit and fan were not connecting interior with exterior. This is important from an energy efficiency standpoint, an indoor air quality standpoint, and a durability standpoint. If not properly sealed, the soffit represents a huge connection to the insulation cavities and a direct pathway to the outside, which wastes energy. If the ductwork is running through cold walls or ceilings, the steam that it’s carrying will condense to water and can promote mold growth.
You may have noticed that I have not talked about high-performance bling yet even though we are talking about a zero-energy home. These houses do indeed have PV panels on the roof, but New Town does all of the right things first: tight construction, super insulation, super efficient windows (with a U-factor of 0.25), and an air-source heat pump. After that, they add photovoltaic panels to provide the electricity.
Overall, I have to award New Town Builders with a huge attaboy for kicking butt, taking names, raising the bar, and delivering tons of value to its customers.
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