Earth Advantage Article about Miranda Homes

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Green Engineered: The Miranda Homes' Way
March 30, 2010

You're a new homebuyer. Imagine hearing the builder say, "Construction is set to begin tomorrow. In 45 days, you can move into your new house. And by the way, it will achieve the highest level of green certification." Yes, you heard right: 45 days. You could be living in a brand new, green-certified home in less than two months. Most people cannot find an apartment to rent in such little time. Thanks to new thinking and existing production capabilities, Miranda Homes is changing the face-and building schedule-of new home construction.

The concept for Miranda Homes was sparked several years ago when its owner, Rob Boydstun, also owner of Boydstun Metal Works, started exploring new ways to use his company's existing materials and machinery. "The initial idea was to use our machine shops to build roll-forming machines to make steel studs. But after studying the entire value stream of building homes, we determined that steel studs alone were not the answer to improving housing," recalls Mark Mecklem, VP of Sales and Marketing for Miranda Homes. It was time for a fresh start.

The first step in improving traditional home construction came in the form of a panelized wall system. Traditional framing practices cause excessive jobsite waste, allow insulation voids, and are susceptible to insects and the elements. Miranda Homes' 100% recycled, steel-framed panelized wall systems are produced with minimal waste, will last forever, and are not affected by moisture or pests. The wall panels are shipped to the jobsite and assembled in just one day.

The only problem with steel frames is that metal conducts heat and cold more than wood, so it is more susceptible to thermal bridging than a wood framed house. Thermal bridging is the loss of heating or cooling through the uninsulated studs. Miranda Homes solves this issue with insulation. The panelized wall systems are assembled with plywood sheathing and a layer of external, rigid foam insulation. Once assembled at the jobsite, spray-foam insulation is applied to the walls. Spray-foam insulation has the highest R-Value of all the types of insulation and it forms a complete seal in the wall cavity.

Another cause of heating/cooling loss is a home's foundation. To prevent this problem, Miranda Homes insulates the slab of the foundation and uses insulated concrete forms (ICFs) to create insulated foundation walls. This system, called a "mechanically vented crawlspace," improves a home's efficiency by eliminating passive vents and keeping any heating/cooling loss from hot water piping and ductwork from escaping. Additionally, Miranda Homes pours the entire foundation in just one day. This practice reduces waste, creates a stronger foundation, and cuts labor costs by two-thirds.

A complimentary step to insulation is air sealing. The more tightly sealed a home is, the less it is going to leak heated or cooled air. Blower door tests are the industry standard for evaluating how efficiently a home is sealed. To qualify for ENERGY STAR® certification and Earth Advantage® certification, a home must test less than 7 air changes per hour (ACH). On average, an Earth Advantage certified home tests between 6 - 6.5 ACH. A score of 2 - 3 ACH is considered excellent. Recently, a blower door test performed on a Miranda Home recorded a 1.5 ACH, but this wasn't good enough. "We identified some problem areas and sealed them up," says Mecklem.

Earth Advantage returned to the home for a follow-up blower door test. The result: a jaw-dropping 0.6 ACH. "I couldn't believe it," says MacKenzie Winchell, the Earth Advantage residential technical specialist who performed the test. "I retested it two more times to make sure the test was accurate."

The blower door test not only confirmed that the Miranda Homes' system is working, but that it is working incredibly well. For them, it's really just another step in the right direction. The company is constantly looking for ways to improve. To date, Miranda has made improvements to the truss system, air sealing, and whole house ventilation systems. In fact, every essential mechanical system (i.e., plumbing, HVAC) is carefully pre-engineered. The company's process has been refined to six distinct phases of construction and Miranda Homes only uses a select few subcontractors, reducing costs, eliminating delays, and improving the quality and efficiency of each home.

While some established builders seek reasons not to change, Miranda Homes embraces change and improves on it. The future for the company looks bright. Currently in the middle of constructing its fourth home, Miranda Homes offers seven floor plans and is developing the eighth. Additionally, according to Mecklem, "Miranda Homes is always researching new products to see how they fit into our building principles and methods. We're looking for products that improve safety for our people, reduce impact on the environment, and increase the quality, monthly savings, and longevity of our homes for the homeowners." Don't be surprised if you hear about a 30-day house in a couple of years.

Mark Mecklem - Miranda Homes