Below Grade: RADIANT HEATING
By: Christopher Brooks
When a new home features the best technology for totally green construction, it yields major and long lasting benefits including superior comfort, cost savings and energy efficiency.
Casa Bella Verde, located outside Sacramento, Calif., on 40 acres in El Dorado Hills, is one such residence. Situated on the highest peak in the area, Casa Bella Verde offers a breathtaking 360-degree view.
When completed this will be one of a small number of LEED Platinum homes in the United States and will incorporate the best of all worlds: beauty, sustainability and technology, said Project Director Briana Alhadeff. She is owner of Bella Verde Consulting, a practice of green and sustainable design building consultants based in El Dorado Hills.
Concrete played a major role in the construction of Casa Bella Verde, Alhadeff said. The shell and floor system of the house was constructed entirely out of insulating concrete forms (ICFs). Absolutely nothing compares to the strength and longevity of concrete.
The four-bedroom, five-and-a-half bath main house is 7,500 square feet, and it has an additional pool bath. One bedroom holds the gym equipment; the second will be an office; the third bedroom will be the art studio; and the fourth is a massive master with bath.
Off the backside of the main house is a spectacular half circle vanishing edge pool, which wraps around half of the house. No matter where you are standing, you see water and the spectacular view. Alhadeff said that this is one of the most outstanding architectural features of the home.
Another prominent architectural feature of the home is a 40-foot sky bridge that is suspended 16 feet off of the ground, and connects the main house to a 1,500-square-foot, one-bedroom, one-bath guesthouse.
The homes year-round comfort system is provided by geothermal energy. Alhadeff and her design team chose ultra-high efficiency Tranquility 27 geothermal heat pump units by ClimateMaster, based in Oklahoma City. Three heat pumps were installed " two to serve the main house and one to serve the guest house. †
For the heating season, they chose ClimateMaster water-to-water geothermal units directly tied to the extensive radiant floor heating system manufactured by Watts Radiant Inc. in Springfield, Mo. Several thousand lineal feet of Watts RadiantPEX+ tubing was stapled to the ICF subfloor before pouring the homes insulated concrete floors, which now provide consistent warmth, gently radiating from the floors mass throughout every room in the house.
WATTS RADIANT SYSTEM
The Watts Radiant Heating System was selected because of its quality and ease of installation. Alhadeff said. As for installation, we began our radiant process by carefully designing our zones and tubing length runs. We were careful to make sure that in each run the tubing going to and from the manifold was no more than 300 lineal feet. We then selected the location of each manifold so that they were out of sight, while still easily accessible; i.e. closets, garage, etc. We then placed each manifold in its final location by temporarily mounting it to a board held up by rebar posts, she added. Once the slab is poured, the board will be removed and the rebar will be cut at slab height. The manifold will then be mounted to the newly built wall.
With the manifolds in place, we followed our plan and chalk lined where each run of pipe would be placed. We then laid down the tubing and held it in place on the Insul-Deck ICF flooring system by using Watts staples designed for ICFs. A special staple gun made the installation very simple.
The homes ICF performs at an R50 rating, making it an ideal match for summer cooling using simple fan coils to cool the air with ground source water circulated from the geo-exchange system. Theres no need for chillers or dedicated water-to-air heat pumps.Being in an ICF home, it will naturally stay much cooler than a conventional wood-frame house.
Aside from the amazing architecture of the house, it is constructed entirely green. The structure has no wood. The builder is using IntegraSpec ICFs manufactured by Phil-Insul Corp. in Kingston, Ontario, Canada.
The forms we are using have insulating properties that perform at an R50, Alhadeff said. We will have 95 solar panels on the roof, which will supply the home with a majority, if not all, of the energy that will be required. We will also have a WE Power vertical axis wind turbine, which will be mounted to the roof.
The use of reinforced concrete and use of the ICF forming system has allowed Architectural ICF consultant Nicholas Nikiforuk to design and build an envelope that is extremely energy efficient. It also gave him the freedom to construct magnificent cantilevers, the pool and the sky bridge.
With ICFs, we can insulate concrete structures on both sides, making these (ICFs) truly the most energy efficient and longest lasting structures available to the construction industry, he said. We selected IntegraSpec ICF for our wall system because of its many outstanding features. Because this is a panelized wall system, as opposed to a fixed block, the panels are independent and can be flipped, which makes installation extremely easy with very little wasted material.
Being a LEED Platinum home, these features were very important to us. All building materials that enter this jobsite are either used, reused or recycled. I am proud to say that there is not, and never has been, a dumpster on this jobsite.
Nikiforuk pointed out that one of the unique features of the IntegraSpec panels are their ultra strong inserts. These inserts are used to hold the webs, which hold the ICF panels together. They are made of a high-density polystyrene, which allows the Expanded Polystyrene (EPS) foam to actually fuse with the insert during the manufacturing of the panel.
Because of the strength of these connections, we have confidently poured 12-foot-high walls using an 8-inch slump, Nikiforuk said. This panelized system also allowed us to create tight curves and tapered walls, which would have been extremely difficult with a fixed block system.
Within the concrete used to construct the roof, Alhadeff said she used Krystol Internal Membrane (KIM) manufactured by Kryton in Vancouver, BC, Canada.†When combined with water, KIM reacts with the un-hydrated cement particles to form millions of needle-like crystals that fill in the pores and microscopic voids in the concrete.
KIM is extremely important because it insures that water will never penetrate through the concrete roof, she said. Unlike conventional wood roof systems, the insulated and KIM-treated concrete roof will never be affected by fire, water, termites or storms.
Other green features include an onsite water treatment facility that is designed similar to a small municipal system. Every drop of water that enters the house will be used twice: once for bathing, washing dishes or washing clothes, and then treated and used again for irrigating the landscaping throughout the property.
The house also has an 80,000-gallon cistern for rain water harvesting, which will also be used for irrigation, and for replacing the evaporative loss from the swimming pool. In addition to creating a self-sustaining house, Alhadeff is also incorporating complete home automation into the design, which will include touch screen technology to control lighting, security, whole house audio and video, and heating and cooling.
For the floor system, Nikiforuk said the company selected Insul-Deck ICF based in Safety Harbor, Fla., because of the products strength, insulating properties and built-in utility holes that run throughout, as well as ease of installation. Because all of the Insul-Deck pieces are precision cut to our specifications at the factory, there is absolutely no wasted material, Nikiforuk said.
Casa Bella Verde was designed and engineered so that all of the floors and walls are tied together without any thermal breaks. Alhadeff said this fully insulated thermal mass shell requires very little energy to maintain a desired temperature.
By eliminating thermal breaks in Casa Bella Verdes shell, and making the home truly thermodynamic, we are pioneering a method of home construction that dramatically reduces a homes demand for energy. Multiply that by millions of homes, and you can imagine the strong positive effect this will have on the environment.
Building with insulating concrete forms allows you new creative ways to construct a home in any style. With the many advantages ICFs have to offer youll find it is an ideal choice for construction. Based in Bucks County, Penn., contributing editor Christopher Brooks writes about the home " inside and out " for consumer and trade magazines.