Sustainable North

ASK A BUILDER

By CCHRC Staff

The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.

Q: I am building a house using post and pad construction. Since it will be off the ground, do I need a plastic vapor barrier under the floor?

Post and pad foundations are a common sight in Fairbanks as they represent one of the least expensive approaches to building on unstable soil — of which we have no shortage.

Usually the floor is raised several feet off of the ground and air flows freely underneath.

It is standard practice in cold climate construction to install a vapor retarder on the “warm side” (indoors) of the exterior walls and ceilings. This is done to keep the water vapor generated in the living spaces during the cold seasons from entering the insulated cavities, where it can condense and lead to mold and rot.

Polyethylene plastic sheeting in a “6 mil” thickness is typically used for this purpose, and is mandated by local building codes.

With post and pad construction, it may seem logical to also install plastic sheeting over the tops of the floor joists, before laying down the subfloor sheathing. In some cases however, it can do more harm than good.

If any rainwater leaks through the joints in the subfloor before the roof is on, it will be stopped by the plastic, and the floor may not be able to dry quickly enough to avoid mold and decay. The same risks hold true if liquids are spilled on the floor once the house is finished, or if a major plumbing leak occurs.

The plastic also prevents the use of subfloor adhesive between the joists and sheathing, which is designed to prevent squeaks in the floor.

Modern subfloors are usually sheathed with industrystandard 3/ 4 inch tongue and groove exteriorrated plywood or oriented strand board (OSB).

With post and pad construction, the subfloor sheathings are in an area that is comparatively less at risk for water vapor issues.

This is due in part because warm indoor air leaves at the top and is replaced by outside air drawn in at the bottom, so water vapor moves upwards — away from the floor.

In addition, the combination of thickness and types of glues used in 3/ 4inch plywood and OSB subfloor sheathings means they are less likely to absorb any moisture that might be forced into the house.

To minimize air leakage through the floor, the unsupported seams can be caulked with an adhesive sealant such as a silicone that is rated to have a good bond strength with wood.

The decision of whether to use or omit a plastic vapor retarder in floors using post and pad construction ultimately rests with the engineer or the local code official who may have reasons specific to the project or building site.

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, email us at akhomewise@cchrc.org.You can also call the CCHRC at (907) 457-3454.

From The Fairbanks Daily Newsminer, Thursday, July 29, 2010:

A plan to transfer Fairbanks Natural Gas LLC from private to public ownership and truck liquefied natural gas to Fairbanks from the North Slope is doomed, according to an Alaska Gasline Port Authority board member.

Board member Merrick Peirce wrote in an e-mail that the assumption behind the $250 million business deal — that crude oil prices will continue to rise — is flawed because more crude oil production is coming online in Iraq, increasing the world’s supply.

In interviews, other port authority board members defended the plan and refuted Peirce’s claims. They said the proposal, to be financed with bonds, provides the best possibility of quickly lowering energy prices in Fairbanks.

Decades of talk about building a natural gas pipeline have yet to produce results. “We have not given up on the pipeline,” said Dave Cobb, Valdez Councilman and vice chairman of the port authority governing board. “That is still our No. 1 priority, but you have to do something in the interim.”

The port authority is a partnership between the Fairbanks borough and the city of Valdez that was created to build a gas pipeline to Valdez. Peirce offered his criticism in an e-mail to the Fairbanks North Star Borough Assembly, which tonight considers a resolution to accept the authority’s proposed purchase of Fairbanks Natural Gas. The assembly also will consider an ordinance that would require a public vote to broaden the port authority’s mission statement before it goes ahead with the trucking plan.

Continue reading: Criticism mounts for call to truck liquefied natural gas to Fairbanks

From the US Dept. of Energy:

The size of new U.S. single-family homes completed in 2009 declined, dropping to a nationwide average of 2,438 square feet and reversing trend of the past three decades, according to a National Association of Home Builders (NAHB). New single-family homes were almost 100 square feet smaller in 2009 than they were in 2007, according to recently released U.S. Census Bureau data. One reason for the drop, NAHB noted, was homeowners’ desire to keep energy costs in check. This growing energy-efficiency consciousness is one of many trends that the association said was likely to continue.

Continue reading: Report: Home Size is Declining, Energy Efficiency a Factor

From The New York Times, Wednesday, July 28, 2010:

With a cap on carbon dioxide an apparent nonstarter in the Senate these days, some clean energy and climate advocates have shifted their sights to a scaled-back but still ambitious goal: passage of a national renewable electricity standard.

Such a law would require utility companies to produce a set amount of electricity from renewable sources by a certain date, spurring the development of clean sources like wind and solar and probably lowering overall emissions nationally. Perhaps most important, some argue that with a strong push by the president, such a measure could actually clear the high bar for passage of 60 votes in the Senate this fall.

Continue reading: A Push for Action on Renewables

From The Fairbanks Daily News-Miner, Wednesday, July 28, 2010:

Fairbanks businessman Bernie Karl said a decision to transport oil-spill supplies to the Gulf Coast six weeks ago appears to be paying off.

Karl, who owns Chena Hot Springs Resort, Chena Power and K&K Recycling, made an expensive gamble to be part of the ongoing cleanup operation.

With crude from the damaged Deepwater Horizon offshore oil rig steadily flowing into the Gulf of Mexico, he said he shipped 11 truckloads of equipment from North Pole to the Gulf Coast, at a cost of about $18,000 per load.

From Natural Resources Defense Council, nrdc.org:

Use these ideas to help turn any space into a stylish, inviting and eco-friendly venue, whether you’re remodeling a home or designing for a special event.

1. Decorate with Plants

Plants can act as natural air filters, removing harmful chemicals like benzene and carbon monoxide from the indoor air. And they look great too, giving your home a more natural and vibrant feel. The best plants for improving indoor air quality include the peace lily, bamboo palm and gerbera daisy.

2. Maximize Daylight

Maximizing daylight — through skylights, open shades, and south-facing windows — substitutes electrical lighting with the natural light of the sun, saving money and preventing the emission of air pollutants and greenhouse gasses.

3. Use Energy Efficient Lighting

Compact fluorescent light (CFL) bulbs use a third of the energy of regular incandescent bulbs and last up to ten times longer. Replacing a traditional incandescent bulb with a CFL can save you more than $30 over the lifetime of the bulb and prevent the emission of air pollutants and greenhouse gases that contribute to global warming. Look for the Energy Star label.

4. Choose FSC Wood Products

Much of the wood that we buy comes from unsustainable operations in endangered forests, including the Canadian Boreal, Cumberland Plateau, and the rainforests of Borneo. The Forest Stewardship Council (FSC) is the only credible international certification organization for sustainably harvested wood and wood products. Look for the FSC label.

5. Select Efficient Windows

Windows are a significant source of heat loss in the winter and unwanted heat in the summer. Energy-efficient windows are lined with special coatings that reflect heat and provide superior insulation, keeping your home warmer in the winter and cooler in the summer. Efficient windows save money on reduced heating and cooling bills and prevent the emission of greenhouse gases. Look for the Energy Star label.

6. Opt for Low VOC Products

Many common household products, including paints, carpets and furniture, emit volatile organic compounds (VOCs) that can be harmful to human health. When buying these products, look for those with a low VOC content.

7. Buy Locally

Locally produced products travel fewer miles to their end destination, resulting in less air and global warming pollution from transportation.

From Thedailygreen.com:

When you think of sustainable dining, you probably don’t think of fast-food restaurants like Subway, Starbucks and Chipotle. And yet, these fast food chains are some of the few who have successfully pursued LEED certification.

LEED stands for Leadership in Energy and Environmental Design and is an internationally recognized third-party certification that a building meets high standards for energy savings, water efficiency, emissions reduction and improved environmental quality.

So far, only 38 restaurants have received LEED certification — and a shocking 40 percent of those are chain restaurants. For many of these large chain organizations, LEED certification is a relatively cost efficient way for not particularly green companies to flex their corporate social responsibility muscles.

One surprise on the list: sandwich chain Subway currently has one LEED certified restaurant in Chapel Hill, NC. “We believe that building stores in an environmentally responsible way is a good business practice,” says Subway’s public relations specialist Les Winograd.

Read on for more LEED-certified fast food chains — as well as some independent restaurants that are taking the LEED leap.

Continue reading: 9 Surprising LEED-Certified Restaurants

From The Associated Press, Thursday, July 22, 2o1o:

Alaska Airlines says it’s flown another test flight of landing procedures at Seattle-Tacoma International Airport that can save fuel, reduce noise and cut emissions by a third.

The procedures, already used in Alaska and at several Lower 48 airports, use satellite technology to guide a plane to a landing. That permits the aircraft to fly a shorter, more direct and slower approach.

Alaska Airlines is working with the Port of Seattle, Boeing and other airlines to get Federal Aviation Administration approval to use the techniques at Sea-Tac. If so, Alaska Airlines estimates that more than 2 million gallons of fuel could be saved each year. The project began last summer, and this week’s test involved a 737 jetliner making eight approaches to the airport.

From The Anchorage Daily News, Friday, July 23, 2010:

Thanks to clever marketers, if I said I had a problem with ED, you might immediately have an idea what I’m talking about. But I have a problem with EE. It’s no cause for embarrassment — EE is a great thing. EE can save you money, create jobs, help protect our environment and safeguard our children’s future. Unfortunately, many people just don’t find EE that exciting.

EE is energy efficiency, and if you’re a building or business owner you needed EE yesterday. It’s the cheapest way to boost your profit margin, and in these tough times who doesn’t want that?

Oil spewing in the Gulf presents yet another reminder of our unsustainable addiction to fossil fuels, amplifying calls to move toward “clean” energy systems. Energy costs in Alaska can stifle economic development, especially in rural areas. Renewable energy generation — wind, solar, hydro, geothermal — is crucial to Alaska’s clean energy future, and this is what most people think of first when looking for truly sustainable energy solutions.

Continue reading: Perhaps energy efficiency needs sex appeal

From The Associated Press, Thursday, July 22, 2010:

Salmon processed at a Kodiak plant will be getting a new tag.

Island Seafoods plans to tout the plant’s connection with sustainable energy on a new label.

General manager John Whiddon tells the Kodiak Daily Mirror it may say, “sustainable fish produced by clean, sustainable wind turbine energy.”

Island Seafoods uses power that’s produced in part by Kodiak Electric Association’s Pillar Mountain wind turbines.

The utility began using the three 1.5 megawatt turbines last summer. They have saved the utility more than 900,000 gallons of diesel fuel.

The utility’s president, Darron Scott, suggested the joint marketing agreement with Island Seafoods.