Category Archives: Building Structure

Taking the chill out of Arctic homes

From The Arctic Sounder, Wednesday, August 25, 2010:

The success of an innovative new home in Anaktuvuk Pass – which uses a wind power, solar panels and design features of traditional Nunamiut sod housing – is changing the way houses will be designed and built on the North Slope.

“This is a huge leap forward – I hope it has tremendous impact,” said Daryl Kooley, of the Tagiugmiullu Nunamiullu Housing Authority.

The house used just 87 gallons of heating fuel from November to June. Other homes typically use about 100 gallons of fuel per month.

It also cost a lot less to build – just $220,000, compared to a normal three-bedroom home in Anaktuvuk Pass, which runs upwards of $570,000.

The house was the prototype in an effort to find ways of building better, more cost-effective houses in rural Alaska, which “grew out of the fact that estimates for new housing were so extraordinary,” Kooley said. A modest, three-bedroom home in Nuiqsut constructed in the usual way, for example, can cost over $1 million to build.

That is a real problem in North Slope villages, which suffer over-crowded, crumbling homes in desperate need of replacement. To find a solution, TNHA teamed up with the Cold Climate Housing Research Center, a nonprofit that works on developing housing designs for the circumpolar north.

“We are going to have diminishing financial resources for building in rural Alaska given the economic reality of the U.S. So how can we together address the high cost of housing? We can do that together so the future is a little brighter for these communities,” said CCHRC president and CEO Jack Hebert.

The Anaktuvuk Pass prototype house was the first structure built as part of CCHRC’s Sustainable Northern Communities project, a program begun in 2008 to engineer housing solutions for rural northern communities.

Continue reading: Taking the chill out of Arctic Homes

Hot water flooring has its advantages

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: What are the advantages of hot water infloor heat versus baseboard heating?

Radiant hot water (hydronic) floor heating systems’ costs are usually higher than baseboards, however they offer significant performance advantages.

The typical hydronic floor heating system consists of tubing installed in a looping pattern in the floor. This arrangement is specifically sized and spaced to release a given amount of heat from the hot water flowing through the tubes.

There are two primary types of installations, “wet” and “dry.” A “wet” system also is known as “slab heating” and involves embedding the tubing in a poured concrete or gypsum floor. “Dry” systems route the tubing either under or on top of an existing wood subfloor.

Depending on the insulative properties of the floor covering (such as carpet), dry systems may need to operate at higher temperatures to perform comparably to wet systems.

With both types of systems, insulation is often added under the tubing to insure that most of the floor heat travels in the desired direction, rather than into the soils around the foundation.

One of the biggest arguments in favor of in-floor heat is the comfort level. With such a large surface area emitting radiant heat very evenly, most occupants with warm floors tend to feel more comfortable even if the air temperatures are slightly cooler, which in turn may lead to lower thermostat settings.

From the energy savings perspective, hydronic floor heating runs significantly cooler than hot water baseboards.

For instance, the water temperatures in the tubing running through a concrete slab usually range between 80 and 130 degrees F while baseboards operate between 130 and 165 degrees F. Usually, the lower water temperatures needed for slab heating allow the boiler to run cooler.

A cooler running boiler has several advantages, such as less heat loss up the chimney when the boiler is in an off cycle. Similarly, the boiler has less “jacket loss,” where heat is lost from the boiler to the room Cooler water heating can also make the best use of a condensing boiler, which can operate at lower temperatures and generate efficiencies of up to 94 percent.

Conventional boilers top at around 87 percent. When it comes to conventional boilers, cooler operating temperatures produce less system stress, which can extend the service life of certain boilers.

Although the initial costs are higher, the longterm benefits of hydronic floor heating are worthy of consideration, and can also contribute to the value of the home.

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

A material’s ability to absorb heat is separate from conduction

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 hear that log and concrete walls have the added benefit of “thermal mass.” How much of a difference does it make?

The basic concept of thermal mass revolves around a materials ability to retain heat. Logs, stone, and concrete all have the capacity to store significant amounts heat. When denser materials such as logs are used to build exterior walls, they will perform differently than your standard “light frame” construction which uses wood studs and fiberglass, as the logs will store more heat. It is not that simple however, as other material properties come into play as well.

Large logs also have some insulating value, whereas a material such as concrete will store heat well, but will also readily conduct heat. This changes when concrete is combined with insulation, such as an insulated concrete form (ICF) which sandwiches the concrete between two layers of rigid foam board. The extra insulation improves the ability to of the concrete to retain heat dramatically.

This is an important concept. A material may be able to absorb large amounts of heat, however if its insulative properties are low, it will just as readily conduct that heat through the wall.

In a Fairbanks winter, the path of heat flow is always in one direction, from inside to outside. This means that the heat absorbed by the mass in the exterior walls is from the inside and is still heat you are paying for. On the other hand, in climates where there is a lot of solar heat during the day, properly applied thermal mass can store some of this heat during the night. On the bright side, if the power goes out, or you are heating with wood and the fire dies down, then the room will stay warmer for a longer period as the walls provide a buffer due to the extra heat energy they contain.

Q: I noticed the screws holding down my metal roofing have backed out in places, why is that?

If the screws were not over tightened or stripped when they were put in, and are of the right type, then it is possible there are other causes. Metal roofs experience large, fast shifts in temperature, much more so than the wood underneath.

As the metal expands and contracts it exerts stress on the fasteners, particularly on a large roof. Sometimes with temperature swings, you can hear it moving. If the screws are small, this can also play a role. Upsiz-ing to a larger screw in the troublesome area usually solves this problem.

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, email us at akhome-wise@cchrc.org

Know your home rebates

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: Many people are fixing their old home and getting a rebate from the state. Is there still rebate money available for building a new home?

The statesponsored Energy Rebate Program for new construction is still active, although continuous longterm funding is uncertain. Any homeowner who builds a home that meets the Alaska Housing Finance Corporation (AHFC) 5Star Plus energy standards is eligible for a $7,500 rebate, however there are some important details that determine who qualifies and a specific process that must be followed.

The program operates from a statewide waiting list on a firstcome, firstserved basis. So the sooner you sign up, the better your chances are for benefiting from the program. The first step is to get on the waiting list. Locally, the staff of CCHRC’s Portal on Retrofits Training and Loans (PORTAL) can guide you every step of the way.

Call 455HEAT (4-328) or contact the AK Rebate Call Center tollfree at1-877AKREBATE (1-877-257-3-228). Once your name reaches the top of the list, AHFC sends out two forms: “5 Star Plus New Construction Energy Rebate Encumbrance Request” and the “5 Star Plus New Construction Energy Rebate Form.” As an ownerbuilder, when you submit the completed forms, you must also include a copy of an energy rating taken from the building plans that validates that the home will meet 5 Star Plus standards, which can be found on the AHFC website: www. ahfc. state.

ak. us. Once AHFC receives and approves the forms, $7,500 is set aside for one year during which the house must be completed.

There are several criteria to meet to be eligible for the program.

Only the original owner qualifies for the rebate, and the home must serve as the primary residence.

If the home is purchased from a builder, it cannot be more than one year old at the time of the first sale. Ownerbuilders can qualify too, however the home cannot be occupied for more than one year from the date of completion.

To qualify if you are an ownerbuilder , you will have to submit the right forms to the state once the home has been completed. These forms include the “Building Energy Efficiency Standard Certification (BEES),” which certifies that the home was built to meet the 5 star Plus thermal and ventilation standards. The form can be signed by a certified home inspector , engineer , energy rater , architect, or the builder if he/ she is approved to certify and has met the current BEES training and testing requirements.

A “Summary of Building Inspection” form must also be submitted, which validates that the home was built in compliance with local building codes. This form must be signed by a statecertified building inspector who has conducted all the inspections during the construction process, starting with the building’s footings. For this reason, it is important to begin the rebate process and hire an inspector before breaking ground on the home. Finally , the finished home must also have an energy audit.

These three forms must be completed, signed by the appropriate authorities, and submitted to AHFC with the reimbursement form. Although this process may sound complicated, the new home construction rebate is a great opportunity for an ownerbuilder or new homebuyer to offset a significant portion of the construction costs, and ultimately enjoy the long term financial and environmental benefits of building an energy efficient home.

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 (9-07) 457-3-454.

Excellent insulation is the way to go in Alaska

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 want to put insulation on the outside of my home before winter. I heard it has to be applied in the right ratio. What does that mean?

At CCHRC, we receive many questions from property owners who are interested in retrofitting homes with additional insulation. This can make a big difference in heating costs since it cuts down on heat loss through the framing and also due to air leakage. Adding exterior insulation will influence how the home performs in other ways too, as a home with less air leakage often accumulates more humidity indoors during the winter.

Most framed homes in Alaska contain plastic sheeting behind the drywall. This sheeting is designed to keep the water vapor generated indoors from condensing inside the walls and ceilings during winter. The plastic sheeting is rarely perfect, particularly in older homes, and some moisture may collect inside walls during winter. Usually the walls will dry out in the summer, as moisture can still exit through the outside of the wall. If rigid foam board is added to the exterior, this can make it difficult for the wall to dry out.

The best approach is to add enough exterior insulation so that the existing wall never cools to the point that condensation forms. Determining the proper amount of exterior insulation required to eliminate moisture problems inside the wall depends on local winter temperatures and the original amount of insulation in the wall. Generally accepted formulas for the Fairbanks area say that a house with 2-x-6-inch walls should have between 6 and 11 inches of exterior foam board (depending on the type) to compensate for the insulative effect of the existing insulation. Unfortunately, this much exterior insulation is often expensive.

If not enough exterior insulation is added to keep the existing wall warm enough, controlling indoor humidity through mechanical ventilation becomes extremely important to reduce the potential for moisture problems inside the wall. In Interior Alaska’s dry climate, a properly sized and installed ventilation system can readily reduce indoor humidity levels to 20 percent. Windows can provide a visual indicator of moisture issues when they attract condensation, however an inexpensive indoor humidity monitor would be more accurate. Monitors can be obtained through local supply houses or on line.

Exterior insulation retrofits can result in big energy savings, however, each home needs to be assessed on an individual basis. Local climate, variations in existing wall construction, occupant awareness, mechanical ventilation, and the materials and methods used in the retrofit all need to be taken into consideration to maximize performance and minimize risk. CCHRC is conducting research on exterior insulation retrofits under best and worst case scenarios for indoor humidity. These results will be published at the conclusion of the experiments.

University of Alaska Fairbanks summer class learns new log construction technique

From The Fairbanks Daily News-Miner, Friday, July 30, 2010:

FAIRBANKS — Most sheds aren’t much to look at. But the new cordwood garden shed at the Georgeson Botanical Gardens could almost pass for a Victorian stone building from afar, sitting on a hill among a riot of red and pink poppies and giant sunflowers.

It was actually built of recycled telephone poles by 16 students taking a cordwood masonry workshop through the University of Alaska Fairbanks summer session.

The 8-by-8 foot frame was filled with about 20 workers constructing walls out of logs, mortar and sawdust. The walls stood about one foot wide and two feet high Wednesday afternoon. Cordwood masonry uses mortar to cement together short, round pieces of wood — like firewood — with their ends pointing out, incorporating creative patterns and mixed materials.

“Most people haven’t heard of it, but it’s been around for hundreds of years,” said Rob Roy, who taught the class with his wife Jaki. The couple owns a green building school in upstate New York. They have built multiple cordwood homes and teach workshops around the country. Roy, who gave a talk Monday at UAF on affordable home ownership, promotes cordwood masonry as a sustainable, low-cost and creative style of architecture.

Using recycled materials is one way to lower costs and environmental impact.

Continue reading: University of Alaska Fairbanks summer class learns new log construction technique

Think vapor barrier when going post and pad

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.

9 Surprising LEED-Certified Restaurants

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

An unlevel house can cause a number of problems in the home

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: My home is starting to settle a little bit. What advice can you give on leveling a house?

What is an acceptable amount of settling is a relative question, but if windows and doors start to bind that is a good sign that things have gone too far. Plumbing systems can also be at risk for damage and are often overlooked until it is too late.

One option to level a home is to use hydraulic bottle jacks.

If you can get under the beams that support the house and raise them with bottle jacks, that is a fairly inexpensive route to take.

Some home moving companies and contractors will have airbags that they gradually inflate under the home. As the building comes to level, they will add more structural support to the structure. This approach works well on soft soils. One older method involves a railroad jack, which relies on a mechanical ratcheting system instead of hydraulics.

This device can fit into a four-inch space, making it very handy. A few of the rental stores in town still have this jack.

The act of raising a house involves potentially lethal amounts of force and weight that can react in unpredictable ways. Relying on a jack to support the structure while working in danger zones is extremely risky. There should always be some fixed means of support, such as cribbing in place to support the structure, should the jack fail. Alaska home owners are renowned for their “do it yourself” attitude.

However, sometimes house leveling should be left to a professional.

Q: I have some foam board insulation I want to put on the outside of my house. Is it a problem that it’s wet?

Be cautious with wet foam board insulation. The more water in the foam, the less insulating value it has. If you have a piece of foam that is so saturated it weighs a lot more than a dry piece, it will not have the same insulative value as the new, dry piece of foam.

Also, since the water got in, there is a good chance it will get out.

If you have a wall that is susceptible to moisture damage, it is not a good idea to put wet foam on your structure.

What's Old Is New Again: Traditional Knowledge Inventory Informs Innovation

From treehugger.com:

Low-tech Magazine, consistently highlighting how age-old low-tech solutions are thoroughly applicable in creating a more eco-friendly world, serves as a useful antidote to the usual high-tech hubris that infects much of the new green deal talk. A recent post on the newly established Traditional Knowledge Inventory is no exception.

Though not fully fleshed out yet, all of the topics are fascinating for lovers of human culture, and many offer great practical promise today and for the future. Here are just three examples that caught my eye; there are plenty more at the link above which are worth perusing for a while.

Continue reading: What’s Old Is New Again: Traditional Knowledge Inventory Informs Innovation