By CCHRC Staff

Q: A lot of older homes use pink or yellow fiberglass insulation around doors or windows. If I’m going to reseal any of them, is there a better way to do it?

Fiberglass is a great insulator but still allows air to flow in and out. A can of minimal expanding spray foam will more effectively air seal your doors and windows.

Open the trim around the windows then push the fiberglass in slightly. Make sure the spray foam fills all the cracks for a tight seal. The goal is to make the area around doors and windows as airtight as possible.

Even low expanding foam will swell significantly. Painter’s masking tape can be used to protect finished surfaces from spillage and can be removed once the foam cures. As an alternative, a compressible foam backer rod and silicone caulking can also provide a good long-term seal in difficult spots — especially when if you are working in temperatures too cold to apply foam. Also moisture can affect the foam and it should not be applied to wet surfaces.

Q: When it comes to heat and energy expenses, why are walls such a big deal?

In looking at a home, people often think their roof is where they lose the most heat.

The walls, however, might be a bigger issue.

On a home, walls compose the greatest surface area exposed to the outside. This is important because the laws of thermodynamics teach us that heat will always move to cold whether it moves up, down or sideways. With an exterior wall, one side is always exposed to the cold so heat will naturally always try to move inside to outside through the wall. We tend to assume heat always rises, so our roof must be responsible for the greatest heat loss. What actually happens is that air rises when it is warmed and it becomes a vehicle for the transfer of heat. This does not mean there is any reduction in the amount of heat moving through walls. A home can easily have many times more heat loss through walls than through the roof.

There are many ways to reduce heat loss through walls. The simplest is to carefully caulk and air-seal any places where air can move from the interior or exterior, particularly around windows and doors. Re-insulating walls and adding additional insulation inside or outside can be done if proper techniques are incorporated.

Be sure to consult with or hire a professional before attempting this kind of weatherization.

Remember, a house is a system and what is done to one part of a house may affect overall performance of the home both positively and negatively.

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.

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.

By CCHRC Staff

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

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.

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.

By CCHRC Staff

Q: How can I get rid of carpenter ants without using toxic chemicals?

Carpenter ants are tenacious creatures and once they start a nest, they can be difficult to eradicate.

Prevention is always the easiest solution.

If you can keep them from establishing a foothold, you will be better able to protect home and property. Remove any wood scraps and tree stumps from around your home.

Sheets of plywood, old tarps, pallets and anything else that provides ground cover, particularly if it is moist, can provide a staging area that will bring ants that much closer to your home.

Once they gain entry to the house at ground level, ants will often start a nest in an area that is damp or prone to decay. Many times the infestation starts at the foundation. Crawlspaces and basements, and any spots that may be prone to moisture damage, will be especially attractive. Rim joists, areas where decks are attached and areas around improperly flashed windows present places that allow the ants to get started.

The ants do not eat wood, but tunnel into it to make their nests. As a result, rigid foam board, which is often used around foundations, also presents an appealing target.

Even though ants prefer moist areas, they are not limited to that environment and will expand their nest building into walls, floors and even work their way into roofs.

A mature carpenter ant colony will have a main nest and satellite nests, which the ants use to broaden their foraging grounds. If the ants can be traced back to the main nest in the woods, then a localized dose of ant poison can be very effective.

Chemical poisons may work well, however they are the least desirable from both a health and an environmental perspective, especially if there is a chance that pets or children could come into contact with them. Many ant poisons are extremely toxic and if you are considering buying a product, research the long term effects and handling precautions online.

Some insect poisons may break down slowly and can be absorbed into the food chain by nearby plants and animals or dispersed by rains and groundwater. So if the main nest cannot be located and safely isolated, sprinkling poisons liberally around the grounds in the hopes it will kill the ants should be avoided. Generally, chemical ant control should be left to a professional who will be able to determine which product is best suited to a particular application.

A lot of the ant baits sold in the stores are designed for Lower 48 species of ants, and the primary attractant is sweets.

Carpenter ants are foragers that eat proteins (such as insects), so sweets will not appeal to them in the same way.

Occasionally, a carpenter- ant-specific bait will make its way on the shelves, and these can be effective. If you buy an ant bait station and leave it exposed, it may attract pets, squirrels, voles and other animals.

Before you begin an ant control strategy, check with a local exterminator. Some exterminators may have access to effective carpenter ant baits and contact poisons which are not available in stores.

When it comes to nontoxic products, diatomaceous earth is available at many feed and garden stores. It acts as a physical killer rather than a chemical killer by working its way into the ants’ breathing tubes and joints. When the ants clean each other, they can also transfer it among themselves. Again, it will do little good putting it on individual ants, you must find a nest.

The presence of ants can create problems in every part of your home, and repairing the damage can be expensive, so the sooner you eliminate ants, the better.

More information on combating carpenter ants is available at the University of Alaska Fairbanks Cooperative Extension Service at www.uaf.edu/ces/.

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.

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 have a concrete foundation. I heard insulating your foundation can save heat. How can I do that?

Concrete is very conductive, and heat always goes to cold, so a foundation without insulation is basically a bottomless heat sink. If the foundation is un-insulated, there are definitely opportunities to save some heat.

Current code requires an R-value of 15, which is about 3 inches of blue foam.

Ideally, digging out the outside of the foundation and insulating the outside will keep the foundation warmer but doing this type of work on the outside of a home is not always practical. In such a situation, put foam on the interior of the home’s outside walls and tape the joints.

On a similar point, the rim joist area is prone to air leakage where the joists meet the outside wall.

Often, fiberglass insulation is put into joist bays, but that is not enough to stop air leakage. A better choice is to install sheets of foam fitted to each joist bay, then spray foam around the edges.

Another option is to hire a spray foam contractor to spray between the joists.

These techniques will help stop air flow and heat loss through that part of the foundation.

Q: Is there a way to limit the amount of offgassing in my home or ventilate it in some way?

For those who do not know the term, offgassing, or outgassing, is the release of gas from materials over time. Often these materials are plastics or other petroleum-based substances that release chemicals that can be hazardous to health.

For starters, try to use “green” materials that do not offgas hazardous substances like formaldehyde and other volatile organic compounds (VOCs). Low VOC and non-VOC paints, carpets, caulks and glues are available. Furniture and fabrics also offgas, so look for healthy alternatives such as solid wood furniture and other non­VOC products. In new construction, despite the best attempts to use entirely healthy products, there will probably be some type of VOC. Before moving in to a new home, ventilate the home as much as possible. One method is to turn the thermostat up very high, to promote outgassing, and run the ventilation system at high speed for a day or two. This tactic will help “bake out” and vent VOCs.

In older homes, particleboard countertops, shelving and cabinets can be coated with a non-VOC sealant to prevent further outgassing.

Also, use greener cleaning products and store chemicals outside rather than indoors. Try to purchase only as much as needed so unused chemicals do not sit around.

The best way to get rid of offgassed substances is to regularly make sure the home is properly ventilated by opening windows and using mechanical ventilation.

A well-ventilated home will exchange air more frequently, exhaust pollutants and bring in fresh air.

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.