Attic temperatures in coastal South Carolina without proper insulation can commonly reach temperatures of 130 degrees or more in the spring through fall months and generally mimic outside temperatures during the winter months. In our region there are two common insulation methods used to complete the “top” of the thermal envelope of a home.
Spray Polyurethane Foam Insulation on the underside of the roof deck is considered the most effective application because of its proficient sealing technology and superior insulation values. By spraying foam directly to the underside of the roof deck no air or moisture will infiltrate your attic. Spray foam on gable wall ends and attic rims add more support for you ceilings and additional thermal barriers. Every penetration is completely sealed so there is no air infiltration between the outside environment and your attic space. Homes with HVAC ducts and mechanical equipment in the attic space will see a tremendous increase in efficiency by now having this equipment within the thermal envelope. It should be noted that retrofit projects will require the removal of existing fiberglass insulation in the floor. This accomplishes two things: 1) It reduces the risk of moisture by not creating temperature differential between the attic and living space. 2) It allows for the movement of air between the living space and the attic through small penetrations in lighting fixtures, etc.
Both of these work together to create a semi-conditioned space in your attic and help HVAC equipment run more efficiently. With the right amount of spray foam insulation in your roof deck your attic should stay within a few degrees temperature and a few percentage points of the relative humidity of the living space of your home. We like to say, “It’s like having your duct work in your living room”.
Tired of dripping wet ducts in your attic? Tired of moldy registers messing up your ceilings? Give us a call at Carolina Foam Pros and let us help you find a solution to your problem.
Traditional Fiberglass Insulation: Insulated Attic Floor With a Vented Attic
In a vented attic air comes in from from the soffit and/or gable end vents and rises out through ridge vents. This is supposed to move enough air to keep the attic dry and free of moisture related problems. Fiberglass batt, or blown fiberglass insulation, is applied to a home’s attic floor to insulate the living space from the outdoor seasonal weather. Temperatures in vented attics can reach 130 oF or more in the spring through fall months and generally mimic outside temperatures during the winter months. Relative humidities of 80% and greater during much of the year further exacerbate moisture related problems, especially if HVAC ducts and equipment are located in these extreme environmental conditions. This further adds to the stress of your heating and cooling equipment, increases the cost of heating and cooling your home and can result in sweating ducts with mold and mildew around the registers. Furthermore, fiberglass insulation begins losing its effectiveness the minute it is laid down. Gravity is constantly compacting it until it is virtually ineffective at insulating your home.
Crawl spaces are a burdensome responsibility for most homeowners. Crawl spaces with fiberglass insulation are not properly sealed and thus lack contamination barriers and the temperature protection necessary for the longevity of your home. As a result, your living space can be filled with harmful allergens, contaminants, and critters. Closed cell foam insulation sprayed to the floor deck between the floor joists is the most effective way to seal your home from the outside environment and complete the thermal envelope. Closed cell spray foam prevents vapor and air flow between the ground and subfloor, eliminating moisture in the subfloor and preventing cupping floors and other moisture related issues. If you have heating and air ducts or equipment in a vented foundation under your home we highly recommend looking at our crawl space page.
Properly air sealing and insulating walls are imperative in creating today’s most energy efficient homes. Traditional fiberglass applications do very little to seal your home from the outside environment. Spray foam insulation fills every crack in the exterior of your home and seals it tight against the outside environment, as well as unwanted insects and critters. Furthermore, spray foam insulation stays put and doesn’t slide down the walls as the years go on like fiberglass insulation. If you’re thinking about building a new home, or renovating an existing home, please give us a call for a free estimate on the best insulation that money can buy.
In basic terms the Building Envelope, or Thermal Envelope, is the insulation and moisture barrier that separates your home from the outside environment.The integrity of a buildings thermal envelope is extremely dependent on the insulation that is used during construction. A thermal envelope is in place to protect your home from environmental factors such as temperature, moisture levels and the movement air into and out of your home and is an important factor that affects the lifespan of the building.
Crawl spaces and attics are the most important spaces encompassed within your buildings thermal envelope. Both of these areas need special attention due to extreme environmental conditions that increase the chance for occurance of moisture in these spaces. Heating and air equipment is put under tremendous stress in these environments, and can even further exacerbate the moisture problem.
Traditionally, homes in the southeast have been insulated with fiberglass insulation, either batts or the “blow-in” variety in conjunction with vented crawl spaces and attics. Crawlspaces are equipped with foundation vents and attics generally have soffit vents, gable end vents and ridge vents to increase airflow. Unfortunately this practice is entirely inadequate to handle the environmental conditions in our subtropical climate. Insulation materials such as fiberglass and cellulose are not as effective as spray foam insulation and allow hot or cold humid air to enter these spaces in your home depending on the season. Utilizing spray polyurethane foam insulation you can improve your home’s energy usage, structural integrity and indoor air quality.
When creating sealed spaces in attics and crawl spaces there are two important things to be considered: 1) The space should be completely sealed from outside environmental conditions. Extreme temperatures and high relative humidities in coastal South Carolina make it virtually impossible to control humid air infiltration in a ventilated attic or crawlspace. 2) The space should be semi-conditioned. In attics, air movement between the living space and the attic, combined with duct leakage, will generally keep the temperature and relative humidity of the attic within a few degrees and RH% of your living space. Sealed crawl spaces are generally conditioned with a dehumidifier. Small HVAC supply lines may also be added to these spaces if additional control is desired.
Types of Spray Foam
Closed- Cell vs Open-Cell Foam Types
We spray both open and closed cell varieties of polyurethane foam. Both types of foam are far superior to traditional fiberglass applications. However, there are important distinguishing characteristics that should be considered and each can be catered to specific applications. Open cell foam is approximately .05 lbs/ft3 and is “light and soft” to the touch. Closed cell foam is approximately 2.0 lbs/ft3 and “heavier and rigid” to the touch and can add as much as 30% additional structural rigidity to a home. In general, open cell foam is used in roof decks and walls. Closed cell foam is primarily used on subfloors, but may also be used in walls and roofs where additional structural rigidity is desired, or where space is limited. Both types of foam are designed with specific characteristics to provide different functions for insulating your building. We at Carolina Foam Pros will provide you with all of the technical information you need to help you decide which foam best suits your particular application and budget.