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Foam Insulation – The Hidden Super Construction Material

Current conventional insulation, fiberglass and cellulose, are readily available in rolls or blown forms. While, conventional insulation provides some form of resistance to heat transfer, its overall effectiveness needs significant improvement.  Approximately 40 years ago, foam insulation was first introduced into the construction industry. The initial introduction was plagued with problems, off gas of formaldehyde and VOCs, material shrinkage, and sensitivity to off gassing chemical and VOCs. However, through years of improvements in research and development, raw material quality and installation equipment, the development of open cell and closed cell foam have significantly improve thus greatly improving the ability to insulate a home/building.

When addressing heat transfer into and out of a housing/building structure, one needs to address all three forms of heat transfer:

  1. Conduction – conduction is the transfer of heat through a solid member such as studs in your walls and roof, sheathings, etc… The resistance to conductive heat transfer (R-values) is the current standards used for by the industry to measure the effectiveness of the insulation.
  2. Convection – convection is the transfer of heat through a viscous material such as air. Regardless of the R-values, if the insulation material allows air to transfer/move through it, its overall insulation effective performance is significantly diminished. How effectively a structure have been built to resist convective heat transfer can be measured through the use of “blow door testing”
  3. Radiant  – radiant heat transfer is the transfer of heat through energy waves. For example, the roof from a conventionally vented attic absorbs heat energy from the sun and heats up to temperature in excess of 160 degree F. The heat is then transferred through the roof sheathing and studs through conductive heat transfer and then re-radiate inward into the attic. The result is an attic with temperature in excess of 130 degree F or more. While reflective sheathings and reflective foil claims to reduce the heat by 17 to 30%, a foam insulated attic will stop up to 95% of total heat transfer into the attic.

Why is R-value not a true representative example of insulation values?

In a conventionally insulated home, conductive heat transfers only accounts for about 10-20% of the total heat lost and gains. Convective heat lost can accounts for as much as 60% of the total heat lost and heat gains. In addition, radiant heat transfer (heat gains from the sun’s radiant energy) will account for the remaining 20-30%. Furthermore, the R-values of conventional insulations are tested in a laboratory setting and does not take real life conditions into account.  Studies have shown that fiber glass insulation installed where air transfer are allow to circulate through it, will performed only at 30-50% of the claimed insulation values (ie. An R 13 in the exterior walls is only as effective as an R-5 to R-7 in actual performance value.) It is this author’s opinion that the department of Insurance and Department of Energy reconsider the current and obsolete manor for determining the true insulated values of an insulation  by taken into account not just resistance to conductive heat transfer (R-values), but also heat lost and gain through convective and radiant heat transfer. Oak Ridge National Laboratory (ORNL) conducted an experiment (*) to determine the efficiency of a roof assembly insulated with low density, loose-fill fiberglass insulation and discovered that up to 50% of the heat loss occurred as a result of convection; air circulation through the insulation. This result showed that the air-permeable insulation had loss its anticipated thermal performance level by half and that convective heat transfer had a significant negative impact on insulation performance.

Closed Cell (Medium Density) Foam vs Open Cell (Low Density) Foam.

There currently exist two types of foam being use in residential applications: Open cell – Low density foam, and Closed Cell – Medium density foam. There are positive and negative to both products:

Open Cell Positives:

  • High thermal efficiency, performed at 98% of prescriptive R-values
  • Lower cost – approximately 50% the cost of closed cell foam for same prescriptive R-values
  • Same thermal efficiency as closed cell at half the cost
  • Is a registered air barrier at 3.5” for most open cell foam
  • Cured in under 1 minute
  • Has zero off-gas
  • Does not create dust
  • When engineered with the HVAC system: provides for a healthy, energy efficient, low humidity, and comfortable indoor air quality
  • Adds toward building structure strength
  • Is a durable building material – certain manufactures will guarantee the product for the life of the structure
  • Excellent at suppressing audible noise
  • Has low environmental effects

 

Open Cell Negative:

  • Is not a vapor barrier, so in northern climate zones a vapor barrier (6 mil plastic) is required on the inside of the thermal envelope
  • Some open cell foam product will wick water, if this trait is high in a foam product, it could lead to water issues if house is not properly dried in (seek out hydrophobic foam products)
  • Requires significant trimming and has large quantity of waste

 Closed Cell Positive:

  • Higher R-values per inch when compared to conventional insulation and open cell foam.
  • Is a vapor barrier
  • Provide significant strength to building
  • Excellent at suppressing audible noise
  • Is a durable building material – certain manufactures will guarantee the product for the life of the structure
  • Does not create dust
  • Is a vapor and air barrier

Closed Cell Negative:

  • Extensive period of off-gas (up to 2 years)
  • Not recommended for people with sensitivity to chemicals, allergy, or have respiratory issues
  • VOCs
  • In North Carolina, the vapor barrier is placed on the wrong side of the building
  • Closed cell foam underneath roof can result in roof rot is roof leaks occur
  • Experienced company like Healthy Home Insulation, LLC who installed both open and closed cell foam has made it a practice to not utilized closed cell foam in residential application due to the health water damage liabilities.

Conclusion:

As a consumer, we can significant reduce utility cost for heating and cooling our new and existing homes by 50-70%. We can live in a home with superior indoor air quality, is quiet and comfortable. Foam insulation is the most energy efficient insulation product currently available in the market. The use of foam insulation should however, must be incorporated into the house as a system and not use just as a single building product. Correct sizing of the HVAC system(s) by an experience HVAC contractor or building engineer is strongly recommended and will provide for maximum energy efficiency, long-Gevity of the HVAC equipment, proper ventilation and dehumidification of indoor air quality, comfort and a healthy indoor air conditions. Foam insulation is one of the very few building product that can provide an immediate return on investment for new construction and has a ROI in existing retrofit projects in as little as two years.

Written by: Tu N. Nguyen, Healthy Home Insulation LLC.

Why Does Everyone Want an ENERGY STAR Home?

“ENERGY STAR?  I thought that was just for refrigerators!”

As many people now realize, the ENERGY STAR program isn’t just for appliances; it’s also a respected energy efficiency program for new homes and is the basis for most green home programs. Based on building science, the ENERGY STAR new home program has strict guidelines for energy efficiency set by the US Environmental Protection Agency. 

ENERGY STAR qualified homes feature:

  • Properly-installed, advanced insulation
  • High-performance windows
  • High-efficiency and correctly-sized heating and cooling equipment
  • Tightly-sealed ducts and tight construction. 
  • Independent testing and inspections for compliance by a third-party company

Why do these features make such a big difference?

Properly-installed insulation helps keep temperatures even throughout the house, increasing comfort and lowering energy bills.  Building science research has shown that even small deficiencies in insulation installation make a significant difference in insulation performance – and almost all non-ENERGY STAR homes have poorly-installed insulation. Every ENERGY STAR home’s insulation is inspected by an independent rating company and if it is not up to ENERGY STAR’s standards, it has to be fixed.

Advanced, high-performance windows use protective coatings and improved frame assemblies to help keep heat out during the summer and in during the winter.  They also block damaging ultraviolet rays that can discolor carpet and furniture.

High-efficiency and correctly-sized HVAC systems use less energy and help increase comfort in a home.  Correct sizing insures efficient performance and lowers bills.  Especially important in North Carolina, proper sizing helps reduce humidity levels in your home, increasing comfort and decreasing energy bills.

Tightly-sealed ducts make a huge difference in both comfort and indoor air quality while lowering energy bills.  Leaky ducts can introduce pollutants, moisture and mold into a house and if leaky ducts are in your crawl space, that crawl space air is being pulled into your home.  In addition, duct leaks can cause unbalanced pressures that increase air infiltration into your home. In some studies, sealing ducts reduced cooling bills by about 33%.

Tight construction increases comfort and decreases energy bills. A tight house is much less drafty and has better indoor air quality.  Air leakage in the top plane of the house sets up stack effect, pulling in air from the bottom part of the house – many times from the crawl space and/or garage.  This leakage can account for 5% to 40% of the costs to heat and cool buildings, so it’s not a minor thing.

Independent testing and inspections by certified home energy raters make sure the home meets ENERGY STAR standards.  Each home is individually inspected and tested by an independent home energy rating company utilizing scientific equipment and state-of-the-art software.  These inspections include at least one insulation and building component inspection before drywall to make sure all the “under the drywall” items meet ENERGY STAR’s specifications. In addition, each home has final diagnostic testing using a blower door and duct blaster to make sure air infiltration and duct leakage are within ENERGY STAR’s limits.  This insures that the new homeowner will have a comfortable, healthy and efficient home.

Author: Cass Arble – Brightcut Building Solutions, LLC

What Role on the Home Building Team Does the Surveyor Play?

Quality control during the building process protects the client’s investment for the future.

The land surveyor provides several valued services to the new home construction process including boundary surveys, site design, layout, and construction staking. From the top the most important aspect of the surveyor’s role is one of quality control.

An accurate boundary survey discloses any defects of the parcel to be developed such as encroachments, discrepancies in land area, missing boundary corners or undeclared easements. The boundary survey also quantifies the size, shape and dimension of the building envelope as determined by building setbacks, home owner covenants, environmental buffers and
utility easements.  An accurate boundary survey ensures that the buyer’s vision for their new home will work on the chosen parcel.
Well thought out site design serves as an aid to the client and the builder as well. Placement on the lot, drive access, drainage, foundation exposure and floor height above grade are important considerations for the client. The surveyor will provide an initial site layout to the client based on input from the client and the builder. The client and builder typically have comments and suggestions that complete the final layout.
Once the building process is started the surveyor is responsible for the house layout. There is no

margin for error in laying out the footings and foundation for the new home within the building envelope and as per the client’s vision and architectural plans. A layout certified by the surveyor ensures that the home is positioned on the lot correctly and will not encroach into any setbacks,

across lot lines, or be constructed across any easements and will meet all required covenants and community architectural guidelines.
The final as-built survey of the completed construction by the surveyor certifies to the client, the lender and the community architectural review board that the project has been completed as intended and that there are no boundary issues or site issues.
Your home is an investment in the future. A solid team including the builder, realtor, surveyor, architect, and structural engineer ensures that the client receives the best possible service during and after the building process.
By Charles Eliason, PLS – 3599 Owner Infinite Land Design, P.C., Surveyors and Mappers

Why is Structural Engineering Needed?

Structural Engineering – What are the Benefits? 

According to most local code jurisdictions in North Carolina, you do not need a structural engineer to construct a new home.  You also don’t need to see a physician at any time in your life until the pain warrants immediate care! 

Today’s house plans and building materials simply warrant the review of a structural engineer.  As we strive for energy efficiency, economy, and creative design, we stretch material capabilities and try to balance our champagne tastes vs. our beer budget.  A good structural engineer can ensure that the plan you have chosen will not only meet state building code requirements, but will also be the right mix of building materials to create the home you are comfortable in and willing to pay for. 

The homes that our grandparents bought were typically rectangular in shape and were constructed of standard saw mill lumber and brick and block masonry.  Rooms were typically small (12’ or less in any one dimension) and tall ceiling heights were generally unheard of.  The size and number of windows was small. 

Contrast that to the standard custom homes of today!  We like larger, more open rooms with high ceilings.  We call for energy efficiency and environmentally-friendly construction materials.  We want more glass in a wall than we want insulation and wood framing. 

These construction parameters call out for a structural engineer.  Roofs are no longer simple.  We like hips and gables and dormers and changes in roof pitch.  The structural engineer has the capabilities to define how what looks pretty will be constructed.  From the concrete footings supporting the foundation walls to tracing the load points from roof framing and end reactions of beams, the structural design layout ensures the stability of the structure and economizes the materials. 

If you want your next home to be the baseline model, don’t hire a structural engineer and have it built to code minimums.  If you want your home to be a precision, high performance structure constructed within your budget, hire a structural engineer and find the peace of mind that comes with guaranteed stability and better resale value.

by Brooke Carpenter, Owner – Residential Engineering Services, PA