NEW HOME CODE COMPLIANCE
When properly installed in new construction or open-walled major renovations, spray polyurethane foam insulation outperforms any other traditional insulation product on the market by not only insulating, but also greatly reducing airflow and the transfer of water vapor. Working alongside a spray foam insulation company owned and operated by experienced RESNET and BPI Building Science professionals with applicators who are manufacturer-certified is one of the most significant contributing factors in ensuring that the proper application will be proposed and the air envelope will be tight, not just to the eye but under home depressurization testing.
However, if an inexperienced spray foam company, or a company that does not make it their standard practice to ensure great detail, poorly installs spray foam or incorrectly chooses a material that is not suited for a particular application then the air and vapor barrier may be greatly compromised. Also, if the HVAC contractor is ignorant to air-conditioning Best Installation Practices, current building code, and proper fresh air and combustion air requirements then the house may suffer from moisture and indoor air quality problems resulting in mold and mildew growth while leading to “sick house syndrome” and potential litigation.
All Details Of Construction Must Be Known Up Front When Planning For Spray Foam!
All details of construction must be known up front when planning for spray foam. Consider how to handle the following products and materials:
- Reflective sheathing such as Techshield
- Radiant barrier
- Mechanical or passive turbines
- Open combustion furnaces & gas water heaters.
- And more …
Decisions are required up-front early in the process to ensure a properly balanced, energy efficient home.
Make sure a Manual ‘J’ Version 8 [Elite and Wrightsoft Right-J are currently ACCA Certified] is performed on the structure. Plan your equipment selection to match the structure load for both latent [humidity] and sensible [temperature] heat. Number One priority of the air conditioner in our Climate Zone 2 is to DEHUMIDIFY. If the prospective HVAC [Heating, Ventilation, Air Conditioning] contractor can not say with absolute certainty that de-humidification is the first and foremost priority of your home in our climate zone then drop like a hot potato!
Recommended air handlers are closed combustion 90%+ Furnaces and Heat Pumps instead of 80% Furnaces. If 80 AFUE furnace is used then the installation must abide by 2009 International Fuel Gas Code National Fire Protection Association NFPA 54 to determine combustion air opening size.
Determine your mechanical [ERV], or passive fresh air requirements according to ASHRAE 62.2 2004.
It is recommended to have a dehumidifier, or a properly sized two-speed condensing unit with a variable speed blower which will perform well when properly sized. Special note must be made concerning two-speed/variable-speed air-conditioning units. This is not an additional cost attributable to spray-foaming a home. However, it is a system which is designed to adjust accordingly to the fluctuating sensible and latent heat loads commonly experienced with our particular climate zone. These types of systems are designed and manufactured specifically for our hot/humid climate. Some HVAC contractors commonly argue that spray-foaming a home requires the purchase of this type of unit. The fact is that any home in our climate zone which is built to tight standards will benefit greatly from these types of units. Whether it is a spray-foamed home or a home using more traditional insulating methods the fact remains that the same practices and codes apply which dictates the use of a Manula J program and adherence to ASHRAE 62.2 2004 standards.
Determine what special situations you may encounter such as exhaust systems, large sources of humidity [Spa’s and whirlpool bath’s] and special needs inherent is the building. Again, many of these features may need to be accounted for in a Manual J heat load calculation.
Remember the Air Barrier of the envelope. Consider how to handle caulking of all stacked studs & plates, windows, doors, corners, around penetrations, etc. Drill and fill all T’s, corners, headers, etc. This should be standard practice and SHOULD NOT be offered as an additional service as many spray foam companies do in order to make a foam bid look cheaper than it really should be.
After installment of foam run a blower door test to calculate the leakage rate to determine if corrections are required and a preliminary ACH [Air Changes Per Hour] for ASHRAE 62.2 2004 standards.
The spray foam sales person, foam installer and HVAC contractor must be in constant contact with each other before and after the installation of foam.
An Additional Note
Your existing structure, as it currently exists, may require a much better understanding of Building Science than new construction. A “gut job” or extensive renovation can introduce many scenarios that will require a different handling then walking into a fully framed and sheathed home ready for spray foam. In many cases – especially concerning the typical old New Orleans housing stock – there will be weak spots or hard-to-reach areas, or areas that may suffer from a high vapor drive that need to be addressed. Also, along with energy efficiency measures and proper vapor control, structural integrity may be a feature that is sought after which may demand spraying different materials or thicknesses in a specific order or “prepping” the structure before installation. Homes such as these demand a thorough investigation early in the process by an experienced building science professional and licensed spray foam contractor.