ASK FOR LICENSE AND INSURANCE PRIOR TO THE START OF ANY FOAM INSTALLATION. WE ALL PAY FOR A REASON! WARRANTY AND SECURITY
As a licensed Louisiana State residential and commercial contractor, I get questioned alot in regards to the proper application of the different types of foam on the market. One question that comes up alot is the proper way to insulate an attic. Let me first start by stating for the record that I am an absolute 100% fan of a “Vented Attic System”. My reasons are many, but before I go into the reasons why, let me first start by saying that houses need to breathe! So many problems can arise from closing off an attic completely that unless you are going to hire a licensed professional holding a Louisiana State Certified License and are registered with the Secretary of State and carry all proper insurances, you shouldn’t allow anyone foam applicator to tell you to “close off your attic”! I say this with the utmost passion since as a registered home expert, I see and hear many different reasons. So without hesitation, I will tell you the proper methods for Vented vs. Unvented attic systems with spray foam insulation.

UNVENTED ATTIC SYSTEM:

First, if you have gas appliances in your attic, you run the risk of Carbon Monoxide poisoning if not properly installed. Total electric homes obviously do not run this risk but do run the risk of “moisture saturation” which can lead to dry rotting of the homes’ wood structure, let alone mold and mildew issues. So, proper installation criteria most first be determined:

1. Gas and Flue test most be performed to insure that all expended gases can properly escape. In the winter of 2009, a family was diagnosed with Carbon Monoxide poisoning and as an expert witness to the case, the family has suffered physical consequences and the installer is “out of business” Being uninsured, his contracting days are over…, or are they. Ask for license and Insurance prior to the start of any job!
2. Air-conditioning sealant test should be performed to ensure that the a/c ducts are not leaking more than 5-7% from the vent boxes, air plentum and coil box. Air coming from the fan unit at the coil can be as cold as 42 degrees and unfortunately when mixed with the hot and stale air of an attic in the summertime at 140 degrees average, will cause moisture at such a rapid pace, your sheet rock is history! We all know what a glass of ice water does outside in the summertime… It sweats. Your attic will be no different. I have seen an entire attic fill with well over 1” of water in less than 48 hours causing the entire ceiling sheetrock to be removed. Once again, the foam applicator was not licensed and the homeowner suffered the financial consequences.
3. To seal the attic completely, each gas appliance has a standard CFM stated in the specs that will determine air-flows. To be safe, I recommend using a 6” hard pipe properly fastened to the floor joists or to the rafter that will run from the eaves of the house to within 4” of the face of the furnace grill or to within 12” of the water heater. It is essential that it be properly installed and I recommend that a licensed Louisiana Mechanical Contractor do the work. Also, a licensed contractor will understand the proper air intake requirements. Should it be bent or knocked loose while moving things around, negative pressures could build in the attic causing what is referred to as “back drafting”. Meaning that when the furnace and water heater are operating, they begin to use the air in the attic at such a rate, that the exhaust from the expended fuel is unable to escape filling your attic with poisonous gases and possibly circulating them throughout your home. I have even gone the extra mile in adding and additional intake to the attic to ensure that there is always a release for fluid air-flows. However, as I stated in the beginning, I am a fan of the “vented attic system”.
4. Now when sealing the attic, it is paramount to use the proper spray foam which in 95% of residential cases will “open cell foam or 0.5lb (half pound) foam. Pay particular attention to the furnace flues at the roof line as these have to be surrounded by a fire foam or fire caulk. Do Not Allow regular open cell foam to applied to these areas as there is a potential fire risk.
5. Contract only with a State Licensed and Insured Foam Applicating Company. ASK FOR INSURANCE WITH “YOU AND YOUR HOME” LISTED AS INSURED!

VENTED ATTIC SYSTEM:

1. Check for gas appliances in attic, if none…. Good.
2. Check for duct leaks, not as important as in an unvented system as far as the moisture saturation problem because it can not happen with air flow, but heck, your there and might as well make sure the ductwork is as tight as can be to achieve the maximum efficiency. This is something that you can do yourself by strapping and painting on a ductwork mastik that can be purchased from HomeDepot or Lowes. Or call a licensed professional. Costs of this is usually around $15 per seam plus the service call. Your cost will be under $50 plus your time and possibly a back ache when your finished.
3. I find that closing off approximately 85-90% of the attic eaves and leaving only 1-2 turbines or vent fans on the roof deck open is just right. This is the way I have done my attic and over 500 more and during the summer months, it is normally 5-7 degrees warmer than the air in my house. Big benefit is that during the winter months, air has far less chance of escaping rapidly and if it does, at least you can rest assured that the expended poisonous gases go out with it.

For questions about proper depths of foam on roof lines, feel free to contact me. I am always available to helping homeowners achieve greater home efficiency.

Brad Harris (504) 383-3261