Benefits of Spray Foam

  • Has high R-value per inch (open-cell 3.5 per inch and closed-cell 6.0 per inch)
  • Eliminates air infiltration
  • Helps control moisture and condensation
  • Reduces convective currents in walls and attics
  • Eliminates wind washing
  • Effective at low and high temperatures
  • Provides the correct environment so that the ventilation system performs more efficiently
  • Closed cell SPF adds structural strength and glues a building together, thereby making it more resistant to racking events, such as hurricanes and high winds.
  • SPF reduces noise from outside by air sealing the building.
  • Closed-cell SPF can provide an added barrier against water intrusion.
  • SPF reduces drafts and increases comfort.
  • SPF helps maintain a comfortable, constant, temperature throughout the building, from room to room and floor to floor.
  • SPF assists in improving indoor air quality.
  • SPF reduces the infiltration of outside air pollutants and soil gases.
  • SPF can reduce moisture condensation and mold growth within the building walls and roof.
  • Excellent insulation efficiency of SPF can reduce heating and cooling usage dramatically.
  • HVAC equipment can be down-sized, thereby reducing construction costs.
  • SPF will not sag or settle.
  • SPF can eliminate the need for separate housewrap and vapor retarders.
  • SPF helps conserve energy, reducing CO2 emissions.
  • SPF contributes LEED credits for sustainable, green construction.
  • SPF can help reduce structural damage caused by high winds.
  • SPF contains no formaldehyde or ozone depleting substances.

Open Cell / Closed Cell Foam

There are many types of insulation products available. Two of the very best available are spray applied polyurethane foam also known as SPF. Typically these are categorized in either their Open Cell or Closed Cell formulation which is determined by its density. Generally any foam with density of 1.5 lb/cu/ft or greater would be considered a closed cell formulation. Anything less would be an open cell formulation.

Both of these materials have incredible insulating properties. SEE MODERN MARVELS VIDEO on the right side of this page. We specify the use of both of these materials on a regular basis. One systemic problem we see in the industry is that many insulation contractors specify one type of foam and try and discredit the use of the others with misleading and/or inaccurate information. Our approach is much different in that we believe that both open cell and closed cell have excellent qualities, but should should be strategically used for maximum performance AND value.


Existing Homes/Envelope Problems

If you own or ever have owned an older home, you probably have lived with comfort and efficiency issues, at least during extremities in the weather. It could be the coldest part of the winter or the hottest part of the summer, but there is a sense that something is wrong. Problems like drafts, cool or warm rooms and floors are quite common in these homes, but are just as common in newer homes and in some cases even more due to unprofessional workmanship. These issues may even keep you from the enjoyment or use of that particular space. If this is the case, you have a building 'envelope' deficiency that should be addressed.

Some homeowners try to solve these issues with a call to their HVAC company. They believe that if a room is cold or hot, that surely the heating and air company can fix it! The HVAC company will gladly come out and give you some relief...and a nice bill in some cases. You can see some benefit from this effort and expense, but unless the underlying problem is addressed, the REAL problem, thenthe problem is not truly solved. Only in solving the deficiency in the insulation will this problem be fixed.

Bonus Rooms

There are typical problem areas in homes of any age. For example, a finished room over a garage can be a significant problem. If you have one then you probably have experienced these problems. Whether it is too hot in summer or cold in the winter, it is definitely caused by a deficiency in the 'thermal envelope' of that room. There is no doubt the current FIBERGLASS insulation in the floor, walls and ceilings is showing us once again why this building material should be dismissed as an ineffective insulation material for use in today's homes. Sure, it's inexpensive upon initial installation and that is why builders used it, but is it the better investment? Is it really cheaper? NOT A CHANCE! We urge all of our insulation clients to consider the fact that "the cheapest insulation, is ACTUALLY the most expensive...and by far!"

Consider the cost of wasted energy, the cost of correcting the problem later. Consider the very durability and cost of the shortened lifecycle of your HVAC system trying to compensate for the insulation by continuous operation. Lastly, consider the cost of your comfort, is that worth anything?

We believe that once the true cost of poor insulation is acknowledged, most home owners will select spray foam insulation as their best investment.

To correct these problems later simply requires a greater investment of time, money and inconvenience than if it were simply done correctly when built.

If a room over the garage is cold in winter, it is the garage ceiling. If it is hot in summer, it is because the radiant heat from roof is super heating the sloped or flat ceilings or areas behind kneewalls. Remember, fiberglass does not stop radiant heat. This is a well documented Building Science Fact.

Most important, these poorly insulated rooms not only affect that room (although here it is more obvious) they actually affect the entire home.

Whether this is a just a spare room, play room or God forbid a master suite or nursery, our team at SprayFoamEtc can make this problem go away in less than a DAY!! We have proven specifications that permanently solve this problem. Many of our client testimonies are written for this reason.

We have been identifying, specifying and repairing these fiberglass insulated homes for over 10 years. For all these years it has been the same complaints:

"My bedroom is too cold in the winter, we can't even walk on the floor in the bathroom."

"My children sleep downstairs because it's too uncomfortable in summer."

"Our home has odors during the rainy season."

"Our second floor is always so cold in winter and warm in summer."

"Our HVAC system runs non-stop"

When asked how long this has gone on, many admit it has went on for years. They simply assumed it was normal for their home and learned to live with it.

Comfort, efficiency, and safety issues should not be ignored. They should be corrected.

Should You Add Insulation or Install New HVAC System?

Should you spend your money on a better building envelope (air barrier and insulation) or on high efficiency air conditioners, heat pumps, or furnaces?

It's all stuff to help cut down your energy bills, right? True, but there's definitely a preferred order (when you have the option). Ironically, the more efficient the shell, the harder it is justify expensive high-end HVAC systems.

Here's the way to look at this.

Think of your house as a basketball game. The HVAC system is your offense. The building envelope is your defense. You might have an amazing offense, but if you keep getting clobbered on defense, you're going to wear yourself out on the offensive side just trying to stay in the game. The better your defense, the less you have to rely on a high-powered offense. And you know what they say: "Offense sells tickets; Defense wins championships."

When talking about the effective use of super insulation material like spray foam, the building envelope reduces the amount of heat flow between inside and outside to such a degree that the house needs little heating and cooling.

So, as odd as it sounds, the more energy efficient the home is, the less sense it makes to put in high efficiency HVAC systems. Do as much as you can with the building envelope before you tackle the HVAC side of the equation. If you start with the heating and cooling equipment, you've probably lost the battle before you've even begun.


Unvented Attic and Cathedral Ceiling Construction

Bill Rose of the University of Illinois states in unpublished report:

"Researchers have compared the shingle temperature of both vented and un-vented roof systems. It has been shown that although ventilation has some effect on the attic air temperature, it has much less effect on shingle temperature. The exterior surface of the shingle is practically unaffected by the presence or absence of ventilation in the attic."

History of Roof Venting

Before the introduction of insulation, moisture was not a problem in roof spaces. Roofs were exposed to warm, humid interior air. This warm air raised the interior temperature of the roof space and decking materials. The roof itself, made of vapor-permeable, natural materials, allowed water vapor to pass through it to the outside without condensing on the interior surface.

With the introduction of insulated roof spaces (attic and cathedral ceilings), the temperature in attics was reduced and water vapor passing through the ceiling to the attic encountered decking materials that were now colder than before. Condensation resulted, causing moisture problems and in winter, a build-up of ice.

The solution was to install a vapor diffusion retarder (VDR) on the warm side of the insulation, and to ventilate attics to remove any water vapor that succeeded in passing through the VDR and the insulation.

Similarly with cathedral ceilings, designers and builders faced similar moisture problems. Their solution was to leave an air space between the roof deck and the insulation material. Vents at the soffits and ridges allowed outside air through the space. The function of the air space in a cathedral ceiling is exactly the same as the function performed by attic vents.

Modern attic and Cathedral Ceiling Technology

Open and Closed Cell Foam provides architects and builders with a new tool. While this modern material may be used with ventilation in the same configuration as glass fiber, it also allows us to roll back the clock and build as our forefathers did. There is no longer a need for ventilation or air spaces. This is accomplished with spray-in-place, air sealing foam insulation either in its open or closed cell density from SprayFoamEtc.

Purpose Of Present Conventional Roof Space Ventilation Practices

Conventional purposes for ventilation and the air spaces in roof spaces are:

  1. Remove moisture
  2. Lower the temperature of the roof to impede the buckling of roof shingles
  3. Prevent temperature rise in the roof deck, which could result in ice damming

Moisture problems and ice damming in roof spaces are caused by air leakage from within the conditioned building and vapor diffusion, which allow moisture to pass through fibrous insulation materials and to condense on the nearest cold surface. It is well documented that, in most situations, diffusion accounts for only 1% of moisture transfer, while movement of air accounts for 99% of the total moisture load on roof spaces and materials. Thus, controlling air leakage virtually eliminates moisture problems.

Scientific research (University of Illinois Small Homes Council, and Florida Solar Energy Center) has determined that the maximum exterior roof temperature for roofs without ventilation or air spaces is virtually the same as those with ventilation and air spaces. The tests, conducted over six months, found that, in the critical high-temperature range above 140† F (60† C), there was only a 3† to 5† F (1.6† to 2.8† C) difference in the non-vented roof. They concluded that any effect of the ventilation was far out-weighed by the solar gain- so that no difference could be expected to occur to shingles, with or without ventilation.

In Montana, a mountain state with heavy snowfall, insulating cathedral ceilings with spray foam without ventilation or air space has been standard practice for many years. There is no evidence of an ice-dam problem in those homes. Similarly foam-core, stress-skin panels (SIP panels), without ventilation, have been used as roofing for decades, with no evidence of problems.

Unvented roofs are now widely accepted in humid climates like NC, SC, Georgia and Florida.

Why Spray Foam Does Not Require Ventilation: Air Leakage Control

Spray foam has a low air permeance – low enough to be classed as an air barrier. Therefore moisture movement through foam by air transfer is virtually nil.

Why Spray Foam Does Not Require Ventilation? Vapor Diffusion Permeance

The 1% of moisture that is conveyed by diffusion is usually not a problem, because the amount is so small that it is measured in nanograms (one billionth of a gram). Its effect is easily overcome by normal drying cycles inherent in wood materials.

Five inches (25 mm) of open cell spray foam has a vapor permeance of 10 perms (565 ng/m2/s). This property allows low rates of moisture diffusion to occur, just enough to allow breathing of adjacent framing and decking materials to prevent moisture entrapment. The minimal diffusion that does occur through foam will pass through the material without condensing, provided that the substrate to which it is attached is equally (or more) vapor permeable.


If your home was built prior to 1970 and not renovated, there is a strong possibility that there is no insulation in exterior walls. That's right, up until this time period, exterior wall insulation was not even standard practice! Even if your walls have been insulated, chances are the current fiberglass batts are completely ineffective in terms of making significant difference in the performance of the home. The older your home is, the more ineffective the fiberglass has become. Advances in fiberglass insulation and the recommended Rvalue has increased, but it still remains a poor insulation material which is widely used to this day.

We utilize a thermal imaging camera for existing exterior walls as well as an in-depth inspection of other areas of the home to determine the need for exterior wall insulation.

We can then proceed with our pour-in-place (PIP) foam formulations to drill and fill these cavities with a medium density foam. Exterior wall insulation whether by itself, or as part broader scale insulation remediation, can have an incredible impact of the home's performance.

Final Word

Open and closed cell foam has been applied in unvented roof spaces in all climatic extremes for well over 20 years. There has not been a single reported complaint about any lack of performance or failure with the material. However, the building code in your community may dictate that ventilation and air spaces are still required. The final authority may not be the building code, but a professional consultant. Many jurisdictions allow for alternative installation techniques provided they have been reviewed and approved by professional architects or engineers. Finally, many building codes have been amended in recent years to allow for unvented roof installations. This is a promising sign that this approach to insulating attics and cathedral ceilings may be universally adopted in the future.