Frequently Asked Questions

What does RVALUE mean?

RVALUE is a materials ability to resist the transfer of heat through itself. Insulation products commonly provide their RVALUES on a per inch basis. Each insulating material possess their own RVALUE per inch based on their performance during testing. The more inches that have been installed, the higher the accumulative RVALUE the material achieves. 

How much RVALUE should my attic insulation have?

In the San Antonio area, the IRC requires a prescriptive minimum RVALUE of 38 in an attic when using loose blown fiberglass or cellulose. The depth of your loose blown insulation should measure up to 12-14 inches, depending on the materials used. Due to a higher performance from SPF, a spray foam attic containing 5-6 inches of open cell foam with RVALUES of 19 to 22 will perform extremely well.

What is poly sealing?

Poly sealing is what we do to seal up small gaps and cracks at framing penetrations and fire stops. Areas where we poly seal include but are not limited to door and window frames, bottom and top plates, and framing gaps. Sealing these gaps contribute to higher energy performance and fire safety.

How much does insulation cost?

The short answer is that it depends. There are many factors involved when installing spray foam insulation and they all influence the cost. It is important to have an insulation professional inspect the project and address all of the obstacles in order to perform a high quality installation.

Can a house be sealed up too much?

This questions is almost always tied to spray foam insulation. The answer is no. If the entire building system is configured properly, using spray foam insulation will achieve a high level of energy performance, as well as help to INCREASE indoor air quality. The HVAC system, when calculated to work in hand with spray foam insulation, monitors the home's air quality. When needed, the HVAC system pulls in outside air which is filtered and conditioned before being moved into your home.   

Why is spray foam insulation installed at the roofline?

San Antonio resides in a hot-humid climate zone, resulting in a very hot sun shining on our rooftops for a long time each day. This leaves an unconditioned attic to the mercy of extremely high temperatures and wide swings of humidity. In Texas, creating an unvented and conditioned attic through the use of spray foam provide great benefits toward efficiency and comfort.

Should I remove the old insulation before adding spray foam?

We recommend removing any existing insulation before spray foam insulation is installed, and for a number of reasons. Chances are your old insulation has been around for a long time, and has collected a large amount of dust, dead bugs, and remnants left behind by rodents. The original insulation can be nuisance in itself. It creates a large amount of dust when disturbed which is unhealthy when inhaled. Old fiberglass is also irritating when coming in contact with skin.


Another reason to remove the old insulation is related to providing proper sealing from the spray foam insulation. In order to create a completely unvented attic, the spray foam insulation must seal the entire lower perimeter of an attic. This lower area adjoins with the soffit and eaves. In most cases, the original insulation is resting in or near this area. If it is not removed, it will block or mix with the spray foam insulation. In turn, it prevents the spray foam insulation from completely sealing the gaps. These gaps will result in continued air leakage. 


Installing SPF in an attic transfers the thermal barrier from the ceiling to the roofline. By doing this, the entire attic now becomes a conditioned space. HVAC systems direct conditioned air into the living areas of a home, but not directly into the attic. If the original insulation remains on the ceiling it greatly reduces the migration of the conditioned air from these areas back into the attic. Removing the old insulation allows the conditioned air to move into the attic, which contributes to balancing temperatures and moisture levels.        

Will spray foam insulation ruin my shingles?

Studies have show a minimal effect on shingles when spray foam insulation is installed in the roofline. To add to this, many homes in the San Antonio area have had spray foam insulation installed with minimal increased degradation to shingle, tile, and metal roofs. 

How long does the insulation last?

Loose blown insulation is more susceptible to declined performance over time. This material is easily manipulated by people, animals, and wind washing. More recent manufacturing processes have produced blown fiberglass products which are resistant to settling. Cellulose, however, will still settle over time. As the insulation compresses, it loses RVALUE. Spray foam insulation will last the lifetime of a building. As long as the building remains in good condition, the physical properties of SPF will see little to no change. This being said, spray foam insulation will degrade if exposed to long term sunlight. This would more likely be the case with exposed SPF in a large open building. A coat of thermal barrier and paint (color to taste) will provide exceptional long term performance.

If you have a question that is not answered on this page, feel free to give us a call. There are a lot of things to consider, and we will be happy to assist you with whatever questions you may have.