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Frequently Asked Questions

You have questions, we have answers.

In new construction, at what point in the building process do you install spray foam insulation?
You install spray foam at the same time as the traditional fiberglass insulation, after passing mechanical and framing inspections, yet before hanging sheetrock.
Where can spray foam insulation be used?

Spray Foam insulation can be used anywhere in the home, the same as traditional insulation. Spray Foam insulation is ideal for hard to insulate areas because it spreads to fully insulate the area. These hard to insulate areas can include, but are not limited to:


  • Attics
  • Cathedral Ceilings
  • Basements
  • Walls
  • Crawl Spaces
  • Rim Joists
What is the difference between open-cell foam and closed-cell foam?
Both open-cell and closed-cell foam are great insulators. Both provide an excellent thermal barrier and air barrier. How they differ is that closed-cell foam is waterproof and will not let water move through it. Open-cell foam will allow water to move through it and dry. Insulation should not stop water. Roof, wall and crawl space assemblies are designed to keep water out. If water somehow does get into those assemblies, it needs to be able to dry out, especially in wood structures.
Is spray foam safe to use in my home?
The spray foam we use in your home is essentially made of the same material as the foam cup you grab at the local gas station. It is a cellular plastic where water is used as the blowing agent, and is non-toxic.
What are the differences between STI insulation and loose-fill insulation?
STI insulation foam seals penetrations; hot or cold air can blow right through loose-fill insulation
STI insulation foam does not sag, settle or shrink over time; the settling of loose-fill insulation reduces coverage area.

STI insulation foam reduces condensation within the walls; loose-fill insulation allows moisture to travel freely and increases the likely hood of mold, mildew and wood rot.
STI insulation foam does not provide nesting material or food for rodents and insects; loose-fill insulation is more hospitable to pests.

What are the biggest advantages of South Texas Insulation (STI) insulation system?
  • Low Energy Costs – Utility bills are typically 20-50% lower in homes.
  • A Healthy Home – Less air infiltration means less mold, pollen, and dust travel into your home.
Can I get an estimate on how much it will cost?

Yes! Call 1-210.599.8681 or contact us online!

How long will it take for the job to be completed?
Average project (residential 2400 sq.) would take an average 2-4 days.
How is Spray Polyurethane Foam applied?
Two-component, high pressure systems (typically 100-1200 psi) use 55-gallon drums and are more often used when insulating larger areas on new construction or major renovations on walls and roofs. These products are intended for professional use. These products require special training and the use of specialized personal protective equipment (PPE), including respirators.

South Texas Insulation is equipped with a spray rig (truck) which houses the SPF ingredients, air supply and other items is parked near the home or building to be sprayed. Hoses (up to about 300 ft. in length) are carried to the application area and installers wearing proper protective equipment spray the foam.

What are the different types of Spray Polyurethane Foam (SPF) Insulation?
Open cell is usually found in densities ranging from 0.4 to 1.2 lbs/ft3. One of the advantages that these lower densities provide is a more economical yield, since foam density is directly related to yield (lower density = higher yield).  Gaco Western Gaco Green 052 open cell wall foam has an R Value of 4.21 per inch.


Closed cell polyurethane high density foam is the highest quality spray foam on the market.  In fact, closed cell foam is the only foam that truly creates an air and moisture barrier.  Gaco Western 183 closed cell foam has an R value of 6.8 per inch and has passed the AC-377 appendix X ignition barrier test.

Does the foam change physically over time?
No, it’s physical and insulation properties are constant.
How long does Spray Foam last?
A lifetime.
What does Spray Foam Insulation do?
Keeps Outside air out and Inside Air In!
What is Spray Foam?
Spray foam is a two-part mixture is applied by trained professionals to the surface to be insulated. The spray mixture expands rapidly to fill all cracks and voids, completely and permanently adhering to wood, masonry, metal, concrete, and most other construction materials.  As a result, spray foam keeps the heat inside during the cold months and the hot air outside when it’s warm.
Are there any incentives available to insulate?

Yes! Federal income tax credits may provide up to $1,200 each year to lower the cost of energy-efficient home upgrades. Check out our Tax Credits and Rebates page to learn more.

Local utility providers like CPS Energy also offer rebate programs for current customers. Also be sure to check out the Database of State Incentives for Renewables & Efficiency to see if you qualify for energy rebates.

What is R-Value?
The “R” in R-value stands for resistance to heat flow. The higher the R-value, the higher the level of resistance and the greater the insulating power. R-value requirements vary depending on climate and building type.
What R-Values are recommended for homes in this area?

The amount of insulation needed varies depending on location, building type and materials. We can provide more information about the recommended R-Value once we discuss your project scope. Click here to view recommended home insulation R-Values in the U.S.

Which insulation product is the best?
Every insulation job has its own unique set of requirements, and every homeowner has their own budget guidelines. To make an informed decision, it’s important to talk to a knowledgeable insulation expert so you can learn exactly what options are best for you. Contact South Texas Insulation to discuss your specific needs.