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Knowing what R-value indicates is key to choosing the right insulation products that best suit your climate and your home’s energy needs.

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Heating and cooling account for close to 50% of the total energy use in many North Carolina homes. Inadequate basement or crawl space insulation and air leakage through the attic are the leading causes of energy inefficiencies. Basement or crawl space insulation provides an effective way to reduce your energy costs and improve the comfort of your home. But, to get the most out of your insulation, you need to understand what exactly an R-value is and its effect on your insulation. 

What Is R-Value? 

R-value is a measure of an insulation material’s thermal resistance. The “R” in R-value stands for resistance to heat flow. Therefore, the higher the R-value of a material, the stronger its insulation power. The R-value of insulation depends on the type of insulation, its density, and thickness. Other factors that influence R-value include: 

  •  A material’s age 
  • The temperature 
  • Moisture concentration 

Types of Insulation 

The following materials are most commonly used for basement or crawl space insulation in North Carolina: 

  • Batts and rolls: They come as flexible fibers like fiberglass, plastic fibers, natural fibers, and mineral wool. Batt and roll insulation are good for areas with unfinished spaces like basement walls, floors, and ceilings. Additionally, they can be used between wall studs, floors, and ceiling joists. The R-value of a particular batt and roll insulation material will depend on its size. Fiberglass batts, however, are very absorbent and easily retain moisture that can lead to mold and pest infestation. 
  • Rigid foam: This type of insulation is made of polystyrene, polyurethane, or polyisocyanurate materials. It has a high R-value and can insulate almost any part of the home, including basement or crawl space walls. Apart from retaining heat, rigid foam also resists moisture that tries to go through your basement or crawl space walls. 
  • Insulating concrete forms: When poured concrete walls are being erected, the builder can integrate these insulators into your wall. They will remain part of the wall assembly, creating walls with high thermal resistance. 
  • Sprayed foam: Here we have phenolic, polyisocyanurate, polyurethane, and cementitious. This type of insulation is suitable for covering a finished basement. 

Areas That Need Insulation 

Many parts of your home need to be insulated. Let’s look at some of the critical ones. 

Roof and Attic 

Because heat escapes through the ceiling and attic, roof and attic insulation are vital. Attic insulation improves winter comfort and energy efficiency. In the summer, attic insulation protects your home against heat gain radiating through the roof and down into your living space. Thick batts of fiberglass are usually installed between the joists to prevent heat loss. 

Exterior Walls 

During home construction, builders add fiberglass or spray foam insulation between the studs. While this helps protect the building against heat loss, a significant part of the wall will still be left uninsulated. Wood studs make up 25% of an entire basement wall. Since they aren’t insulated, the perfect opportunity for heat transfer is created. Insulating the exterior walls of your home helps to stop energy loss. 

Unencapsulated Crawl Space  

A crawl space that lacks proper encapsulation or insulation pulls heat out of the house. During winter, it is common to have cold floors above the crawl space.  

ExTremeBloc™ is our natural choice for insulating the crawl space walls. Two inches thick, this material radiates heat to the crawl space for energy savings. Not only does it reflect heat, but it has a superior R-value and a class A fire rating. In addition, it contains termiticide which deters termites from damaging your insulation. 

We don’t advocate for fiberglass batts for crawl space insulation as they tend to soak up moisture, which can cause them to develop mold and sag or drop off the ceiling. 

Which R-Value Insulation Do You Need?  

Any material with an R-Value of 7 or above makes for good insulation material for the crawl space. Such insulation will reduce heat transfer to the outside. Various factors determine the type of R-value that your walls need, including your local weather, the type of HVAC unit you have, and which part of your house needs insulation. So, you can’t just go with the manufacturer’s values as they apply to properly insulated walls.  

Is Below-grade Area Insulation Necessary?  

Insulating your crawl space or basement is just as important as insulating the rest of the house but has a bigger payoff. The first and most valuable benefit of basement or crawl space insulation is that it makes your home more energy efficient. Your home will no longer be at the mercy of North Carolina’s temperamental weather. Other benefits of insulating these areas include:  

  • Less draft  
  • No more cold floors  
  • Greater indoor air quality  
  • Increased indoor comfort  

At Tar Heel Basement Systems, we specialize in professional basement or crawl space insulation. We use our highly innovative ExTremeBloc™ insulation panels, which are designed to resist water and moisture and provide you with greater comfort from the ground up. Should you need to repair your basement or crawl space insulation or upgrade these areas’ energy efficiency, contact us today for a free inspection.

Our Service Areas


2910 Griffith Rd
Winston-Salem, NC 27103


3333 Air Park Road
Fuquay-Varina, NC 27526