Breaking Down the Radiant Barrier Application Process

A lot of work goes into installing radiant barriers in your attic space—it isn’t quite as easy as just rolling out a sheet of tinfoil and hoping your cooling costs go down. 

Radiant barriers work by deflecting the sun’s rays, rather than typical thermal insulation which absorbs heat. When installing radiant barriers, thought needs to be put into the way they’re positioned. 

 Radiant barrier application can be done in several different ways, each with benefits and drawbacks. Consider the shape of your attic, whether you are using your attic floor for storage, and the climate you are in. Let’s discuss. 

Applying Radiant Barriers to Your Attic

Before installing radiant barriers in your attic, you will need to measure and cut out each sheet to meet the dimensions of the crawl space you are looking to cover. Radiant barrier application is a multi-person project—if you are applying barriers to the rafters, each sheet to be pulled so they remain somewhat taut after stapling them to the rafters. 

They don’t need to be airtight, but shouldn’t sag in between rafters either.

Some room should remain between the lowest sheet and the floor, as well as the top of the attic. This is for ventilation purposes, something that must be considered during the installation process. Each sheet should overlap the other by about an inch for maximum coverage. 

Open vents must remain uncovered for maximum air flow, and cuts in the attic radiant barrier can be made around any obstructions like water pipes that prevent forming an even surface area.

That being said, there’s more to radiant barriers than installation—you’ll need a plan designed around the way you live. Roofing specialists have different strategies depending on the geographic region they operate out of. 

Decide on your strategy before you make the first cut.

The Three Methods of Radiant Barrier Application

There’s more than one way to install radiant barriers to your attic, but each comes with perks and drawbacks. There are three common methods of radiant barrier application:

  • Open-Ridge or Staple-Up Method
  • Over-Insulation or Over-Ceiling Method
  • Hybrid Method

The basic difference between these three methods is whether radiant barriers are stapled to the rafters of the attic or if they are laid out on top of the insulation material between the joists. 

The hybrid method incorporates both.

Choosing the method that is right for you begins with checking whether you have ductwork in the attic. These are most commonly found in older homes. If you live in a home like this, you will want to attach radiant barriers to the rafters. This will keep your air conditioning from working to the point of breaking during the hottest months.

Another factor to consider is whether you are using your attic for storage purposes. If you need that extra space for odds and ends, applying radiant barriers to the floors alone will not be an effective method of keeping your home cool, and will overheat whatever you’re keeping in the attic.

With these considerations in mind, let’s look in depth at these barrier application methods, and how they can cut cooling costs in your home.

#1 Open-Ridge Method

The open-ridge type of radiant barrier installation is a method of applying heavy duty radiant barriers between the rafters, forming a protective shield that keeps your attic area cooler during the hottest months.

For people that use their attics for storage, or have any kind of ductwork and HVAC systems installed, applying this method has been shown to be an effective means of returning value on your investment.

When installing radiant barriers, make sure to clean all surfaces of the attic before placing them adjacent to the undersides of the rafters. If dust is able to accumulate on the surfaces of radiant barriers, they tend to be less effective.

For people living in hot climates like San Diego and Orange County, an open-ridge method should be considered the bare minimum for any kind of radiant barrier installation. Radiant barriers are most effective when they reflect back the rays of heat at the angle they are hitting the roof, making this method suitable for that climate.

Takeaways from the Open-Ridge Method

Open-Ridge Insulation is ideal for those living in hot regions or those who have ductwork in their attics, and tends to be the go-to method of radiant barrier application. 

Installation may require expert help to reach high or hard-to-reach areas.


  • Keeps attic open for storage purposes
  • Best in hot, sunny climates like San Diego and Orange County where reducing cooling costs is primary concern
  • For attics with ductwork and HVAC systems, produces greatest cost savings


  • Installation is more difficult than Over-Insulation Method
  • Covers greater surface area than laying it down, increasing initial cost
  • Requires higher-end materials so radiant barriers can remain stapled up

Over-Insulation Method

The easiest way to install radiant barriers, the over-insulation method simply involves draping radiant barriers over the joists and any existing insulation between them. This is also called the over-ceiling method, as it covers the space directly above your ceilings below the attic.

Aside from easy installation, this method is popular in houses in the Midwest as it is able to keep radiant heat inside of the home during the winter (as well as repel it during the summer months).

So, given that this method is the least labor intensive and cheapest means of installing radiant barriers, shouldn’t you be using it? 

The simplicity of this method may be alluring, but comes with many drawbacks. 

For one, attic spaces with this type of radiant barrier can’t be used for storage. Rather than reducing the heat in your attic, it will become even hotter than before. If you have any sort of ductwork or HVAC systems, they will have to work even harder to cool down your home.

Because the floor of your attic will be covered by a shiny metallic material, navigating joists when walking in an unfinished attic will be challenging. The over-insulation method radiant barrier application is not recommended for the accident prone.

Takeaways from the Over-Insulation Method

Simple to install, the over-insulation method works well in climates that require both heating and cooling throughout the year. 

It is recommended for homeowners in variable climates, but requires dusting to maintain its reflective properties throughout the year, and leaves no room for storage.


  • Easy installation
  • Least amount of radiant barrier material required to install
  • Reduces cooling costs in summer and heating costs in winter
  • Best in climates with seasonal weather patterns, such as the Midwest


  • Attic space cannot be used for storage
  • You will not be able to see joists—unfinished attics may be perilous to walk around in
  • Accumulation of dust will require periodic cleaning of radiant barrier surfaces
  • Not recommended in attics with ductwork and HVAC systems

Hybrid Method

The hybrid method combines the best of both worlds, covering the whole surface of your attic while providing maximum cooling efficiency. 

This means the rafters, insulation, and joists will all be covered in radiant barrier material. It is gaining popularity among homeowners as the most effective method of attic radiant barrier installation.

The best attribute of the hybrid method is that you will ensure that your home is protected against the elements in all seasons, and your attic will keep down heating and cooling costs at maximum efficiency. 

No matter what the weather throws at you, your home will remain comfortable.

Although your floor will be covered in radiant barrier material, it can still be used for storage purposes, as the attic temperature will be regulated from all sides. Some of the issues that come with using the over-insulation method will remain, but it guarantees that cooling costs will stay at their lowest possible level.

Takeaways from the Hybrid Method

The most all-encompassing form of radiant barrier protection, the hybrid method works in all seasons and conditions. It is the gold standard of attic temperature control. 

If heating your home in the winter is never an issue, this method may be excessive, but in all other cases, you can’t go wrong with this method of cooling cost reduction.


  • Maximizes cooling efficiency from radiant barriers
  • Lowers heating and cooling costs throughout every season
  • Allows ample room for storage
  • Perfect climate for ductwork and HVAC systems


  • Most expensive and labor intensive
  • Requires highest square footage of radiant barrier material
  • Joists will be obscured, and ground area will require periodic dusting

Should I Install Radiant Barriers Myself, or Hire Experts?

You can install radiant barriers alone, but doing so requires a great deal of planning and expertise. 

Why not leave it to people who do it for a living?

Attic Construction has been providing residents in San Diego and the Orange County area with services like attic insulation, attic cleaning, rodent decontamination, and radiant barrier installation since 2017. We pride ourselves on our excellent service and competitive pricing.

Contact us today and receive a free attic inspection appointment to see if radiant barriers are right for you! Our customers will receive a $300 discount off all radiant barrier installation services.


  1. Oak Ridge National Laboratory. Radiant Barrier Installation.
  2. Attic Foil. Best Install Method.
  3. Innovative Insulation. Radiant Barrier Installation Methods.

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