Radiant Barrier OSB: Reflective Sheathing Solutions for Los Angeles

The summer heat in Los Angeles creates a challenging environment for builders who must also follow the demanding Title 24 energy code standards. Radiant barrier oriented strand board (OSB) sheathing provides structural support through its OSB core, while its reflective foil layer helps maintain cooler temperatures in attics and living areas. The specialized panel functions by reflecting radiant heat instead of absorption. This leads to reduced heat transfer, decreased cooling requirements, and enhanced indoor comfort in places like San Fernando Valley, Pasadena, and Downtown LA neighborhoods.

Standard OSB sheathing maintains structural integrity and dimensional stability yet it does not provide any thermal insulation benefits. The thin aluminum coating in radiant barrier OSB reflects 97 percent of solar radiant energy, which results in attic temperature reductions of 30 °F and leads to potential cooling cost reductions of 17 percent in hot climates. The following table enables you to evaluate the need for reflective barriers in your Los Angeles construction project.

What Is Radiant Barrier OSB?

Radiant barrier OSB is a structural sheathing panel composed of oriented strand board with a foil layer bonded to one face. The wood portion is produced from strands of small, fast‑growing trees pressed with resin to form a stable panel. 

During manufacture, a heat‑reflective aluminum foil is laminated to the underside of the board. When installed with the foil facing into the attic, the panel reflects radiant heat rather than absorbing it. According to building‑science studies, radiant barrier sheathing must have an emissivity of 0.1 or less, meaning it emits less than 10 % of the heat striking it.

How Radiant Barrier OSB Works

Heat from the sun warms roofing shingles, which then radiate heat through the roof deck into the attic. In a conventional roof assembly, the plywood or OSB sheathing absorbs this heat and allows it to pass into the attic. Radiant barrier OSB interrupts this transfer by reflecting the energy away from the attic and re‑emitting only a small fraction of it. 

Tests show that a properly installed radiant barrier can keep attics up to 30 °F cooler and reduce air‑conditioning requirements by half a ton, while lowering overall cooling costs by 10–17 %. Because attic ductwork and insulation stay cooler, HVAC systems run more efficiently and last longer.

Benefits of Radiant Barrier OSB in Los Angeles

• Improved energy efficiency: Reflects up to 97 % of radiant heat, lowering attic and living‑space temperatures in hot LA neighborhoods like the San Fernando Valley and Pasadena.
  
  

• Reduced cooling costs: Can reduce cooling loads by up to 17 % and may allow smaller HVAC equipment, saving money on utility bills.
  
  

• Code compliance: Helps meet Title 24 and Energy Star requirements for energy‑efficient building envelopes.
  
  

• Enhanced comfort: Decreases temperature swings and hot spots in upper floors, creating a more comfortable environment.
  
  

• Longer service life: Reduces thermal stress on roofing materials, ductwork and insulation, extending their lifespan.

Applications and Installation Tips

Radiant barrier OSB is suitable for most residential and light‑commercial roof and wall assemblies. It works particularly well in new construction but can also be installed during roof replacement projects. Use it for sheathing on homes in valley areas such as Burbank and Glendale, where high summer temperatures drive up cooling loads, and in coastal communities like Santa Monica, where reducing attic heat still improves comfort.

To maximize performance, follow these installation guidelines:

1. Face the foil toward the attic. Install panels foil‑side down, facing the attic or conditioned space. The OSB side should face the roof covering, and the APA trademark should be visible on the exterior face.
   
   

2. Allow expansion. Maintain a 1/8‑inch gap between panels at joints to accommodate thermal expansion.
   
   

3. Ventilate the attic. Provide proper attic ventilation so that heat building up at the foil surface can escape; a well‑ventilated attic improves cooling performance.
   
   

4. Seal penetrations. Seal ductwork and openings through the sheathing to prevent air leakage and maintain the radiant barrier’s effectiveness.
   
   

5. Protect during installation. Cover the OSB side with roofing felt or underlayment as soon as possible to protect the panel before final roof installation.

Sourcing and Delivery in Los Angeles

Supply Ontime provides reliable delivery across the Greater Los Angeles area. Customers can count on:

• Same‑Day or Scheduled Delivery
  The company provides same-day delivery service for urgent framing needs and allows customers to schedule deliveries in advance for bigger projects. The system delivers materials at the exact time construction workers need them, which prevents delays and maintains project timelines.
  
  

• Flexible Unloading Options
  Deliveries can be handled in multiple ways depending on the site. Truck Bed delivery works for lighter items; Curbside delivery keeps drop‑offs simple within 5 feet of the truck; and White Gloves service places materials at the doorway for added convenience.
  
  

• Clear Delivery Rates
  Pricing is weight‑based and transparent, so there are no surprises. Customers know up front what it will cost to have materials delivered, whether it’s a small order under 20 lbs or a large shipment requiring specialized handling.
  
  

• Convenience at Drop‑Off
  The delivery process needs to remain simple for all delivery options that customers select. The materials can be unloaded from the truck either by placing them at the curb or by staging them at the first entrance of the building. The system provides flexibility, which enables construction teams and homebuilders to concentrate on building activities while avoiding logistical concerns.

Explore Supply Ontime’s monthly Proof of Delivery updates to see real examples of completed orders across Los Angeles.

Final Thoughts

Radiant barrier OSB offers Los Angeles builders a simple way to increase energy efficiency and indoor comfort without changing their structural framing practices. By reflecting solar radiation away from the attic, these panels keep homes cooler, lower utility bills and help meet Title 24 requirements. When combined with proper ventilation, insulation and weather‑resistant finishes, radiant barrier sheathing can be a cost‑effective investment in comfort and sustainability.