The 2019 updates to California’s Building Energy Efficiency Standards for Residential and Nonresidential Buildings updated the previous version’s standards for insulation and cool roofing in California.
Understanding how to achieve California requirements for roof insulation and cool roofs is key to a successful roofing project.
Title 24’s California roof insulation requirements for the roof and ceilings differ between residential and nonresidential applications. In all buildings, wet insulation systems are required above the roof's waterproof membrane. Consulting the code directly will ensure that you’re meeting all of the required standards, including above deck roof insulation requirements for California.
What Is A Cool Roof?
A cool roof is designed with energy efficiency in mind. The main feature of cool roof rated materials, as designated by the Cool Roof Rating Council (CRRC) is their ability to reflect, rather than absorb sunlight, and efficiently emit heat that is absorbed. This saves energy by reducing the amount of air conditioning necessary to effectively cool a building as well as extending the service life of the roof by decreasing the roof temperature, among other benefits.
In order to qualify as a cool roof, the roofing material must meet the standards set out by the CRRC for reflectance and thermal emittance. Inclusion in the ENERGY STAR® list of roofing material does not qualify roofing materials as cool roof materials.
Luckily, the price of cool roofing materials is comparable to conventional roofing materials and will save on energy costs, to effectively lower the cost of the roof even further.
When Is A Cool Roof Required?
The update requires a cool roof on new construction as well as on some reroofing projects. In residential buildings, if 1,000 sq. ft. or more of the roof is being added or retrofitted on an existing roof, cool roofing materials are required. For nonresidential buildings, a cool roof is required if the retrofits or additions replace or recoat 2,000 sq. ft. If the retrofit or addition is 50% or more of the existing roof, a cool roof or cool roof coating is required.
If the roof uses conventional roofing materials, it is possible to coat the roof with a cool roof coating to increase its ability to reflect solar energy.
Benefits Of Cool Roofs
Reduced Energy Costs
Cool roofs reflect sunlight back into the atmosphere rather than absorbing it into the structure. This reduces cooling costs, since the interior of the building remains cooler than if a standard roof was used.
Reduced Air Pollution And Greenhouse Gasses
By lowering the amount of energy needed to cool the structure, cool roofs by extension decrease the emission of greenhouse gas and air pollution.
Improved Comfort And Safety
Reduced air temperatures inside the home can create a more comfortable and safer environment for those with and even without air conditioning. Cool roofs can have an impact on lowering heat- related deaths.
Available In A Range Of Colors
While white roofing reflects about 60-90% of sunlight, it is possible for darker colors to reflect sunlight when special pigments are used that reflect invisible “near infrared” radiation. These cool-colored products can reflect about 30-60% of sunlight, which allows them to stay cooler than standard colored products.
Lessens The Urban Heat Island Effect
Urban areas can get hotter than their surrounding rural areas, leading to consequences that include people suffering from heat exhaustion or dehydration as well as higher energy costs to cool buildings. When enough buildings in an area have cool roofs, the overall effect can lower the temperature in that area.
Drawbacks Of A Cool Roof
Heating Costs Could Be Higher
The purpose of a cool roof is to reflect sunlight back into the atmosphere, so it works to reduce the interior temperature of a building. In the winter, this could result in higher heating bills, but in California’s warm winter climate, the effect isn't very high.
Algae And Mold May Be More Visible
If the coof roof accumulates algae or mold growth, it could be more visible on the lighter color than it would be on a darker colored roof.
Condensation Can Lead To Moisture Accumulation
Moisture is the enemy when it comes to structural integrity, including roofing materials. Cool roofs can be more likely to accumulate moisture as a result of condensation than dark roofs, but there are design techniques that can help reduce this risk.
How To Achieve California’s Title 24 Roof Insulation And Cool Roof Requirements
The easiest way to achieve a cool roof in California is to choose cool roof material when building a new home or nonresidential building. Materials that can achieve cool roof design include light colored asphalt, wood, composite, clay, and concrete roof tiles.
Using composite roof tiles to achieve a cool roof comes with a number of benefits:
Lightweight materials don’t put extra strain on the structure like clay or slate tiles.
No maintenance is needed.
They have a Class A fire rating for superior fire resistance.
They have a Class 4 impact rating allowing them to stand up to impacts from hail and debris.
They won’t become brittle or rot over time.
They are sustainable and fully-recyclable.
All of Brava’s products use recycled materials, and our goal is to keep as many used building materials out of landfills as possible.
Composite shingles mimic the look of natural wood, clay, and slate shingles, to give you a traditional look without the downsides.
A choice of colors gives you the option to customize the look of the structure.
Contact the experts at Brava today to discuss our cool roof options for your California project.