Reflection is a material property
Solar reflectance describes how much solar radiation is reflected from a surface. Thermal emission describes how absorbed heat is released. SRI combines both into one comparison value.
Preferably use documented measurement values for the chosen white variant. A white color without test information is not complete technical substantiation.
Do not promise a fixed number of degrees
The indoor temperature is also determined by insulation, ventilation, glass, internal heat load, roof shape and use. Therefore, a reflective roof can be useful without a universal temperature or saving percentage being guaranteed in advance.
For living spaces directly under the roof, the effect may be different than for a well-insulated garage or unheated extension.
Waterproofing remains the main performance
A Cool Roof must first be a reliable roof. Substrate, primer, seams, curbs, drains, layer thickness and maintenance therefore remain part of the system choice.
Pollution and aging can reduce reflection. Periodic inspection and cleaning must be practically possible.
- Documented white variant
- Complete waterproofing structure
- Maintenance and pollution
- Building-specific expectation
- No loose energy promises
This explanation is general and does not constitute project-specific system advice. Subsurface investigation, tax and official system documentation remain decisive.