Click on the red button to compute sri and roof surface temperature.
Roof surface temperature calculation.
An approximate equation for the sol air temperature ts of the outside surface of a given wall or roof is.
To compute solar reflectance index sri and roof surface temperature based on solar reflectance r and thermal emittance e using astm standard e 1980.
Calculating the surface area of a sloped roof can be time consuming without the right tools.
Area is defined as the expanse or measurement of a given surface and there are a few methods for measuring your roof s area.
The rooftop temperature results from two different properties.
Ambient conditions and reference surface properties specified in next worksheet.
Ts to a id is hso a absorption coefficient of outside surface id direct solar radiation on surface.
This calculator produced by lawrence berkeley national labs lbnl allows you to compute solar reflectance index sri and roof surface temperature based on solar reflectance and thermal emittance based on astm standard e 1980.
You want a roof area calculator that provides accurate estimates to help you order materials such as shingles membrane roofing or ceramic tile.
The base width is the distance from one corner of your roof to the other at its base on the short side of your house.
7 5 cm of cellular concrete representing the top slab and the topping 2.
1 roof square 100 square feet.
The ability of the material to reflect the sun s energy back into the atmosphere called solar reflectance and the amount of heat the material rejects instead of absorbs called thermal emittance both are measured on a scale from 0 to 1 with higher scores translating into cooler roofs.
Our roof calculator uses base length and base width to find the estimated area.
The following tools estimate the area of a roof as well as the amount of materials necessary to construct a roof of a given area.
The length l times the height h of a triangle is twice its area a2.
For the calculation of surface temperature and heat flux the roof figure 1 was approximated by three homogeneous layers figure 2.
20 cm of cellular concrete.
Once you work through the basic triangle we will review a typical roof and how to apply some simple math to calculate how much material you will need for a roof used in our hypothetical example.
Input r and e in blue and green cells.
Start the project with a roof area calculator.
