Input r and e in blue and green cells.
Roof surface temperature calculation.
To compute solar reflectance index sri and roof surface temperature based on solar reflectance r and thermal emittance e using astm standard e 1980.
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.
Click on the red button to compute sri and roof surface temperature.
1 roof square 100 square feet.
The house base area is the area of land that the house covers and for more complex shapes can be estimated using the area calculator.
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.
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.
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.
Area is defined as the expanse or measurement of a given surface and there are a few methods for measuring your roof s area.
Start the project with a roof area calculator.
Your job is to calculate and illustrate the temperature gradient through a roof assembly composed of a gravel surfaced built up roof 3 4 inch thick perlite insulation 2 inch thick polyisocyanurate insulation two ply felt and asphalt membrane vapor retarder 1 2 inch thick gypsum board and metal deck.
7 cm dead air space ventilation and spacer blocks ignored 3.
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.
The length l times the height h of a triangle is twice its area a2.
7 5 cm of cellular concrete representing the top slab and the topping 2.
The rooftop temperature results from two different properties.
An approximate equation for the sol air temperature ts of the outside surface of a given wall or roof is.
You want a roof area calculator that provides accurate estimates to help you order materials such as shingles membrane roofing or ceramic tile.
Our roof calculator uses base length and base width to find the estimated area.
Ambient conditions and reference surface properties specified in next worksheet.
