Roof Surface Temperature Calculation

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Roof surface temperature calculation.

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. Calculating the surface area of a sloped roof can be time consuming without the right tools. 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 following tools estimate the area of a roof as well as the amount of materials necessary to construct a roof of a given area.

You want a roof area calculator that provides accurate estimates to help you order materials such as shingles membrane roofing or ceramic tile. To compute solar reflectance index sri and roof surface temperature based on solar reflectance r and thermal emittance e using astm standard e 1980. Ambient conditions and reference surface properties specified in next worksheet. The length l times the height h of a triangle is twice its area a2.

The rooftop temperature results from two different properties. 20 cm of cellular concrete. 1 roof square 100 square feet. 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.

Area is defined as the expanse or measurement of a given surface and there are a few methods for measuring your roof s area. Ts to a id is hso a absorption coefficient of outside surface id direct solar radiation on surface. Input r and e in blue and green cells. An approximate equation for the sol air temperature ts of the outside surface of a given wall or roof is.

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. 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. 7 5 cm of cellular concrete representing the top slab and the topping 2. Click on the red button to compute sri and roof surface temperature.

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.