But this has been exacerbated by human activities which have led to: 1) an increase in greenhouse gas emissions that causes heat to remain trapped within the troposphere, and 2) a decrease in ozone in the stratosphere, causing less sunlight to be absorbed by the ozone layer, resulting in a cooling of the stratosphere.
When measuring for floor tile the rule is: Length x Width + Waste = Amount Needed. Waste Factor will vary based upon tile size, layout, configuration of room, patterns, etc. Typical waste factor is about 10%. Add 15% for tile being installed diagonally or for a room with lots of jogs and corners.
Calculating Guide for Roofing Sq. Footage. Substitute the formulas given under each type of roof to obtain actual square foot area for the following roofs. Formula refers to shaded area in diagram. Add 10% approximate extra for waste. 1.Multiply length x width of building; include overhangs.