Drainage walls allow water that leaks into the wall to drain out such as cavity walls. Barrier walls are designed to allow water to be absorbed but not penetrate the wall, and include concrete and some masonry walls. Types of wall systems with regard to water penetration are barrier, drainage and surface-sealed walls. Walls do not get as severe water exposure as roofs but still leak water. Domestic roof construction may also be ventilated to help remove moisture from leakage and condensation. Typically residential, pitched roofs are covered with an underlayment material beneath the roof covering material as a second line of defense. Pitched roofs are designed to shed water but not resist standing water which can occur during wind-driven rain or ice damming. Flat roofs actually slope up to 10° or 15° but are built to resist standing water.
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Two broad categories of roofs are flat and pitched. One of the main purposes of a roof is to resist water. Water and water vapor control Ĭontrol of rain is most fundamental, and there are numerous strategies to this end, namely, perfect barriers, drained screens, and mass / storage systems. The control function is at the core of good performance, and in practice focuses, in order of importance, on rain control, air control, heat control, and vapor control. Finish (to meet desired aesthetics on the inside and outside).Control (the flow of matter and energy of all types).Support (to resist and transfer structural and dynamic loads).
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The many functions of the building envelope can be separated into three categories: Building envelope design is a specialized area of architectural and engineering practice that draws from all areas of building science and indoor climate control. The building envelope (or the more modern term, building enclosure) is all of the elements of the outer shell that maintain a dry, heated, or cooled indoor environment and facilitate its climate control.