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rafter


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One of several long, inclined, rectangular timbers used in the construction of pitched roofs, supporting the roof-covering, e.g. laths and tiles. Types of rafter include:angle rafter:principal rafter under the hip rafter carrying the purlins on which the common rafters rest. In the USA any rafter at the angle of a roof, whether principal or not, hence either a hip- or jack-rafter in a valley;auxiliary rafter:in a truss, a rafter used to stiffen the principal by doubling it;binding rafter:purlin;common rafter:of uniform dimensions, placed at regular intervals along the sloping section of a roof, sometimes as intermediate members between principals. A pair of common rafters is a couple;compass rafter:one curved on the lower side, or wholly curved, as in a truss;compound rafter:two rafters, one set over the other, separated by cleats, distance-pieces, or spacers, the inner rafters being secondary rafters;hip rafter:one set diagonally at the hip of a roof where two slopes at 90° join, supporting the upper ends of the common rafters;jack-rafter:1. One set diagonally at the valley of a roof where two slopes join, such as at a dormer-window roof, supporting the lower ends of common rafters. 2. Shorter common rafter between wall-plate and hip-rafter, or between a valley and the ridge;principal rafter:large rectangular inclined timber in a sloping roof supporting a purlin and also serving as a common rafter. A principal rafter not serving as a common rafter is a principal;valley rafter:one set diagonally where two roofslopes meet in a valley, e.g. at a dormer-window, as in jack-rafter1;verge rafter:common rafter set beyond a gable to support the roof-covering beyond the naked of the wall, itself supported on the ends of projecting wall-plates and purlins.

angle rafter:principal rafter under the hip rafter carrying the purlins on which the common rafters rest. In the USA any rafter at the angle of a roof, whether principal or not, hence either a hip- or jack-rafter in a valley;

auxiliary rafter:in a truss, a rafter used to stiffen the principal by doubling it;

binding rafter:purlin;

common rafter:of uniform dimensions, placed at regular intervals along the sloping section of a roof, sometimes as intermediate members between principals. A pair of common rafters is a couple;

compass rafter:one curved on the lower side, or wholly curved, as in a truss;

compound rafter:two rafters, one set over the other, separated by cleats, distance-pieces, or spacers, the inner rafters being secondary rafters;

hip rafter:one set diagonally at the hip of a roof where two slopes at 90° join, supporting the upper ends of the common rafters;

jack-rafter:1. One set diagonally at the valley of a roof where two slopes join, such as at a dormer-window roof, supporting the lower ends of common rafters. 2. Shorter common rafter between wall-plate and hip-rafter, or between a valley and the ridge;

principal rafter:large rectangular inclined timber in a sloping roof supporting a purlin and also serving as a common rafter. A principal rafter not serving as a common rafter is a principal;

valley rafter:one set diagonally where two roofslopes meet in a valley, e.g. at a dormer-window, as in jack-rafter1;

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Subjects: Architecture.


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