roof types styles and shapes

Pitched roofs are normally clad with slates or tiles. Such Roof types have to be strongly constructed to support the immense load of the states or tiles as well as any snow that settles. Moreover, the roof is exposed to the wind, which can exert a large force in exposed areas. How they are built? There are two common roof types for a pitched roof. If the roof has just a simple slope on each side, meeting in a ridge like a tent, it is said to be two—way pitched. The walls at the ends of a two-way pitched roof are the gable walls, and are often triangular in shape at the top. It is usual for the roof to project slightly beyond, and be supported by, the gable wall. The end of the roof is concealed behind bargeboards, which are nailed to the end rafters. The roof projection beyond the gable is the verge which shields the top of the wall from the rain. On some houses, the gable wall extends higher than the ridge. In such cases the gable is square at the top, capped oft with a stone coping or rendering. This type of wall, against which a roof abuts, is an abutment wall. The other common roof types of roof shape is called a hipped roof. It is formed when the roof has a third slope, rising from the end walls to the top like the side of a pyramid. Some houses have both types of roof joined in one: for instance a house that is L-shaped in plan may have a two way roof on one leg of the L, but a hipped roof on the other; a T-shaped house, too, may have hips at the two ends of the roof covering the top cross-member, but a two-way pitch at the end of the main T-section; a hipped roof may have a dormer window with a two-way pitched roof; and there are other variations. Another type of pitched roof you may see occasionally is the mansard. In this the pitch is at two angles a gentle one at the top and a steeper one below, nearer the outer wall. Often, these roof types were designed to allow a room in the attic. They were, in fact a cheap way of getting an extra storey, for the lower parts of such a roof are more easily and cheaply built than a brick wall.

roof types styles and shapesLean-to buildings, verandahs and porches often have a single sloped roof covered by tiles and slates. These are known as mono pitch roofs. Traditionally, the frame for a pitched roof was built up on site by skilled joiners. On pitched-roof houses built since about 1950, however, the triangular frame is of a missed rafter construction. With these, the triangular frames are constructed as a whole in a factory, and brought to the site looking much like giant coat hangers. They are strengthened by lengths of timber known as trusses. The difference between a trussed frame and the traditional type is crucial if you ever think of building a loft extension. It is impossible to erect a room in an attic formed by trussed frames, for you cannot remove any of the middle trusses to clear a space for a loft conversion without seriously weakening the whole structure. lt is possible, however, to remove sections from an older-style roof, provided that compensating support is added elsewhere. But the subject of loft conversions is complicated and you should never attempt it without expert advice. Whichever construction method has been used, the frames are broadly similar. The lower member of the triangle is the joist, to the underside of which the ceilings of upstairs rooms are fixed. These joists are fixed to wall plates at the top of the main walls of the house, the two sides of the triangle are the rafters, and these are joined both to the wall plates and to the sides of the joists. At the top end, the rafters are joined to a horizontal length of timber known as the ridge board. Intermediate support for the rafters is provided by purlins, which are usually braced. Two methods of bracing are used.

There may be struts supported on an internal load-bearing wall, or hangers fixed vertically to the joists and further strengthened by runners extending vertically between the hangers. The purlins may be notched into the rafters, or just beveled to suit the angle at which they meet. The rafters project well beyond the eaves and are finished off by two lengths of timber. The one underneath the rafters is the soffit board, and the other to which the gutters are fixed is the fascia. Sometimes the eaves are left open. Never block off open eaves as a draught-proofing or insulation measure. They are left open to keep the loft well ventilated and dry. Blocking off might encourage condensation, which will dampen and rot the roof timbers and saturate any loft insulation, rendering it ineffective. Houses built with blocked off eaves have compensating ventilation elsewhere. Older houses often have a front external wall extended to form a parapet. This is sometimes topped with a stone coping. The parapet has a damp-proof course, two or three courses from the top to stop moisture being conducted from the parapet to the main walls of the house. In such instances, a gutter as such is not installed; gutter boards are used to form one artificially. A parapet wall hides the roof from view. Often the roof types behind it consists of two small pitched roofs which are joined to form a valley, which serves as a gutter to collect water from the two inner pitches. The two parts of a valley roof do not need to be as high as would a single, pitched roof covering a house of the same size. This, with the fact that they are concealed behind a parapet, ensures that they are sheltered from some of the effects of the weather. An unfortunate consequence of the lower height, however, is that there is not much headroom beneath them should you ever have to do work up there.