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Practical Roof Solutions

Hipped Ends
The good performance of MiTek designed hipped ends does not depend on tension in battens, a massive wallplate and horizontal thrust on walls. Indeed, with suitable bracing, walls are provided with the stability called for by the Building Regulations. The most simple and lowest cost form of MiTek hipped end, (shown in figure 11a) consists of a multi-ply girder of standard trusses securely fixed together and supporting loose rafters and
ceiling joists. Such constructions are limited to spans generally not exceeding 5m. Sizes of rafters and ties can be found in approved document 'A' of the Building Regulations. Hip boards should be
supported off the girder by means of a ledger and the ceiling joists by means of proprietory joist hangers. 
The 'step-down' system incorporates flat-top hip trusses of progressively diminished height from the ridge to the girder. The number of step-down trusses is determined by the necessity of maintaining reasonable sizes for the loose ceiling joists and hip board on the hipped corner infill areas, as shown in figure 11b. For these reasons the span of the monopitch trusses is not usually greater than 3m in the case of regular hips (where the end pitch is the same as the pitched of the main roof).
Noggings have to be fitted between the flat chords of the step-down hip trusses to support the tiling battens. The web configurations of the various truss types shown (including the mono-pitch) are typical but will be chosen to provide the best structural solutions.
This step-down hip system is no longer very popular as it requires many different truss profiles to be made. 
The 'flying rafter' hip system show in figure 11c has the manufacturing advantage of there being only one basic hip truss profile. All of the hip trusses, including those forming the girder are similar, and the mono-pitch trusses supported off the girder usually have the same profile as the sloped part of the hip trusses which speeds up fabrication.
The rafters of the mono-pitched trusses are site cut to sit against the upper hip board and the off-cuts are nailed in position to the rafters of the hip trusses. The flat parts of the top chords of the hip trusses and girder are well braced together to prevent instability.
While the hipped corner infill is shown as prefabricated rafter-joist components (open jacks), it is usually cheaper to site fabricate in these areas. The lower hip board is typically notched and supported off a 50 x 50mm post nailed to the girder truss. The upper hip board can be supported off ledgers and in some cases is propped off the hip trusses underneath. 
The system offers the advantage of continuous rafters and consequently easily constructed smooth roof slopes. On long spans it may be necessary to use a second hip girder between the apex and monos.