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Attic Frames 2 & 3 Part Construction
All the trusses (or frames) are generally of two basic types depending on how they are supported.

Type 1:
(Figure 98a) is characterised by a load-bearing support at or near mid-span and as a result generally has heavy joists propping relatively light rafters. The truss may need to be supplied in kit form for completion on site if it is too high for fabrication or
transportation. The kit form, while requiring some site fabrication, does make for straightforward erection as the floor joists can be installed first, providing a safe, rigid working platform.
Type 2:
(Figure 98b) is free spanning between wallplates and as a result the floor is suspended from the rafters which consequently are relatively heavy and often as heavy as the floor joists. The associated kit form is usually different to that for type 1 in order to facilitate erection and to ensure that the more important joints are made under factory controlled
conditions. However, substantial connections, often employing MiTek field splice plates, fully nailed or bolts, have to be made between the capping and base components, handling and erection of these heavy units needs to be carefully supervised.