Surface finish

Large shiny surfaces in GRP will show warping when used extensively over large, flat elevations. Panels up to I m wide with a high gloss can be accommodated, but over that width, surface ripple may become apparent. This is not only a problem of GRP - even plate glass and aluminium sheeting suffer in this respect. For this reason, some surface treatment may be appropriate, such as a matt-textured finish. Within reason, the coarser the texture the more surface deflection it will accommodate. However; if the texture becomes too coarse, it can slow down the rate of lamination, increasing the cost of production. Probably the optimum finish is a riven slate texture created in the master pattern mould, which has all the advantage of accommodating surface deflection, while being economical to laminate. However; riven slate has the disadvantage that it is limited in size and therefore has to be panelled, though this does not necessarily create difficulties if designed with care.

Vinyl cloth is very good for producing a light striated panel. For example, panels for a store in Nottingham, shown under construction in Fig. 3.12, were produced with a matt surface after laying vinyl wallpaper onto the mould from which the production mould was manufactured. However; against this, vinyl cloth is available only in set widths, with resulting

difficulties in hiding the joints. Random spray-on textures have advantages when compound curves are a feature of the design.

It is not uncommon, because of the ease of moulding GRP panels, for them to be used in conjunction with other materials for solving special corner or flashing details. For example, at the factory at Winwick Quay, Warrington (architects: Nicholas Grimshaw Partnership) (Fig. 3.1 3), GRP corner panels are painted to match the silver-grey Alucobond aluminium sandwich panels.This mixing of materials can lead to problems of colour matching and difference in rates of colour change.

3.10 Olivetti Training Centre at Haslemere (architect: James Stirling).

3.10 Olivetti Training Centre at Haslemere (architect: James Stirling).

3.11 Panels at Herman Miller factory, Bath (architects: Farrell and Grimshaw).

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