Gutters. Supports and fi xings to gutters should allow for thermal movement to take place and, in addition, expansion joints may be necessary. Spacing of expansion joints depends upon the fl exibility of the jointing material used, the method of jointing and supporting, and the co-effi cient of expansion of the material of which the gutter is made. Except where the methods of jointing and fi xing provide adequate allowance, very long lengths may have to be divided into suitable sections. The allowance for expansion may then be by means of a gap between sections, suitably weathered. Where the ends of gutters abut a structure (e.g. gutters fi xed between brick walls), a suitably weathered gap should be left between gutter end and structure. Structural and gutter expansion joints should coincide. Rainwater pipes. The type of jointing used for rainwater pipes should allow suffi cient movement for thermal expansion to take place without leakage, distortion and displacement of fi ttings. Particular care is necessary when rainwater pipes of long length are used. Thermal movement in upvc systems. The coeffi cient of expansion of upvc is 5 ×10−5 per deg.C giving a movement of about 0.5 mm per m length per 10 deg.C change in temperature. This thermal movement should be allowed for, and is accommodated for within the fi xing brackets to the fascia. Gutter and pipe fi ttings are designed to allow for expansion and contraction.