Most Suburb properties have cast iron rainwater gutters, pipes and plumbing stacks. You should keep these or, if necessary, replace them in the same material, using traditional, not bolted, joints. Always retain hopper heads with dates or ornamental features. A few houses have external lead pipes and ornamental gutters which should be kept. We would resist the use of UPVC plastic rainwater goods and untidy external plumbing stacks with multiple branches. Additional soil and waste pipes should be located internally if possible to avoid clutter on the outside of the building. This would also mean that less expensive materials can be used internally. Balanced flues should be sited in unobtrusive locations. Drawings must always include full information about external pipework.