PPS 7 Addendum Residential Extensions and Alterations·Page 18·A37
Assessment factors beyond the 60/45 degree lines
The 60 and 45 degree lines are assessment tools used with other relevant factors; existing extension patterns in the area and proposed design features such as glazing are considered in evaluating overshadowing impact.
The guidance in Figure 1 is not however a rigid standard which must be met in every case. Rather it is an assessment tool which will be used in conjunction with other relevant factors in order to gauge the acceptability of proposals in terms of the overshadowing / loss of light impact upon neighbouring properties. Other relevant factors which will be considered in this assessment are set out below: (1) The existing form and type of extension prevalent in the area. For example, where the majority of dwellings in a terrace have already been extended in a similar way to the application proposal this matter will be balanced against any adverse impact on neighbouring properties. (2) The proposed design of the extension or alteration. For example, where a proposed extension incorporates significant glazing in the design, the impact on neighbouring properties may be acceptable in circumstances where alternatives might result in unacceptable overshadowing.
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