The upgrading of existing housing by its very nature has traditionally attracted small-scale contractors. This also applies to housing maintenance. One reason why low-income settlements lack upgrading is that there is a disparity between the importance attached to new construction programmes vis-à-vis the upgrading of existing settlements. Almost invariably, any governmental programme of investment in low income shelter and infrastructure is linked to the construction of entirely new facilities. Another reason for the lack of response to upgrading is that it is a more challenging task than the straightforward construction of a new building.