Many local Authorities now incinerate their domestic refuse to reduce the demand for tipping space; nearly a million tonnes of residues from the process are currently being produced each year. This report, the fourth in a series on waste materials, gives the results of a recent programme of research to assess the potentialities of incinerated refuse for roadmaking. The investigation shows that most residues could be used as bulk fill in earthwork construction and some are suitable for use as granular sub-base. Use of the material in road construction could help alleviate problems of obtaining suitable materials which are scarce in urban areas.