CHENNAI: The Greater Chennai Corporation (GCC) has directed its engineers to mandatorily mill existing bituminous road surfaces before relaying roads wherever necessary, in a move to prevent road levels from rising with every successive layer of tar.

The circular, issued by the GCC Commissioner requires engineers to assess and record existing road levels, drainage conditions and the levels of adjoining properties before taking up relaying works. It also directs officials to strictly avoid raising road levels through repeated bituminous relaying and to maintain the approved finished road level.

Under the new instructions, engineers must inspect and document the existing pavement condition, road levels, camber, cross-fall, longitudinal profile, drainage and adjoining property levels before relaying. Milling must be carried out to the required depth, width and profile using suitable mechanical equipment. The milling depth should generally correspond to the thickness of the proposed new layer, so that the additional layer does not increase the approved road level.

Engineers must verify and record the depth and quantity of milling before relaying. The circular also requires the existing road camber and cross-fall to be assessed and corrected during milling to achieve the approved profile after the new surface is laid.

Mechanical brooming is mandatory to clean the milled surface. Where mechanical milling is not feasible, including along road edges, trees and manholes, the existing bituminous surface must be removed manually or using suitable equipment. Manhole covers, utility chambers, footpaths and drainage structures must also be properly aligned .

The development comes after Arappor Iyakkam raised concerns over roads being repeatedly laid over existing surfaces without milling, leaving houses lower than adjoining roads and vulnerable to rainwater and sewage entering their premises.

The circular addresses the procedure to be followed in future relaying works, but does not expressly order the lowering of existing roads that are already higher than adjoining houses. Nor does it specify the penalties sought by Arappor, including withholding contractor payments, blacklisting and departmental action. The organisation had also demanded compensation of up to Rs.40 lakh for affected households and an expert committee to recommend solutions for roads and homes already affected.