Slurry Seal is the application of a sealing coat to prolong the life of the existing materials. We use this process on surfaces which are still structurally sound but showing signs of deterioration. It is designed to seal the existing surface to stop water penetration which can lead to failure of the surface which would then require full reconstruction to be needed. It is a maintenance operation in the same manner as regular painting of wooden window frames for example.
The material is laid in the form of a slurry which is bitumen based with various additives to assist adhesion and setting of the material, it also has a small sized aggregate component to provide surface texture and regulate small level differences. The initial appearance is very ‘black’ as you mention but this will soon tone down to a ‘grey’ colour similar to other surfaces, this is a gradual change as the material hardens and weathers during the next couple of months, the surface finish will also become somewhat smoother during this time. To prevent water ingress to the underlying surface we do try to cover the joints at front and back of the path which is why you are seeing a small ‘lip’ against the walls.
An information sheet which is distributed to residents explaining the process is attached as a pdf file for
Devon County Council carry out a substantial programme of footway sealing work each year and the benefit of this in delaying the need for reconstruction of footways is considerable. The appearance of the work carried out is as we would expect for a newly applied treatment, the work will be inspected after the initial settling down period and any defects found will be attended too by the contractor as part of their programme.