The brick parapet wall is solid construction but the flat roof is built on timber and will settle over time, the asphalt will melt in the summer and go brittle in the winter, with the thermal movement the cracking occurs.
So after cleaning of the roof taped patches are applied to the cracks before the new roofing system is installed to the roof.
The other interesting factor to all of this is the color of the finished roofing materials GacoRoof has a white finish and reflects the sun’s heat stopping the old roof from melting
- Preparation before a new liquid flat roof (epdm-rubber-roofing.co.uk)
- Why choose a liquid flat roofing system for your new flat roof. (epdm-rubber-roofing.co.uk)