Flat Roof Lime Insulation: A Natural Approach to Cooling Concrete Roofs
Concrete flat roofs can become extremely hot in warm climates, transferring heat into the rooms below and making the top floor uncomfortable. This often increases dependence on fans, air conditioners and other energy-consuming cooling systems. At a private residence in Janakpur, Nepal, we explored a simple natural approach to reduce heat transfer from an existing concrete flat roof. Instead of replacing the roof or relying on synthetic insulation, the concrete surface was resurfaced with a lime-surkhi layer and finished with clay tiles, creating a protective, non-radiating layer above the concrete roof.
- Location:
- Janakpur, Nepal
- Project Type:
- Private
- Completion Date:
- 04/2021
- Client:
- Dr. Ram Kewal Shah
- Design & Features:
- Total Footprint Area:
- 950 sq ft. (42 sq.m).
- Total Footprint Area:
Community Impact
The roof treatment helped improve the thermal comfort of the top floor by reducing heat transfer from the exposed concrete roof. By making the indoor space more comfortable, the solution can reduce dependence on high-energy cooling appliances such as air conditioners and blowers. Combined with better airflow, the improved roof performance makes the top floor more comfortable and usable during hot weather.
Sustainable Benefits
The project uses locally available natural materials — lime, surkhi and clay tiles — as an alternative to synthetic or highly industrial insulation materials. Surkhi and clay tiles can be produced locally, which can help reduce transportation requirements. The flat roof lime insulation approach also demonstrates how traditional materials and techniques can be adapted to improve the performance of existing concrete buildings.
Construction Timeline & Team
The roof insulation work was completed in one week by a small team consisting of tile mason Pradip and Dhiraj Kr. Shah.
Clay Tiles Concrete Roof Insulation
Key Learnings from this project
- An existing concrete flat roof can be upgraded using a lime-surkhi layer and clay tiles.
- A lime-surkhi roof treatment can help reduce heat transfer through an exposed concrete roof.
- Clay tiles provide an additional protective layer against direct solar exposure.
- Locally available natural materials can be used to improve thermal comfort in existing buildings.
- Traditional materials can be adapted to address modern challenges such as overheating in concrete buildings.
- Improving an existing roof can be a practical alternative to complete roof replacement.
