This project is about thermal insulation for horizontal rooftops through tiles manufactured with recycled crumb rubber from scrap tires that responds to socio-ecological problems caused by scrap tire piles, such as impacts to the ecosystem (fires/groundwater pollution…), health impacts (vectors/fires...) and excessive electricity consumption for air conditioning in rooms without insulation that lead to higher costs/fossil fuel consumption and greenhouse gas emissions. It is an active thermal rooftop insulation system that also filters/retains rainwater and increases the life of the water seal.

We define this product as an "active” insulation, that differs from ‘passive’ insulating materials which delay the heat flow through them, because the solar radiation incident on the surface of the porous and permeable tiles heats up the exposed surface of the tile. This heat is transferred by thermal conduction through the rubber granules which dissipates some of it to the surrounding air. Hot air decreases its density and through convection drags the heat upwards, cooling the granules it flows through creating a chimney effect. This causes a negative pressure which sucks air from the lower pores and is replaced by air flowing through the edges of the insulating surface through the lower channels, venting/cooling the roof surface. It can be also classified as a ventilated roof system, making the process of heat transfer through the conduction-radiation-convection system slower than 'passive' insulation.

The product consists of tiles that can be manufactured locally, with molds and crumb rubber bonded with an adhesive, forming a porous and permeable structure that generates the ‘active insulation’ character and the functionality as a 'ventilated roof'. It is installed by placing the prefabricated tiles on the previously waterproofed rooftop. Additional to the insulation effect, it will also protect the waterproofing seal from harmful UV rays and sudden temperature changes extending its lifetime. The tiles can be handled by one person and can be removed for repair or home relocation. The bottom has a geometry that allows airflow and good drainage of rainwater to avoid water stagnation.

Some of the main differences of this product with others from the insulation market are: 1. Its porous and permeable structure draws the hot air from the roof reducing energy requirements for cooling; 2. The crumb rubber comes from waste (scrap tires); 3. It reduces the waste/pollution problem that tire piles pose, such as fire emissions, rodents and mosquitoes; 4. The tiles can be easily removed for repairs or to move to another home (portability makes it especially suited for rented homes); 5. It reduces rainwater runoff because the tile pores reduce the flow rate and retains some of the water by surface tension, once the sun rises water is evaporated causing a cooling effect by evaporation.

To recap, this system aims to generate improved indoor conditions while solving health problems due to vectors, tire fires toxins and air pollution by greenhouse gas emissions, as well as to reduce the consumption of fossil fuels for electricity generation.