The windowsills of a house are often made of Natural Stone, this is because they are the most resistant materials on the market.
In fact, these elements, in addition to determining the aesthetic value of the building, must also be durable as they are constantly exposed to the elements.
The windowsill differs from the threshold due to the presence of the drip tray, but the material with which they are made still makes them both natural insulators.
The existing color varieties allow for a wide choice, so you can match them both indoors and outdoors.