We would like to pave our terrace with natural stone, porphyry and sandstone slabs are particularly popular.
What do I really need to look at and what natural stone would you recommend based on your experience?
Just as important as the frost resistance of patio slabs is the surface of the stone (slip resistance). Stones with polished surfaces should not be used, as they can cause slipping when wet.
The properties of porphyry are high compressive strength, abrasion resistance, insensitivity to acids, and long life.
Not all porphyry is frost resistant, depending on where it is mined.
Sandstone is generally frost resistant, but not resistant to de-icing salt.
Resistance, durability, and good thermal conductivity are additional properties.
However, sandstone is usually very susceptible to staining.
Also note the ability to keep natural stones clean. If you drop a drink or a greasy sausage slips off your plate, you'll have problems if you can't remove stubborn stains.
In my day, I decided to use concrete slabs for my patio. Because of their color, concrete patio slabs have a Mediterranean style and look like natural stones. Also, concrete patio slabs are much cheaper than natural stones.