Outdoor grouting : epoxy vs cement-based vs polyurethane ?

[Anthelix]

Hi !
I will be tiling a south-facing patio with porcelain on a concrete slab. Which grout should I use ? I will need light grey and brown grouts (two different tiles).

• Epoxy : will it resist to constant UV exposure or could it turn yellow ? Isn't it too hard to clean on structured outdoor tiles ? I can find Mapei Kerapoxy and Litokol Starlike Evo.
• Polyurethane : is it still a thing or was it just a fad ? This seems very difficult to find here... Maybe some Litokol Fillgood Evo on special order.
• Modified cement grout : will it be durable ? I was considering Mapei Ultracolor Plus. Is there a better choice ?

 

[Anthelix]

Only one vote (thank you !) and no answer ?
Come on, don't be shy. 😉

 

[davidjohnsir]

My vote goes to Epoxy grout.

 

[Anthelix]

My vote goes to Epoxy grout.

Thank you very much. 😃

Do you think there is a risk that light grey epoxy turn yellow in direct sunlight ?

Which grout will be the easiest to use on sandpaper-like outdoor tiles : Kerapoxy or Ultracolor Plus ?