Can I use the same grout and sealer indoors as well as outdoors?

I am installing 600 x 600 x 10mm Brazilian Calibrated slate on the inside and 600 x 600 x 20-30mm B C slate pavers on an outside terrace.

I want the appearance to be seamless, so what is recommended for the grout product and dimensions? - the Granfix Charcoal Maxi Tile Grout (Flexible)

Floor/Wall has been recommended and ordered for the inside.

Also, do you recommend any sealant application to the exterior?

Hello Stephen

The same grout product can be used both indoors and outdoors slate tiles, of course with the outdoor pavers being potentially 3x the thickness, you will need to take this, as well as grout width into consideration when ordering quantities, if you need any help with this our sales team can advise.

With respect to sealing outdoors you can use the same mattstone or colour intensifier as you would indoors, both will leave a matt finish.