Should porcelain stoneware be applied with or without joints? What kind of joints should I use?

In order to prevent tiles from coming loose, the following joints should be used:

1 - Laying joints - regular space left between two tiles.

The minimum recommended joints are:
Natural Finish - 4 mm joint
Rectified, honed, polished, semi-polished finishes - 2 mm joint
The minimum recommended joints for outdoor coverings are 5 mm.
The grouting of the laying joints should be done diagonally to the joints.

2- Fractioning joints - subdividing the covering into smaller areas and relieving the tension generated.

The maximum recommended areas for flooring and paving are:
Indoor: 32 m2, or when one of the sides is over 8 linear metres.
Outdoor: 25 m2, or when one of the sides is over 5 linear metres.
The maximum recommended areas for coverings are:
Indoor: 32 m2, or when one of the sides is over 8 metres long.
Outdoor: there should be horizontal fractioning every 3 metres, and vertical fractioning every 5 metres.

3 - Perimeter or corner joints - these are used when the plane changes, whether when walls and flooring meet or at corners in walls.

4 - Structural joints - regular space between two structures, envisaged in the project.

If brightly coloured or dark grouts are to be used, due to pigmentation, as a precautionary measure you should do a test with spare parts to check the performance of these.
The grouts in these colours require more careful and more frequent cleaning during laying.
When using products with rough or structured surfaces, you should apply a protector (e.g. Protector 060 from Weber) before regrouting.

Use grout with antifungal action to prevent or clean fungi that darken tile joints, (e.g. Weber.Color Premium) and, after drying, apply a waterproofing product (damp protection) - e.g. Weber.hydrofuge P, or any other water-based product.
Maintenance should be carried out every 4 years and this product should be applied again.

The joints should be cleaned when the grouting begins to harden. Do not use too much water when cleaning as this causes dispersal of the pigment and early discoloration of the grout.
After 24 hours, do a general clean-up using a dry or damp cloth.

In order to guarantee greater resistance of the grout to humidity, it should be waterproofed (e.g. Weber.hydrofuge B) 2 or 3 weeks after grouting.