Is it okay to only change two tiles in the bathroom, and only paste tiles without waterproofing?

It is impossible to do waterproofing partially, it must be done all, on the wall, on the ground at the same time construction, before painting waterproof coating, the ground should be hard, flat, and at the same time to remove floating dust.

The bathroom is waterproof, and the surrounding walls need to be painted at a height of not less than 30 cm; If there is a shower, the height of the waterproof paint applied on the installation of the shower faucet and the adjacent wall should not be less than 150 cm, preferably about 180 cm. This prevents moisture from penetrating into other parts of the bathroom.

After the waterproofing is done, a closed water test should be done. It is to put the water on the floor of the bathroom, so that the ground is completely submerged in water about 3 4 cm, and set a fixed elevation (horizontal plane); After 24 hours, if the water level is below the set elevation, it means that there is a water seepage problem on the ground, that is, the waterproofing is not done well. In this way, it is necessary to re-do the waterproofing.

If the bathroom waterproof paint is brushed and tiled on it, it should be painted with cement-based waterproof materials. The cement-based waterproofing material can be bonded to the cement base layer, its adhesion is very good, and it will not shell after pasting the tile. Other (non-cementitious) waterproofing materials are prone to shelling, which can cause wall tiles to fall off.

In addition, it is recommended to find a plumber to test whether there is a leakage problem in your water pipes with a pressure test pump, if there is no leakage problem in the pipes, then it can be determined that the water extends from under the bathroom to the outside of the bathroom, and it means that the waterproof layer of the original bathroom no longer works.

I didn't understand, what you said about the ground leakage in the first two days refers to the waterproof leakage of the ground, right? And the leak is related to the pipes, so did you make repairs to the pipes? But in any case, the replacement of tiles must be waterproof, and JS can be used regardless of whether the membrane or JS was used before.

After waterproofing, a 24h water storage test should be done, and the water storage height is 20 30cm above the ground, and then subsidize the tile after confirming that there is no leakage. Because it is only the replacement of two tiles, the second water can be exempted, but you must be careful not to damage the newly made waterproof layer when subsidizing.

It is recommended to do a little better waterproofing.

There is a water-repellent agent that is like water, mixed with ordinary cement, and sold in small bottles.

In order to be safe, it is best to do waterproofing, because once the waterproof layer destroys the entire waterproof layer, it has no effect.

You can use mortar waterproofing agent, mixed with cement river sand, and then used for tiling

If you don't destroy the waterproof, you can do it, but if you destroy the waterproof, you must do waterproofing. After a long time, it will drip downstairs, which is more troublesome.