Joints in the garage - what benefit?

Hello,

we received a precast concrete garage. The garage was assembled on site. The concrete floor slab therefore consists of several elements. Between these elements are joints of about 2-3 cm in size. When asked, the supplier said these are not normally sealed. There was no reason given for this. However, they have had several inquiries from builders asking what this is about, so they would also seal them with silicone upon request.

No one could tell me what function the joints have. I think they are expansion joints. But whether they also have a purpose regarding water infiltration is unclear to me. Does anyone know? In principle, water can collect there now. But is that really a good thing?! I also wonder whether, conversely, soil could grow through from below... there are strip foundations and gravel under the garage.

Now the question arises: seal with silicone (which will certainly weather soon, look ugly, and is not made to last forever) or just leave it? Could disadvantages arise from either option? The garage is ventilated continuously anyway.

Anyone have experience with this or heard about it before?

Just post a photo

Best regards in brief

Here are 3 pieces. Hope you can recognize something

And? Would really appreciate a brief assessment.

Upon inquiry with the supplier, these are not normally grouted. There was no reason given for this. However, they already had several inquiries from builders on their desk asking what that was about, and therefore they would fill them with silicone upon request.

That is probably first place in "Germany seeks the dumbest answer." If the manufacturer can't even name a constructive reason, then who can?

And you can recognize bunglers by the fact that no matter if you ask them "four times seven" or the year of Mozart's death, their answer is always "silicone." It doesn't get much sillier. Neither silicone nor foam sealant are cure-alls, but some people like to use them that way.

Ask a good building materials dealer what they have in stock for concrete expansion joints. Expansion joints of about 2 cm or a bit more are made where concrete components meet components made of other materials. And/or at additions, to avoid immediately incorporating settlement cracks. Some of these joints are actually air gaps, but more often they are sealed or filled elastically.

But this is generally done rather in the case of "wall junction." If I understand correctly, this only concerns the floor here. What about the walls?

I suspect as a banal reason that the cables of the lifting gear for positioning the planks have this width, and they are not pushed together after laying.

Such joints do not make lasting sense there—unless the foundation strips underneath are also multi-part. Water percolation there would be fatal: Google how potholes in roads appear (exactly like that). Besides, a bit of oil sometimes runs there, which would also be undesirable.

The joints should be sealed watertight—exactly that, to which simple minds always shoot out the universal answer from the silicone dispenser. Your building materials dealer surely has better options.

Thank you for the answer. We have no visible joints on the walls. I cannot say how they were sealed because they were painted over.

In this specific case, it actually only concerns the floor. The foundation strips underneath were shaped like an H. There are 2 pieces.

So, what exactly would be the right material for sealing? Sand, for example? Which elastic compound would be the correct one?