How are you all?

We just had our sandstone patio done. It's a wet finish with 4 inch concreate. It's not cheap. We want it to last long. I know water always cause damage. Sealing it seems to be a reasonable thing to do. We asked local Luck Stone Center. They said they do not recommend sealing sandstone patio because the seal will prevent moisture from coming out from the ground and cause more damage.

Is it true? How do we prevent winter freezing damage? Is there a sealer which is designed to do this job?

Thanks.

Weihan