Danger in Sealing?

Danger in Sealing? Images

Danger in Sealing?

Danger in Sealing? Description

My outdoor patio is covered with Granite (http://tanbrown.org) and (http://maplered.com) is also the "roof" of the apartment below.

Could sealing have any bad effects, such as maybe trapping water underneath which might freeze or something?

My main concern is that there be no damage to the waterproofing for the apartment below.

Thanks for any suggestions or advice.