There are various slab systems in reinforced concrete buildings, and these are slabs settling on beams or shear walls and operating in one or two ways, one- or two-way ribbed (cassette) slabs, t-beam slabs, mushroom slabs, and pre-tensioned or post-tensioned slabs. Apart from these, the hollow core slabs are of distinct importance. Among these slabs that settle on the ground, there are ones with hollow cores and also ones with closed-cells. Such slabs are able to protect human health against the negative effects of water, moisture, and ground gases. In this study, the difference between Cobiax slabs (bubble deck slabs) and hollow core slabs settling on the ground was revealed. The principle of the systems in question is pouring of concrete on open-cell or closed-cell voided plastic components in the slab. Both in the open-cell module slab systems or in closed-cell module systems concreted by placing plates on them, advantages such as prevention of moisture through ground ventilation, reduction of building’s load, contribution to sound and heat insulation, and release to atmosphere of radon ground gases, which are hazardous on human health, are ensured.