Provided are installation devices and uses thereof for receiving and installing an adaptor body for sampling soil gas under a slab. The installation device includes a cylindrical body and an internal cavity. The cylindrical body has a length greater than a thickness of the slab, a first end configured to be placed adjacent a top of the slab, and a second end configured to be placed below a bottom of the slab. The internal cavity extends longitudinally through the cylindrical body from the first end to the second end, where the internal cavity has a first portion and a second portion. The first portion has a first diameter located at the first end of the cylindrical body and the second portion has a second diameter that is less than the first diameter. The internal cavity of the cylindrical body is configured to receive the adaptor body.