Disclosed herein is a concrete article comprising: a plurality of pores having an average pore diameter of less than 1 micron as measured using mercury intrusion porosimetry (MIP) with a pressure of less than 440 MPa and overall porosity of less than 15% measured using helium porosimetry, wherein the concrete article exhibits a gas permeability of 10.sup.17 to 10.sup.22 m2 as measured under steady-state conditions (with an upstream chamber pressure of 0.31 MPa and a downstream chamber pressure of less than 5 Pa) and is configured to substantially prevent a gas leak. Also disclosed are methods of making the same articles.

Provided are cementitious panel that include a swellable material within a core layer, a dense layer, and/or a sheet of facing material that make up a cementitious panel, as well as methods of manufacturing such cementitious panels that include a swellable material and methods of providing a moisture or water barrier in a cementitious panel.