Would a Biorock formed buiding be suitable for ocean floor research? Electrodeposition of dissolved minerals in seawater has been used to make coral reef repairs for quite some time. WOLF H. HILBERTZ patented the process and trademarked the name Biorock. I do not have access to IEEE, so I have only been able to read a small portion of this paper:
https://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=9015

https://doi.org/10.1109/OCEANS.2003.178283

The author of the article maintained that this process can build a seawall at a third of the cost of concrete, and it was suitable for building underwater constructions. I have only found references to using this process for repairing coral reefs, but none for construction purposes.

If the lower cost and material strength claims are valid, it would seem that this process would make it dramatically cheaper to build buildings at depth that could be used to make oceanic research facilities.

Is this a feasible approach to build ocean floor facilities for research or commercial purposes? Does the material formed have low enough porosity to be used as a building exterior wall?
I suspect the answer is no. The reason is that underwater constructions typically are supposed to be air- and water-tight, and to have strength enough to resist pressure differences. Biorock looks like it is naturally porous, so it would not be particularly good at holding water out. While the compression strength is like concrete, you really want to guarantee the solidity if you have humans in it. 

Basically, risk and uncertainty is a cost too. It is often worth paying extra to know what a structure can handle. So hence it might just be easier to use underwater concrete, where there is likely far more standardised quality. 

(Still, biorock is cool and will presumably in due time be well understood enough to compete with a lot of materials and methods.)