Customary practices

Building a structure on the grave

Q: Please advise: 

The Qabrs of Ambiya عليهم السلام, Awliyaa of the past رحمهم الله تعالى etc. especially overseas are built upon. Is this something permitted in other mazahib? Is this something that should be rectified? 

Someone had seen this link as well and was inquiring if this is a website that is reliable.

https://islamqa.org/hanafi/qibla-hanafi/43790/is-it-permitted-to-build-…