Akon will be walking on water if his super baller glass floor ever gets installed -- but the contractor says it ain't happening until he gets paid, and Akon's mom stops flaking out on the plans.
Durable Steel Structures filed a lien against Akon's Georgia mansion ... claiming it's owed $36,765 for work already done on the home. Both Akon and his mother are named on the lien.
The contractor tells TMZ he's done a lot of work to design a glass floor that will make it seem like you're walking above a coral reef. He says the plan is to have LED lights projecting the reef images below the glass. Can you say P-I-M-P?
Only problem -- the contractor claims once it came time to install the floor, Akon's mom couldn't make a decision about the lighting ... so now he's left holding the bag.
Mama Akon and son also had a problem with a contractor in 2012, who sued ... claiming he was owed $51,941 for work on the same house.
We contacted Akon's camp ... but no word back yet.