A lot of discussion out there about how to Repair Gypcrete Underlayment. Here is the official Gypcrete Repair and/or Gypcrete Replacement site:

Go to http://floomike.net

Mouse over the Gypsum Underlayment tab and you will see a drop down menu

Click on Gypcrete Repair for the official repair instructions

Under the same Gypsum Underlayment tab

Click on Mixing Instructions

Then click on the Yield and Pricing tab to determine how many bags you need

Then order the product from “floormike” by calling 1-800-247-5266 ext. 104