Can you use liquid nails or glue with Hardibacker?
No. Where Hardibacker underlayment is being installed over a code-complying subfloor for the attachment of tile, the underlayment is installed over a 3/32″-1/4″ thick bed of bonding mortar and then nailed down. “Liquid Nails” is not a bonding mortar. It is a structural adhesive generally used to bond the subfloor to the floor joists just prior to nailing. It creates a very solid joint between the surface of the floor joist and the subfloor and aids in reducing floor squeak. The properties of Liquid Nails are such that it is applied via a tube in the form of a bead-like caulking. It is not trowelable like a mortar and therefore results in high ridges with unsupported areas that can deflect under load, resulting in cracked tile. Where the Hardibacker underlayment is being installed directly to wood or metal framing, the use of a structural adhesive in addition to mechanical fastening can be used. However, the underlayment must be forced into the structural adhesive almost immediately upo
