Slide Brackets are used to float pex tubing under a wood floor between 16 inch and 24 inch on center joist. Generally, you want the pex 1 inch below the flow and you do not want the PEX tubing to touch the insulation below. You should use zip ties to ensure that the PEX tubing does not move. This is one of the quietiest way to install PEX pipe under the floor.