How to Install a Pre Insulated PEX Pipe

If you are planning to use insulated PEX pipe in your installation, then you should be able to fit these fairly easily. The plastic of the PEX pipe is generally more flexible and adaptable than the traditional copper or galvanized pipe, and is less vulnerable to corrosion. However, fitting the insulating PEX pipe usually requires the assistance of a professional, as the tools must be fitted with specialist tools. If you are able to rent these tools from your local home improvement store, then you may be able to fit these yourself. You will need specialist and basic home improvement tools, and some spare hours in which to install the pipe.

Materials Needed

  • Chalk
  • Shovel
  • Lumber
  • Drill with drill bits
  • PEX pipes
  • PEX fittings
  • Crimping tool
  • Supply valves
  • Plumbers tape
  • Wrench
  • Hammer

Step 1 - Mark out a Route

If you are installing the pipes below a floor, then you probably already know where the pipes should be fitted, but if you are fitting the pipes underground, then you need to dig out a suitable hole. This is so that the pipes can be laid down, and you can then cover the floor with a later of timber, to keep the pipes free of frost. When placing inside a floorspace, you will need to position a piece of pipe, mark out where the drill holes should be made, and then continue for the rest of the room.

Step 2 - Laying the Pipe

Drill out the holes on either side of the pipe. These holes will need to hold onto the floor studs securely. Connect the pipes together, and lay them down on the floor. You should place the pipes carefully on the floor. Make sure that all of the pipes are connected together securely, and if you are turning the pipe back around itself, for example when laying a underfloor heating system, then check that the pipe is correctly connected to the joints.

Step 3 - Connect the Fittings

Take one of the threaded fittings, and place it in the end of the pipe. You will need to attach a crimping ring to the end, and then press down on the ring using a PEX crimping iron. This needs to be pressed down until your PEX is crimped completely. When you have done this for as many pipes as necessary, attach the supply valve to the crimped end of the pipe, and connect it by tightening it using the wrench. You may need to knock the valve onto the pipe before you fit it, which can be done with a mallet or (very carefully) with a hammer.

Step 4 - Connect to Water

Attach the other end of the PEX water pipe to the supply hose, and then crimp the hose connection to the pipe. You should then feed the hose up to the central water pipe, and secure it using a wrench. Run a little water along the hose, and check for any problems such as leaks.