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    Lagging pipes, radiators and cylinders

    Summary: Learn how to lag pipes, insulate radiators and insulate water cylinders.

    There are several simple ways of insulating your home that will save you money on fuel bills. This is achieved by fitting a non-heat conducting cover to pipes, water cylinders and radiators. This practice and the material used to perform it, is called lagging.


    Lagging should not only be fitted to cold-water pipes in danger of freezing but also to any hot water pipes that are not producing heat to warm a room. Foam lagging tubes are available for a range of pipe diameters. The foam lagging tubes usually have a cut running along the length to facilitate fitting them onto the pipes. Some foam lagging tubes have a silver foil lining to reflect heat back into the pipe, but these are generally more expensive.

    • Simply push the tubing on to the pipes like a sleeve, securing the ends of the tube with cable ties or tape. Where the ends of two tubes need to be joined together on a straight length of pipe, you can either butt them together or make a mitre joint
    • Where pipes bend make several small v-shaped cuts in the tubing at the point where it corresponds to the bend in the pipe. This will allow the tube to follow the bend in the pipe without forming ridges. Secure the tube in place with tape.
    • Where pipes join together at a T-joint, cut the end of one piece of tubing to make a wedge-shape that will fit neatly into the reverse of the cut in the other piece of tube.

    Push the tubing on to the pipes like a sleeve and secure the ends with cable ties or tape.

    Cutting mall v-shaped cuts in the tubing stops ridges forming in the tubing around bends.

    Water cylinders

    If you do not have a pre-insulated water cylinder, you should insulate the cylinder with a cylinder jacket. A cylinder jacket comprises of a number of plastic segments containing mineral-fibre insulation.

    • Measure the height and circumference of your cylinder to determine the size of jacket to purchase.
    • Feed a piece of string through the eyelets in the top of each section of the jacket and tie the sections around the pipes at the top of the cylinder.
    • Ensure the immersion heater cable is on the outside of the insulating jacket. Arrange the sections around the cylinder so there are no gaps and secure with the straps provided, but don't over tighten.

    Arrange the sections around the cylinder so there are no gaps, ensuring that the immersion heater cable is on the outside.


    Radiators positioned against an outside wall can lose up to 25% of their heat to the wall behind it. This is a serious waste of energy and money. However, fitting a foil-faced expanded polystyrene lining behind the radiator can save up to half the heat which would otherwise be lost.

    Naturally the best time to do this is when you are decorating and have removed the radiators to paint or wallpaper behind them. Waiting to redecorate before carrying out this task is not always convenient. Fortunately, the foil-faced expanded polystyrene lining can be applied without removing the radiator.

    • Turn off the radiator and make a note of its measurements.
    • Cut the lining material just slightly smaller than the dimensions of the radiator.
    • Mark the position of the radiator's fixings onto the lining and cut slender slots for them to fit through.
    • Using either wallpaper paste or double-sided sticky pads fix the foil-faced lining behind the radiator.
    • Feed the foil-faced lining behind the radiator and over its fixings and smooth into place using a length of batten. Remember the foil must be facing the radiator to reflect the heat back into the room.
    • If using paste or adhesive, wait for it to set before switching the radiator back on.

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    Tools Needed
    • Craft knife
    Materials Needed
    • Foam lagging tubes
    • Cable ties
    • Cylinder jacket
    • Foil-faced expanded polystyrene lining
    • Wallpaper adhesive OR double-sided sticky pads
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