Insulate a loft cold water tank

Wrap your loft cold tank and pipework in insulation to stop freezing, while keeping vital gaps clear underneath and around fittings.

LT-01Check the tank and plan your sessionTake a torch up and look at the tank for cracks, rust or a loose lid before you start. Check the loft hatch and boards are safe to kneel on, and clear a path to the tank. Note where the inlet valve, overflow pipe and any electrical cables run, so you can work around them.

1 each · Torch or head torch

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1 each · Kneeling board (offcut of plywood)

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LT-02Pull loft insulation back from under the tankIf the loft floor has insulation, pull it away from directly underneath the tank in a circle roughly 300mm wider than the tank base. Warmth rising from the ceiling below is what stops the tank freezing from underneath, and loft insulation under it blocks that warmth. Wear a dust mask and gloves, as old loft insulation is itchy and dusty.

1 each · Dust mask

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1 pair · Work gloves

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LT-03Fit the tank insulation jacketBuy a jacket sized for your tank, or cut rigid insulation panels to fit around the sides. Wrap it snugly around the tank and secure with the ties or tape provided, leaving the lid free to lift for inspection. Leaving a cold water tank uninsulated so it can freeze or burst breaches the Water Supply (Water Fittings) Regulations 1999, which require pipes and tanks to be protected from frost.

RULES

1 each · Cold water tank insulation jacket

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1 pack · Cable ties

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KNOW THE RULES

The Water Supply (Water Fittings) Regulations 1999 require cold water tanks and pipes to be protected against freezing.

LT-04Insulate the pipework leading to and from the tankSlide foam pipe lagging over every pipe connected to the tank, especially the overflow pipe, which is the one most likely to freeze and cause a leak through the eaves. Cut lengths with a utility knife and push them together at the joints, then seal joints with foil or duct tape. Cover pipes right up to where they disappear into the loft floor or wall.

5 each · Foam pipe lagging (1m lengths)

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1 each · Utility knife

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1 roll · Foil or duct tape

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LT-05Cover the tank lid, but leave it accessibleRest a rigid insulation board on top of the tank lid rather than sealing it down, so you can still lift it off to check the ball valve and water level. Cut the board slightly smaller than the lid so it sits without overhanging the tank edges. Do not tape or fix the board permanently in place.

1 each · Rigid insulation board, cut to size

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LT-06Check ventilation and clearances before you finishMake sure insulation does not block any loft eaves vents, as blocking these can cause damp and condensation in the roof space. Check the ball valve arm can still move freely and the overflow pipe is not kinked or covered. Confirm no insulation is resting against light fittings or cables, which can be a fire risk.

LT-07Tidy up and close the loftGather offcuts, packaging and tools, and vacuum up any loose insulation dust from the boards. Double-check the tank lid is sitting square and the jacket has not slipped. Close the loft hatch fully to keep warm air from the house rising up and wasting heat.

1 each · Bin bags for offcuts

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