Winterising a Waterside Property Before Frost Arrives

Waterside Homes Face a Harder Winter

Living beside a river, canal, estuary or loch is a privilege for eleven months of the year. In the twelfth, that same water becomes the thing doing the damage. Air sitting over open water stays damp and cold, frost forms earlier and lingers longer, and wind funnelling along a valley or an open reach drives chill into every gap. Add the tide and the occasional flood warning, and a waterside property faces a winter quite unlike a house inland. None of the preparation is complicated, but the order you do it in matters, and a weekend of work now will save you weeks of drying out in January.

Protect the Pipes First

Burst pipes cause more winter insurance claims than anything else, and on a waterside property the risk is higher because pipework often runs through cold cellars, boathouses, outbuildings and unheated extensions. Water expands as it freezes and can split copper or plastic with surprising force; the leak usually shows up when the thaw begins.

• Lag every pipe in unheated spaces with foam sleeving of at least 15mm wall thickness, paying particular attention to elbows, joints and runs close to outside walls.
• Insulate the cold water tank and any exposed cistern in the loft, but leave the underside of the tank unlagged so warmth from the room below can still reach it.
• Fit an outside tap isolator and drain the tap down before the first hard frost. A frozen outside tap is a cracked wall and a soaked cavity.
• Find your stopcock now, label it and check that it turns. Everyone in the household should know where it is at eleven o'clock at night in January.
• If the property will be empty for more than a few days, either leave the heating on a low background setting — around 12 to 15°C — or drain the system down completely. Check your policy wording, as many insurers require one or the other after 30 days of absence.
• Condensate pipes from boilers are a classic winter failure. Insulate them and, if possible, increase the fall so water cannot pool and freeze.

Clear Gutters, Drains and Rainwater Goods

On the water, rain has nowhere to go but sideways. Blocked gutters and downpipes overflow into walls, into window reveals and down into foundations, and if that water then freezes and expands, the damage moves from cosmetic to structural.

• Clear leaves from gutters, hoppers and downpipes after the last of the autumn leaf fall, then check them again in January. Willow, alder and poplar beside water are relentless.
• Fit leaf guards or gutter mesh on stretches under trees, but keep them clean — a covered gutter full of silt is worse than an open one.
• Check that water butts, soakaways and surface drains are clear, and that downpipes discharge away from the building, ideally into a drain or a gravel-filled soakaway at least a metre from the wall.
• Empty water butts down to about a third if a hard frost is forecast, and lag any outdoor pipework feeding them.
• Look at ground levels around the base of the building. A gradient that falls away from the house, even by a few centimetres across a metre, is worth more than any amount of sealant.

Moorings, Pontoons and Boats

Mooring lines are the part of winterising most often left until the first gale, and by then it is too late. Cold makes synthetic rope stiff and easier to chafe, and a rising river can lift a mooring line from snug to slack, then snatch it tight again within hours.

• Slacken lines slightly to allow for higher winter river levels, and add spring lines so the boat cannot surge fore and aft.
• Double up on the lines that matter, using a mix of nylon, which stretches, and something with less give. Protect against chafe with rubber or plastic thimbles at every point where a line passes through a fairlead or over a pontoon edge.
• Check fenders, and check what they are attached to. A fender line tied to a stanchion base is a snapped stanchion base.
• If the boat stays in the water, keep the bilge dry, test the automatic bilge pump and its float switch, and make sure the batteries are charged. A flat battery in February means a boat sitting lower in the water.
• Drain and winterise the engine's raw water system or, better, have it done properly. Top up antifreeze in on-board freshwater and heating systems, and leave the fuel tank nearly full to limit condensation.
• Out of the water, check the trailer, cover and chocks. A cover that flaps in a January gale will rub paint off a hull in a fortnight.

Doors, Vents and the Fabric of the Building

Waterside houses breathe more than inland ones, and they ventilate badly if every gap is sealed. The aim is to keep water out while letting damp air escape.

• Check external doors, especially those facing the prevailing wind and rain. Replace tired seals and draught strips before the driving rain arrives.
• Keep trickle vents and air bricks clear. Blocking them to stay warm traps moisture, which leads to mould, and that costs more to fix than any heating bill.
• Clear high-level air bricks leading into a suspended floor or undercroft — flood water and leaves find them.
• Re-oil or treat external timber, decking and handrails while the weather is dry. Frost gets into untreated wood and opens up cracks.
• Check the roof for slipped tiles or slate, and clear moss from valleys. Beside open water, wind finds every weakness.

A Short Winter Checklist

Keep this where you will see it in October. Lag the pipes, drain the outside tap, clear the gutters, check the stopcock, slacken and double the mooring lines, charge the batteries, service the bilge pump, and run the heating on a low setting for a full day before you rely on it. Store a torch, spare fuses and the number of a good plumber somewhere you can find them in the dark. Do those things and winter on the water becomes what it should be: quiet, cold and utterly beautiful.