Most winter roof faults begin months earlier. A tile that was slightly loose in September becomes a leak in December, a gutter half full of leaves in October overflows into the wall by January, and a ridge bedded on tired mortar waits for the first proper gale. Winter itself adds four stresses: water that freezes in porous materials, wind that finds every weak edge, snow that adds weight, and cold that turns warm household air into drips under the roof. Knowing which stress caused which sign makes it far easier to decide what is urgent and what can be fixed in spring.
Frost, and what it does to tiles and brickwork
Water expands as it freezes, and any material that soaks it up is at risk. Old clay tiles and some concrete tiles hold moisture in their surface, so a repeated cycle of wetting, freezing and thawing can flake the face off a tile or split it along a weak line. This is called spalling. A roof that looked sound in autumn can shed flakes into the gutter by February, and a cracked tile lets water reach the felt beneath.
Chimney stacks suffer in the same way. Mortar joints that have already lost their strength let water in, the water freezes, and each freeze pushes the brick faces and joints apart a little further. Pots can loosen and the flaunching (the sloped mortar collar that holds the pots in place) can crack and fall away. On older homes around Basingstoke with lime-mortared brickwork, a stack that has been neglected for years is a classic winter casualty. If you see crumbs of mortar or red dust in the gutter below, have the stack looked at.
Frost also attacks the roofline. Water trapped behind a badly seated fascia board or in a soffit that has begun to rot freezes and widens the gap. Check for flaking paint, soft timber and gaps where boards meet. Our page on finding and fixing a roof leak explains how we trace damage back to the source.
Wind: ridges, verges and loose tiles
Gales are the winter event most likely to produce an actual emergency. Wind loads a roof in two ways: it pushes on windward slopes and, more importantly, creates suction on the leeward side and at the edges. The ridge at the top, the verge (the sloping edge of a gable end) and the eaves are where that suction is strongest, which is why those are the places tiles go first.
Older ridges were bedded on mortar alone. Mortar cracks and loosens with age, and a ridge tile with a failing bed can lift or slide in a gust. Modern practice is different: BS 5534:2014 requires ridge, hip and verge components to be mechanically fixed, so mortar alone is not relied on. Dry-fix systems, which clip or screw the components down, are covered by BS 8612:2018. If your ridge dates from before this practice and the mortar is crumbling, a re-fix with mechanical fixings is a sensible winter repair. For the numbers behind the damage, see our answer on what wind speed damages a roof.
Wind also drives rain sideways, up under laps and past flashings that are fine in vertical rain. A roof that leaks only in a southwesterly storm points to a defect on that side. Our note on a roof that only leaks in wind covers how we find these. Afterwards, walk around the house and look for tiles on the ground, slipped tiles, lifted lead, bent flashings and anything lying in the gutters. Use binoculars from the garden, and do not go up on the roof.
For the aftermath of a big storm, read storm damage to roofs. If a branch or whole tree has come down, see tree fallen on roof.
Snow load, drifts and thaw
Snow is less common in this part of England than wind, but when it settles it matters. Fresh snow is light, but wet snow, or snow that has refrozen into a crust, is heavy. UK pitched roofs are built to carry it, but older roofs with sagging rafters, undersized timbers or a long-standing deflection can struggle. A roof that visibly dips, a ceiling that cracks, or doors upstairs that suddenly stick are signs of stress and deserve a prompt survey.
Flat roofs and the valleys of pitched roofs are the places where snow lingers and drifts. Snow melting on the warmer part of a roof can refreeze at the colder eaves, forming a ridge of ice that holds back thaw water behind it. Water pooled behind that dam can be forced up under the tiles or flashings. This is more common on roofs with poor insulation, where heat escaping from the loft melts the snow from underneath. It is also a good reason to fix loft insulation gaps.
Do not clear snow from a roof yourself. People fall, tiles crack under boot soles, and sliding snow can land on whoever is below. If snow is a worry, clear the ground beneath, wait for the thaw, and let a roofer inspect afterwards. The thaw is when most problems show: slipped tiles reveal themselves, gutters overflow and ceiling stains appear. A stain after a thaw is covered in our guide to water coming through the ceiling.
Gutters, ice and overflow
Gutters are where ordinary neglect meets winter weather. Leaves, moss and grit pile up in autumn, hold water and freeze solid in a cold snap. The ice adds weight, which can pull a gutter off its brackets or crack a joint, and a blocked outlet sends overflow down the wall or behind the fascia. Frozen water in a downpipe can split it as it expands.
The sign to watch for is water where it should not be: a dark streak down the outside wall, a damp patch on the inside of an external wall below a gutter, or a dripping stain at the eaves. If you can see a sagging section, or the gutter is spilling at a joint, clear what you can reach safely from the ground or a stable ladder, and book a repair rather than waiting for the next freeze. Roofline timbers that are already soft will not hold a new gutter, which is why a gutter job often turns into a fascia job.
Cold lofts, condensation and frozen pipes
Many winter ceiling stains are not leaks at all. Warm, humid air from showers, cooking and drying clothes rises into the loft, meets cold timber and the underside of the roof covering, and condenses. In a prolonged cold spell this drips onto the insulation and the ceiling, and it forms frost on nails and rafters that melts into drops when the temperature rises. Black spots of mould on timber are a common sign.
The fixes are about moving moisture out and keeping heat in. Extractor fans should vent outside rather than into the loft. Insulation should be thick enough to keep the loft cold but not packed over the eaves, where it blocks the airflow that carries damp out. Ventilation at the eaves and ridge needs to be clear. If you have a cold water tank in the loft, check that it and the pipes are lagged, because a burst pipe in a freezing loft creates exactly the kind of ceiling leak people blame on the roof. Our note on whether a roof leak can cause mould helps separate the two.
Flat roofs, lead and trees in winter
Flat roofs behave differently from pitched ones in the cold. A membrane that is already thin or lifting at the edges becomes brittle in a hard frost and can crack when walked on, so stay off a frozen flat roof. Water that sits in a hollow can freeze and thaw repeatedly, which stresses seams and the sealant around outlets. If a rear extension ceiling shows a stain after a thaw, suspect an upstand, an outlet or a low spot where water has been standing.
Lead flashings and valleys expand and contract with temperature. Old lead that has been dressed too tightly, or that is held by crumbling mortar, can split or lift over a few winters. A fresh gap at a chimney or wall is a common route for wind-driven rain. Lead repairs are possible all winter, though the work needs dry conditions.
Trees add their own trouble. Wet leaves lie in valleys and gutters, branches rub against tiles in a gale, and a laden evergreen can drop a limb in wet snow. Keep trees trimmed back from the roof, and have any overhanging branch dealt with before the stormy months. A tree that is protected or belongs to a neighbour needs a conversation, and sometimes permission, before it is cut.
A winter checklist, and what to leave to us
- After every gale, look at the roof from the ground for gaps, tile fragments and anything hanging from the edge.
- Keep gutters and downpipes clear, especially under overhanging trees.
- Check the loft for daylight, damp patches or wet insulation after heavy rain.
- Watch ceilings for new stains, particularly after a thaw.
- Look for moisture on the inside of chimney breasts and on walls below the roof edge.
- Do not climb onto a frosty, wet or snowy roof.
What can wait until spring is mostly cosmetic: moss, faded colour, and minor pointing wear. Anything that opens the roof to rain is different. A temporary repair can hold a damaged roof in winter, and our guide to temporary roof repairs explains what it can and cannot do. Permanent work on tile and flashing repairs can be done in most winter conditions, though some work, such as laying a flat roof membrane or bedding mortar, needs a dry, frost-free window.
When you contact us about a winter problem, we prioritise emergency calls, make a leaking roof safe first and then show you what we found on photographs of your own roof. Typical UK emergency call-out figures run from £150 to £350 before materials. Your fixed quote follows the survey. If you cannot tell whether a symptom is urgent, our guide on what counts as a roof emergency will help you sort it. You can reach us on 01256 213956 or by WhatsApp, and you can read about all our repair work on the emergency roof repairs in Basingstoke page.
