Why Is My Roof Leaking? Common Causes for Saskatoon Homes

The shingles are the roof's first line of defence, and they wear out. Prairie sun bakes them all summer, wind lifts and creases them, and years of freeze-thaw leave them brittle enough to crack. Once a shingle is curled, split or blown off, the layer underneath is exposed and a leak becomes a matter of time.

Flashing is the metal that seals the joints where a roof meets something else, a chimney, a skylight, a plumbing stack or a wall. It is one of the most common leak points on any roof, especially on older homes in Caswell Hill and Nutana, because those joints move and the sealant behind them dries out and pulls away over the years.

A roof can have perfectly good shingles and still leak steadily through a length of tired flashing. It is also one of the trickier repairs to get right, since the new work has to shed water the way the original was meant to.

Where two roof planes come together they form a valley, and a valley carries far more water than the open field of the roof, all of it funnelled into one narrow channel. When the valley flashing or the shingles woven through it wear out, that concentrated flow finds the weak spot fast. Valleys also catch and hold snow and ice through a Saskatchewan winter, which adds to the strain right when the roof is least able to take it.

In winter the leak often has nothing to do with a hole. Heat escaping into the attic melts the snow on the roof, the meltwater runs down to the cold overhang and refreezes into a ridge of ice, and the water backing up behind that ridge gets pushed up under the shingles. That is an ice dam, and it is a classic prairie-winter leak.

Every pipe and vent that pokes through the roof is sealed with a rubber boot or a collar, and rubber does not last as long as the roof does. A Saskatchewan winter is hard on it.

Once a vent boot cracks, water runs straight down the pipe and into the ceiling below, often turning up as a stain in a bathroom or kitchen. It is a small part and an easy fix, but an easy one to miss if nobody thinks to check the penetrations.

Not every ceiling stain is a leak. In a cold Saskatoon winter, warm indoor air meeting a cold surface in the attic can condense and drip, and from below the result looks a lot like a roof leak, and a plumbing line in a wall or floor above can do the same thing.

Part of a proper inspection is ruling these out, because new shingles will not fix a condensation or plumbing problem. If you are looking at a stain and are not sure what it means, our guide on what a ceiling water stain is telling you goes through how to read it.

A stain won't point straight at the hole, but where it shows up still narrows the search a lot. These are the pairings we check first when a Saskatoon homeowner tells us where the water is coming through.

• Beside a chimney or fireplace

  Chimney flashing first, then the cap and the mortar at the top of the chimney. Brick soaks up water, so the wet patch often sits lower than where the water got in.

• A bathroom or kitchen ceiling

  These rooms usually sit under the plumbing stack and the exhaust vents, which makes a cracked vent boot the first suspect. A bath fan that dumps moist air into the attic instead of outside can drip in winter too.

• Along an outside wall, up by the ceiling

  In winter that usually means an ice dam at the eaves. The rest of the year we look at the lowest rows of shingles and the drip edge, and check if the eavestrough is backing up.

• Around a skylight

  Most often it's the flashing around the frame. Cold glass also collects condensation in winter, and that drip runs down the inside of the frame looking exactly like a leak.

• Small damp spots across a top-floor ceiling, only when it's cold

  That pattern points to attic frost or condensation, not a hole. Take a flashlight into the attic on a cold day and look for frost on the nail tips poking through the roof deck.

The same roof can leak for different reasons at different times of year. When yours showed up is one of the most useful things you can tell a roofer.

• Spring thaw

  Snow that sat on the roof all winter melts in a hurry, and ice dams let go of the water they were holding. Weak spots in valleys and flashing tend to show up now. A stain that appears in spring and dries out by June still needs a look before next winter.

• Summer storms

  Prairie hail bruises and cracks shingles, and strong wind lifts tabs and bends flashing. Wind-driven rain also comes in sideways, so a roof that stays dry in a straight-down rain can leak in a thunderstorm. Photograph a storm leak before anything gets fixed.

• Fall

  Leaves fill the eavestroughs, and the first hard freeze can lock that mess in place with ice. It's the last easy window to fix small problems before snow covers the roof.

• Winter

  Ice dams and attic frost are the big two, plus fine snow blown in through roof vents on a windy day. A lot of winter leaks only appear during a mild spell, once that ice and snow starts melting.

One leak on a young roof is usually a single, fixable fault, while a leak on a roof near the end of its life is often just the first, because the whole surface is wearing at once.

That is the point where a repair buys a season and a replacement may be the better value, a call we help homeowners weigh in the guide on repairing versus replacing a roof. Either way the fix starts with finding the actual source, which is what a roof repair visit and a free HAAG Certified inspection with photos are for.

The age of the house changes where we start looking. Put a new roof on an old house and the chimney and additions are still there, along with whatever repairs came before.

In older neighbourhoods like Caswell Hill and Nutana, the chimney and the joints around dormers and additions come first. Old patch jobs sealed with roofing tar dry out and crack, and some older houses have a second layer of shingles over the first, which can hide soft decking underneath.

Newer houses in areas like Evergreen and Brighton have fewer of those joints but often more roof lines and valleys. On a newer home the leak is more often at a vent boot or a flashing detail, and attic trouble is common too, like a bath fan duct that came loose or insulation pushed up against the soffit vents.

Stay off the roof, especially when it's wet or icy. You can learn a lot from the ground and from the attic, and it gives whoever inspects it a head start.

1. Walk around the house and look up, with binoculars if you have them. Note any missing, curled or lifted shingles, and flashing that's bent or pulling away.
2. Check the ground under the downspouts, since a lot of shingle grit there, on a roof that isn't new, means prairie sun and freeze-thaw are wearing the shingles down.
3. Watch the eavestroughs in a rain. Water spilling over the front edge, or thick icicles along the eaves in a Saskatchewan winter, point to a drainage or ice dam problem.
4. Go into the attic with a flashlight during or just after a rain. Look for dark stains on the underside of the roof deck, water trails down the rafters and damp or flattened insulation.
5. Turn the flashlight off and look for daylight around pipes and vents where they pass through the roof, since on newer homes in Evergreen and Brighton the leak is more often at a vent boot. If light gets through there, water can too.
6. Trace the edge of the ceiling stain in pencil and write the date beside it, and if it spreads past the line after the next rain or thaw, the leak is active.

Good records help us find a leak faster. If a storm caused it, your insurer will want to see them too, and our page on how a roof insurance claim works in Saskatoon covers what we document for the adjuster.

• The stain or drip inside, with a tape measure or a coin in the shot for scale.
• The same spot a day or two later, so you can show if it grew.
• Anything in the attic that's wet or stained.
• Damaged drywall and belongings, before you move or throw anything out.
• The roof from the ground: missing shingles, debris, dented vents or eavestroughs.
• A short note of the date and what the weather was doing when the water showed up.

Keep the originals on your phone with the dates on them. If you plan to claim it, ask your insurer before you throw out any damaged materials.

A good inspection answers these without you having to push. If a contractor can't show you where the water is getting in, keep asking.

• Where exactly is the water getting in, and can I see a photo of it?
• Is this one fault, or is the rest of the roof wearing the same way?
• Did the water reach the roof deck or the insulation, and does any of it need replacing?
• Is a repair enough here, or should we be talking about a new roof?
• What warranty comes with the work, and who stands behind it?

Our HAAG Certified inspections are free, and you get photos of what we find. Our Saskatoon roof repair page shows how a visit works. If water is coming in right now, go straight to emergency roof repair.