Roof and Chimney Flashing Repair in Edmonton

Seven details

The seven places flashing fails on an Edmonton roof

Almost every flashing repair in this city is one of these. Each does a different job and fails in a different way.

1. Step flashing

Individual L-shaped pieces woven into each shingle course where a roof runs up against a wall. Done properly it is invisible and lasts as long as the roof. Done as one long bent strip — still common on older Edmonton houses and on additions — it channels water behind the siding within a few winters. Step flashing is replaced, not resealed; it has to be woven in as the shingles go back on.

2. Counter flashing

The upper piece, let into a mortar joint or a reglet, that covers the top edge of step flashing so water cannot get behind it. On chimneys it is the part that works loose as the mortar weathers. Re-bedding counter flashing into a cut reglet with fresh mortar is a proper repair; a bead of caulk along the top edge is not.

3. Chimney flashing, and the cricket behind it

A chimney is a wall standing in the middle of a water path, so it needs flashing on four sides and, where it is wide, a chimney cricket — a small peaked saddle on the uphill side that splits snow and water around it. Chimneys wider than about 750 mm without a cricket collect a snow drift on the uphill face all winter, and that is where the rot starts.

4. Valley flashing

Valleys carry more water than any other part of the roof, and in Edmonton they also carry the snow load that slides off both slopes. Open valleys use exposed metal; closed valleys weave the shingles across. Both fail the same way: the membrane beneath wears through where the water runs fastest, and the fix is to open the valley, renew the ice-and-water membrane and re-lay it.

5. Drip edge

The formed metal at eaves and rakes that throws water clear of the fascia instead of letting it curl back underneath. Older houses here frequently have none. The symptom is rotted fascia and a stained soffit rather than an indoor leak — see soffit and fascia repair — and drip edge is normally renewed with the shingles rather than on its own.

6. Pipe boots and vent collars

The rubber collar around a plumbing stack is the shortest-lived component on the whole roof: ultraviolet light and freeze–thaw split it in ten to fifteen years while the shingles around it still have life left. It is a cheap, fast replacement and it is the single most common cause of a mystery leak in a bathroom ceiling. Skylights have their own version of this — a matched flashing kit woven into the shingle courses, covered on skylight repair.

7. Kick-out flashing

The small angled piece at the bottom of a roof-to-wall junction that kicks water out into the eavestrough instead of letting it run down inside the wall. It is missing on a large share of Edmonton houses, it costs almost nothing to add, and its absence is a slow soaking of the wall cavity that shows up years later as rot behind the siding rather than as a drip.

Why Edmonton kills flashing faster

Four local conditions do the damage. Freeze–thaw cycling works metal against masonry every time the temperature crosses zero — on Environment and Climate Change Canada’s 1991–2020 normals for Edmonton International Airport, at least 121 days a year cross it in both directions — and that opens sealed joints. A masonry chimney moves independently of the roof structure as it heats and cools, so a rigid joint between them is a joint that will crack. Snow load sits in valleys and against the uphill face of chimneys for months, and meltwater under it has time to find any gap. And hail dents soft metal — flashing, vent hoods, eavestroughs — which is both damage in its own right and the collateral evidence an adjuster uses to date a hailstorm.

Caulking is not a flashing repair

Sealant has a real job on a roof: it finishes a detail that is already mechanically correct. It cannot bridge a gap, replace a missing piece of metal or hold two materials that move in different directions. Roofing tar smeared over failed flashing hides the defect, holds water against the metal, and turns brittle in one Alberta winter — and it makes the eventual repair more expensive, because the tar has to come off before anything can be done properly.

This is also the repair least suited to a ladder and a Saturday. It sits where the roof is steepest and closest to a chimney, the diagnosis is the hard part, and the usual DIY outcome is a sealed symptom with the water still arriving somewhere new.

What the work includes

• Finding which detail is actually failing. Flashing leaks travel. The stain, the entry point and the failed piece of metal are usually three different places.
• New metal, not resealed old metal. Step, counter, valley, drip edge, pipe boot or kick-out replaced in the correct material and profile.
• Shingles lifted and re-laid properly. Flashing is woven into the courses, so the shingles around it come up and go back. This is why it is not a caulk job.
• Ice-and-water membrane where it belongs. Valleys and roof-to-wall junctions get self-adhering membrane beneath the metal. In this climate that layer does the real work.
• Masonry made good. Counter flashing bedded into a cut reglet and re-pointed, rather than surface-sealed against brick that is already spalling.
• The decking underneath checked. If the leak has been running a while, the sheathing under it is the real cost. We open it, photograph it and tell you what we find.