Soffit & Fascia

Start with fascia, because it is structural in a way people underestimate. It is fastened to the rafter tails or truss ends and it carries the full weight of the eavestrough plus whatever is in it — and in a Calgary February, what is in it can be a solid block of ice weighing far more than the trough itself. Fascia that has gone soft cannot hold a hanger, which is why sagging eavestrough and rotten fascia are effectively the same diagnosis.

Fascia also closes the end of the roof assembly, and together with the drip edge it controls where water leaves the roof. Without a proper drip edge, surface tension pulls runoff backwards around the roof edge and down the face of the fascia rather than into the trough — which is exactly the mechanism that rots it.

Soffit's job is airflow. A roof assembly in this climate needs the attic to stay near outdoor temperature so that snow on the roof does not melt, run down and refreeze at the cold eave. That requires continuous air movement: cool air entering at the soffit, warm moist air leaving at or near the ridge. The rule of thumb is that intake area should at least equal exhaust area, and in practice intake is almost always the side that is short.

Soffit is also the exclusion layer. An open eave is an invitation — house sparrows and starlings nest in it, wasps build in it, and squirrels and mice use it as a door into the attic. Properly installed soffit with intact venting keeps them out while letting air through, which perforated aluminum does and a piece of plywood does not.

Four causes, in roughly the order we find them.

Overflowing eavestrough is the most common. A trough clogged with leaves and needles does not spill neatly over the front lip — a good deal of the water goes over the back, between the trough and the fascia, and runs straight down the board. That happens every rainfall for years before anyone notices, and the wood is saturated long before it looks bad.

Missing or incorrectly installed drip edge is the second. Drip edge is a cheap piece of formed metal that projects the roof edge past the fascia and breaks surface tension so water drops into the trough instead of curling back. Older Calgary homes frequently never had one, and plenty of re-roofs have skipped it. Without it, the top edge of the fascia takes water on every rain.

Ice damming is the third and the most damaging. Water backing up behind an ice ridge at the eave saturates the sheathing, the sub-fascia and the fascia from above, cycles through freeze and thaw all winter, and produces rot in the one place that is hardest to see and most expensive to reach.

The fourth is simply age plus paint failure on wood fascia that has never been capped. Once the paint film breaks, wood in this climate takes on water through every wet cycle and dries out through every chinook, and it does not survive many rounds of that.

The practical consequence matters: by the time fascia is visibly rotten, the sub-fascia behind it and often the rafter tails are compromised too. That is why we open it up and quote what is actually there rather than pricing a wrap over rotten wood, which is a common and dishonest way to make a low number.

For fascia, our default is aluminum fascia capping over a sound wood sub-fascia. The wood carries the structural load; the aluminum takes the weather and never needs paint. Where the sub-fascia is rotten, it gets replaced first — capping over rot is the shortcut that makes a low quote and a short-lived eave.

Aluminum comes in a wide colour range and is formed on site to the actual profile of your eave, which matters on older homes where nothing is quite standard. It is also the material that lets us match fascia, soffit and eavestrough in one colour family so the whole eave line reads as a single detail.

For soffit, aluminum is the workhorse: perforated for venting, solid for areas that must not vent, rigid enough to span, and available in both narrow and wide panel profiles. Vinyl soffit is lighter and less expensive, comes in vented and solid, and is a reasonable choice on a garage or a sheltered elevation. On acreages and exposed sites we generally specify aluminum for the wind resistance.

Where a home's architecture calls for it — heritage character, or a Hardie exterior — we install HardieSoffit or a wood soffit properly detailed and finished, so the eave suits the building rather than defaulting to metal on a house that should not have it.

The critical specification in every case is actual open venting area, not the appearance of it. Perforated panel has a published net free vent area, and matching that against the attic's requirement is the difference between a soffit that ventilates and one that only looks like it does.

Replacing soffit without confirming the intake path is open is the most common way this work gets done badly, because the panel looks perfect from the ground while the attic is still suffocating.

The usual culprit is insulation. Over the decades attics get topped up, and blown-in cellulose or fibreglass migrates or is blown directly over the eave, plugging the gap between the top plate and the roof deck. Every soffit vent below is then venting into a wall of insulation. We check this from the attic side wherever access allows.

The fix is baffles — rigid channels installed between the rafters at the eave that hold the insulation back and keep an open air path from the soffit into the attic. They are inexpensive, they are permanent, and installing them is enormously easier while the soffit is off than at any other time.

The second common culprit is paint. On older homes with wood soffit, decades of repainting can seal perforated vents almost completely. And the third is the original build simply not having enough vent area, which was routine on houses built before ventilation requirements tightened.

The last thing we check is what else is terminating up there. Bathroom and kitchen exhaust fans venting into the attic rather than through the roof are extremely common in this housing stock, and they push warm, humid air directly into the space you are trying to keep cold and dry. It causes ceiling staining that looks exactly like a roof leak, damp insulation and frost on the underside of the sheathing. Redirecting them properly is a small job with a large effect.

Soffit, fascia, drip edge and eavestrough are four products that meet in a space of about twenty centimetres, and every one of them depends on the others being right. That is the argument for doing them together.

In practical terms: there is no point hanging new eavestrough on rotten fascia, no point replacing fascia while leaving the drip edge that rotted it, no point installing vented soffit while the attic intake stays blocked, and no point correcting ventilation at the eave while the exhaust at the ridge is inadequate. Each of those on its own is a partial fix that leaves the underlying mechanism running.

The cheapest moment to do the whole eave is during a roof replacement, when the roof edge is already open, the crew is already mobilized, the disposal bin is already on site, and drip edge is going on anyway. Adding soffit, fascia and eavestrough at that point costs a fraction of what the same work costs as its own mobilization.

The second-cheapest moment is during a re-side, when scaffolding or staging is already up and the trim detail is being reworked anyway.

If neither is happening, the eave still stands on its own as a job — and if you have sagging troughs, streaked fascia or ice building along the edge every February, it is a job worth doing before it becomes a sheathing and rafter-tail job instead.

Eave work in this region concentrates on older housing stock and on properties with heavy tree cover. The 1960s and 1970s bungalows across Acadia, Willow Park, Haysboro, Thorncliffe, Highwood and Bowness are the classic case: original wood fascia, painted wood soffit with vents largely sealed, no drip edge, and an attic that has been under-ventilated for fifty years.

Under mature trees — Elbow Park, Mount Royal, Renfrew, Britannia, older Bridgeland — the same buildings also get chronic eavestrough clogging, which accelerates every fascia problem there is.

We do eave work across every Calgary quadrant and out through Airdrie, Chestermere, Cochrane, Okotoks, High River, Langdon, Strathmore, Crossfield, Carstairs, Didsbury, Olds, Innisfail, Red Deer, Sylvan Lake, Canmore, Beiseker, Three Hills, Drumheller, Nanton and Diamond Valley.

On acreages the driver is different: wind exposure. A country home with no windbreak takes driven rain and snow directly into the eave, and a soffit panel that would sit quietly on a city lot for thirty years can work loose out there. We specify heavier gauge and tighter fastening accordingly, and we include the garage, shop and outbuildings in the same visit — because sending a crew forty-five minutes out to do only the house is inefficient for everyone.