Soffit, fascia and edge rot
This page covers the damage that does not announce itself. Ice dams and blocked gutters do their work at the very edge of the roof, out over the overhang, and the consequences appear slowly in timber that most people never look at closely.
The parts, and what each one does
The fascia is the vertical board running along the ends of the rafters at the eave. It carries the gutter. The soffit is the horizontal panel closing off the underside of the overhang between the fascia and the wall, and it is where a properly ventilated roof takes in its air. The drip edge is a strip of metal at the roof edge whose job is to make water drop into the gutter rather than curl back onto the timber.
When any of the three fails, water gets into the overhang and stays there.
How it goes wrong here
The Kalamazoo sequence is predictable. Ice builds at the eave through winter. The weight and the freezing pull the gutter out of level, or pull the spikes or hangers out of the fascia altogether. Once the gutter is out of line, rainwater runs behind it in summer instead of into it, straight down the face of the fascia and into the end grain of the rafter tails. Add a missing or badly set drip edge and water runs onto the timber even when the gutter is fine.
Wet timber in a climate with long damp shoulder seasons rots. It rots from the back, where nobody can see it, so the first visible sign is usually paint blistering or a gutter that has started to sag in the middle.
Why it matters more than it looks
It is an entry point. A soft or missing soffit panel is a hole into the roof space at exactly the height squirrels, birds and wasps prefer. Dealing with an occupied attic costs far more than replacing a board.
It breaks the ventilation. Soffit vents are the intake half of attic ventilation. Rotten, blocked or painted over soffits mean no intake, which means the attic does not stay cold, which means more ice dams. The problem feeds itself.
It spreads. Rot moves from the fascia into the rafter tails and the eave decking, and at that point the repair goes from a board to carpentry on the roof structure.
What the fix involves
Getting to the timber means lifting the lower courses of roofing at the eave, which is why this is sensibly done at the same time as a reroof if the roof is anywhere near due. Rotten fascia and soffit come off, damaged rafter tails and eave decking are cut back to sound wood, new drip edge goes in, the gutter is rehung to a proper fall, and the soffit is replaced with vented panel so intake actually works.
Doing it on its own is perfectly possible and sometimes necessary. Doing it with a reroof is cheaper and gets the ice and water membrane in at the same time.
One independent southwest Michigan roofing company takes requests from this site. Ice dams covers the cause, and tear off and reroof covers doing both together.
Questions people ask
- Is this not just a painting job?
Painting rotten fascia hides it for a season and traps moisture behind the paint. The reason the wood is wet is nearly always that water is getting behind the gutter or coming back up under the roof edge, so the fix has to address the drip edge, the gutter line and often the eave decking as well as the timber itself. That makes it a roofing job with carpentry in it.
- Why does this happen more on my north side?
Because that side gets less sun, so snow sits longer, ice takes longer to clear and the timber dries more slowly after every thaw. Persistent damp is what rots wood, and a north facing eave under a shaded lot in this county can spend months of the year never properly drying out.
- Do I have to fix it now?
The timber itself is not urgent. What is urgent is that a rotted soffit is an open door into the roof space. Squirrels, wasps and birds all use it, and once something is nesting in the attic the job gets considerably more expensive and unpleasant. It also lets warm moist air move in the wrong places, which feeds the ice dam cycle.