Realistic expectations by substrate
| Substrate | North / east | South / west | Notes |
|---|---|---|---|
| Wood siding, well prepped | 7 – 10 years | 5 – 7 years | Prep quality is the whole variable |
| Cedar, maintained | 8 – 10 years | 6 – 8 years | Excellent surface if not allowed to go past due |
| Aluminum, properly primed | 10 – 15 years | 8 – 12 years | Needs chalk wash plus bonding primer |
| Fiber cement | 12 – 15 years | 10 – 12 years | Best repaint substrate available |
| LP SmartSide | 12 – 15 years | 10 – 12 years | Watch cut edges and bottom courses |
| Vinyl, painted | 8 – 10 years | 6 – 8 years | Same shade or lighter only |
| Deck floor (horizontal) | 2 – 3 years | 2 – 3 years | Horizontal surfaces are a different world |
Freeze-thaw is what actually ends a paint job here
Homeowners generally assume sun kills paint. Sun degrades it, certainly, and it is why the south wall fades first. But in Wisconsin the thing that removes paint from a house is water changing state.
Wood absorbs moisture through the fall. That moisture freezes, and freezing water expands. It thaws, absorbs a little more, and freezes again, dozens of times across a Madison winter. Ice functions as a crowbar at microscopic scale, working underneath the coating film and lifting it from the substrate.
This is why paint fails from behind rather than from the front, and why a coating can look perfectly intact in October and be lifting in sheets in April. It is also why prep and same-day priming of bare wood matter far more here than in a mild climate. Anything that lets water reach the substrate has started a countdown.
The five reasons a paint job fails early
- Painting over a damp substrate. The most common cause and the most invisible. A wall that reads dry to the touch after washing can still hold enough moisture to prevent adhesion.
- Skipping primer on bare wood, or priming days after exposure rather than the same day. Bare wood left out overnight in Wisconsin humidity is already a different surface.
- Pressure washing instead of soft washing. High pressure drives water up behind lap siding and into end grain, where it sits until winter turns it into a wedge.
- Inadequate scraping. Painting a sound coat on top of a failing one means the new coating is only as attached as the layer beneath it.
- Applying too late in the day in autumn. A film that has not set before the temperature drops has already been compromised, and nobody finds out for two years.
How to get the long end of the range
- Wash the house every one to two years, especially the north and east walls. It is the cheapest exterior maintenance there is and it directly extends coating life.
- Keep gutters working. Overflow running down a wall will destroy a coating faster than a decade of sun.
- Cut back plantings so siding gets airflow. Shrubs against a wall hold moisture against it constantly.
- Re-caulk failing joints as they appear rather than waiting for the next full repaint.
- Touch up impact damage promptly. Any breach is an entry point for water.
- Repaint the south and west elevations on their own shorter cycle rather than waiting for the whole house to need it.
How to tell it is time
Chalking is the first sign: rub a hand on the siding and if it comes away with pigment on it, the binder is breaking down. Chalking alone is a repaint conversation, not an emergency.
Fading and a loss of sheen follow. Then hairline cracking, then lifting edges, then bare wood. The moment to act is between chalking and lifting, because once bare wood is exposed, every rain event is doing damage and the scrape percentage climbs quickly.