It's the silent epidemic of 1980s-90s Twin Cities homes: cedar siding that looked beautiful when it was installed is now rotting from the back side, often invisibly behind fresh paint. We find it on a third of the Apple Valley, Eagan, and Burnsville homes built between 1980 and 1995. Here's what every Twin Cities buyer needs to know.
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Free Instant Estimate →Why cedar siding fails on Twin Cities homes
Cedar itself is a great siding material — naturally rot-resistant heartwood, beautiful when finished, lasts 60+ years if installed correctly. The problem is HOW it was installed in the 1980s building boom.
Most 1980s and early 90s Twin Cities builders nailed cedar directly to building paper over OSB sheathing — without a drainage plane (the gap between siding and sheathing that lets bulk water drain out and lets wet siding dry). When water gets behind the siding (and it always does eventually), it has nowhere to go. The back of the cedar stays wet for weeks. Rot starts from the inside.
By the time you can see surface damage, the back side is often deeply compromised.
The 7 signs of cedar siding rot
1. Cupping or warping boards
Cedar that's getting wet repeatedly will cup (curl outward) or warp. Visible from the side at any wall.
2. Soft spots when probed
We use a non-destructive probe to test accessible siding. Soft spots indicate active rot.
3. Cracked or missing caulk at joints
Caulking degrades after 5-10 years. Failed caulking lets water behind every joint and butt seam.
4. Peeling paint, especially in horizontal patterns
Cedar that's wet from the back pushes paint off in characteristic horizontal patterns. Re-painting without addressing the moisture source just hides the rot temporarily.
5. Missing or improper flashing at windows, doors, trim
The places where rot starts most often. We check every window head flashing, door pan flashing, and trim intersection.
6. Damaged or missing kick-out flashing at roof-wall intersections
Where the roof meets a wall, kick-out flashing diverts water away from the siding. Missing kick-outs cause concentrated rot in characteristic locations.
7. Visible fungal growth or staining
Black or green stains often indicate prolonged moisture and possible mold growth behind the siding.
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Free Instant Estimate →What we do during inspection
- Walk all sides of the home looking for visual indicators
- Probe accessible siding sections at high-risk areas (corners, butt joints, near windows, at grade line)
- Inspect all flashing details at windows, doors, trim, roof-wall intersections
- Check caulking condition
- Look for evidence of past repairs or replacement (sometimes hiding bigger problems)
- Optional: Thermal imaging reveals hidden moisture behind intact-looking sections
- Document everything in your report with photos and severity rating
Repair vs. replace: what's the right move?
Spot repair (cosmetic to minor)
Individual board replacement, re-caulking, and touch-up paint. Typical cost: $500–$1,500. Buys you 5-10 years if the underlying water management is okay.
Section replacement
One or two walls re-sided when rot is localized. Often paired with re-flashing windows and corners. Typical cost: $3,000–$8,000.
Full re-side
When rot is widespread or sheathing damage is found, full re-side is the right play. Most Twin Cities buyers go with fiber cement (LP SmartSide or James Hardie) rather than reinstalling cedar — it lasts longer in MN climate and insurance carriers prefer it. Typical cost: $20,000–$45,000+ for a typical Apple Valley two-story.
The biggest hidden danger: sheathing rot
When water has been behind cedar siding for years, the OSB sheathing behind it can rot too. Once sheathing is compromised, you're looking at structural repair on top of siding replacement. Cost can climb to $50,000+ on a larger home.
This is why a thorough inspection matters. We can't tear off siding to check sheathing, but we can use thermal imaging, probe at access points (around outlets, vents, openings), and check inside the home for telltale signs of sheathing failure (interior wall sweating, soft drywall at exterior walls, musty odors).
Twin Cities cities and neighborhoods most affected
- Apple Valley — Greenleaf, Palomino Hills, Diamond Path 1980s-90s subdivisions
- Eagan — Wescott Hills, Lebanon Hills 1980s two-stories
- Burnsville — many 1985-1995 builds
- Lakeville — older sections (pre-2000)
- Plymouth, Maple Grove, Bloomington — broadly 1980s-90s construction
How to negotiate cedar siding findings
- Get repair estimates from 2 reputable Dakota County siding contractors
- Document the scope and cost in your inspection objection letter
- Ask for a credit (preferred) so you control the contractor and timeline
- For full re-side situations, expect $5K-$15K+ in negotiation room — sellers know the next buyer will find it too
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