A photo showing rot and mold under siding

Is Your Siding Past The Point Of No Return?
Rot and Mold From the inside out.

The other day, while working on a cedar-sided home, we came across something we see all too often—serious rot and decay hiding beneath the surface. In many areas, the deterioration was so severe that even the structural components of the home were compromised. That’s not just a cosmetic issue—it’s a major safety concern.

Even worse, the mold and mildew had penetrated so deeply that it had reached the insulation, creating a breeding ground for unhealthy air quality inside the home. It was shocking, but unfortunately, not surprising. We’ve seen this time and time again, especially on cedar-sided homes that haven’t been maintained well over the past 20-30 years or more.  So, why does this happen? And more importantly, what can homeowners do to prevent it?

 

Window mold on cedar
Visiable mold on the surface of your cedar siding likely means rot underneath.

The Most Common Causes of Cedar Siding Failure

Cedar is a beautiful, natural siding option that adds warmth and character to a home, but it requires regular upkeep to stand the test of time. When left unchecked, here are some of the main culprits that contribute to rot, decay, and mold growth beneath cedar siding:

  • Poorly Flashed Areas – Flashing is meant to direct water away from vulnerable parts of a home, but when it’s improperly installed or deteriorates over time, moisture seeps behind the siding and begins to cause damage.
  • Cracked or Insufficient Caulking – Caulking helps seal gaps and prevent water infiltration. However, if it cracks, shrinks, or wears away, water can work its way in and create the perfect environment for decay.
  • Unsealed Nail Heads – Every nail driven into cedar siding is a potential entry point for moisture. If the nail heads are not sealed properly, water can penetrate and cause hidden damage over time.
  • Neglected Maintenance – Cedar siding needs to be treated with a natural oil or water-based sealer every 3 to 5 years to maintain its protective properties and keep it from absorbing moisture. Without proper sealing, the wood becomes vulnerable to rot and degradation (source).
  • Lack of Proper Gutter Drainage – Rain gutters are essential in preventing water from running down the exterior walls of a home. When gutters are missing, clogged, or improperly installed, water cascades down the siding, increasing the risk of mold growth both outside and inside the home. If you see mold on the exterior of your home, there’s a good chance there’s a problem lurking beneath the siding.

Cedar Siding Requires Ongoing Maintenance

While many of these issues can impact a variety of siding materials, cedar is particularly susceptible to rot and moisture damage if not properly maintained. Homeowners who love the look of cedar need to understand that regular maintenance is critical.

Even in ideal conditions, cedar siding has a limited lifespan. Many planks need to be replaced after just 10-15 years, and even well-maintained cedar siding may only last 20-30 years, depending on the climate. If proper upkeep isn’t maintained, deterioration can set in even sooner, leading to costly structural repairs down the road.

What Homeowners Can Do

If you have cedar siding, regular inspections are a must. Look for signs of cracking, peeling, mold growth, or areas where water may be infiltrating. If you notice any soft spots, discoloration, or warping, it’s time to act. Re-sealing your siding every few years, ensuring gutters are in good condition, and addressing any caulking issues can help extend its lifespan.

However, if your home is older and showing signs of significant wear, it might be time to consider a siding replacement with a more durable, low-maintenance material. Options like fiber cement or engineered wood siding provide the classic look of cedar without the extensive upkeep requirements. 

Final Thoughts

Cedar siding is beautiful, but it demands regular care to keep your home protected. The hidden damage we’ve seen in the field serves as an important reminder that what you can’t see could be causing serious problems beneath the surface. Stay proactive with maintenance, and if you’re unsure about the condition of your siding, don’t wait—schedule an inspection to catch potential issues before they become major headaches.

If you’re concerned about your home’s siding and want expert guidance, contact All Craft Exteriors today. We’re here to help homeowners make informed decisions about siding, windows, gutters and doors. Your home is likely your biggest investment – we can help preserve it and add value.

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