Skip Sheathing Could Be Costing You Thousands in Energy Loss
- Roofing Solutions of CT
- Nov 19
- 3 min read
If you live in a home built before the 1990s—especially one that originally had cedar shakes—you might have skip sheathing hiding under your roof. Most people don’t know what skip sheathing is, but once you understand it, you’ll see it for what it really is:
Massive gaps in your roof structure that allow heat, money, and energy to escape—every single day.
And when your roof has aged shingles, cracks, or even just normal wear and tear, those gaps become literal channels for cold air, moisture, drafts, and heat loss, causing skyrocketing energy bills, insulation failure, attic condensation, mold, and premature roof deterioration.
Let’s break it down.
What Is Skip Sheathing?
Skip sheathing (also called spaced sheathing) is a roof system made up of wood planks installed with wide 4–6 inch gaps between them, instead of a solid plywood deck.
It looks like this:
📐 Board — Gap — Board — Gap — Board — Gap
These gaps were originally designed to help old cedar shake roofs breathe naturally. That worked fine back then.
But today?
Those gaps are the equivalent of leaving sections of your roof completely unsealed, uninsulated, and exposed to air leakage and energy loss.
Why Skip Sheathing Bleeds Energy (and Money)
When you heat your home in winter or cool it in summer, you’re paying to treat the air inside.But when you have skip sheathing—especially under aging shingles—that treated air escapes constantly.
Even worse, cold air floods in through those same gaps.
Real-World Estimated Costs
Annual Heating & Cooling Bill | Typical Energy Waste from Skip Sheathing | Annual Loss |
$3,500 | 15–20% loss | $525–$700 |
$4,500 | 15–20% loss | $675–$900 |
$6,000 | 15–20% loss | $900–$1,200 |
And this doesn't include costs from:
✔ Increased wear on HVAC systems✔ Ice dam damage✔ Attic condensation and mold remediation✔ Loss of roof lifespan due to moisture exposure
Long-term? Homeowners can easily lose $3,000–$6,000+ over a few years.
Why It Gets Even Worse When Shingles Are Cracked or Aged
Skip sheathing on its own is inefficient—but when cracked, cupped, or aging shingles sit on top of it, those gaps become wide open air escape points.
Think of it like this:
🏠 You have boards with gaps... covered by shingles with cracks... sitting over an attic with poor insulation.
That’s not just inefficient.
That’s a financial drain.
Every gust of wind, every cold night, every draft from the attic — is pulling money right out of your home.
How Skip Sheathing Affects More Than Just Energy Bills
It’s not just about money lost from heat and AC. Skip sheathing creates structural problems too—expensive ones.
Long-Term Consequences:
Problem | Average Repair Cost |
Attic mold remediation | $2,000–$6,000 |
Roof deck replacement | $3,000–$8,000 |
Rafter repair due to rot | $1,500–$4,000 |
Ice dam damage & interior leaks | $2,500–$10,000 |
Complete re-sheathing during roof replacement | $4,000–$9,000 |
Why Modern Roofs Can’t Be Installed Over Skip Sheathing
Skip sheathing is not compatible with modern roofing materials like asphalt shingles, metal, synthetic shake, solar panels, or high-performance roofing systems.
Most manufacturers and insurance companies will void your warranty if you install a new roof over it.
Why? Because:
🔹 Nails don’t hold properly🔹 Underlayment isn’t fully supported🔹 Shingles can crease, sag, or blow off🔹 Moisture has more access points🔹 Energy code & fire safety standards fail
What Should Homeowners Do?
Your Three Best Options:
1️⃣ Install Plywood Over Existing Skip SheathingMost cost-effective and best long-term solution.
2️⃣ Fully Remove and Replace Skip SheathingIdeal for homes with rot, mold, or insulation upgrades.
3️⃣ Keep Skip Sheathing Only if Installing True Cedar ShakesEven then, many contractors still add a solid deck for strength and efficiency.
Final Thought
Skip sheathing isn’t just old—it’s outdated, inefficient, and expensive to keep.It may have made sense in 1975, but today, it’s:
❌ Bleeding heat❌ Driving up bills❌ Inviting moisture & mold❌ Shortening roof lifespan❌ Compromising energy performance
And the worst part? Most homeowners don’t even know they have it.
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