When Do You Have to Replace the Roof Deck? A Homeowner’s Guide to Delaminated, Rotten, or Damaged Wood
When most homeowners think about replacing their roof, they focus on shingles - color, style, price. But there’s a critical layer underneath the shingles that determines how long your new roof will actually last: The roof decking (also called sheathing).
Decking is the wooden surface that shingles are nailed to. If it’s solid and healthy, your new roof will perform exactly the way it should. If it’s not? Your roof can fail long before its time - and in some cases, your manufacturer warranty may not apply.
This is why understanding roof decking matters, and why some homeowners face unexpected costs once their old shingles come off.
At Beemer KangaRoof®, we believe in explaining the why behind every recommendation so you can make informed decisions - and avoid surprises.
What Is Roof Decking?
Roof decking is typically made from:
OSB
Plywood
Its job is to:
Provide a solid nailing surface
Support the roof structure
Anchor shingles so they stay on in storms
Create a flat, uniform surface for underlayment and shingles
If the decking is compromised, it doesn’t matter how good the shingles are - the roof won’t last.
Signs the Roof Deck Needs to Be Replaced
Not all deck damage is visible from the ground. In fact, most homeowners don’t know they have decking issues until the shingles are removed. Here’s what we look for during replacement:
1. Delaminated Wood
This is extremely common but rarely understood.
What is delamination?
Delamination happens when the layers of plywood separate from each other due to moisture, heat, or age. Instead of a solid board, the layers start to peel or bubble apart.
Why is delamination a problem?
Nails will not hold properly
The board becomes soft or uneven
Shingles won’t sit flat
Moisture intrusion becomes more likely
Most manufacturers void shingle warranties if the decking doesn’t meet their specs
If the board looks swollen, rippled, or layered like a biscuit pulling apart - that’s delamination, and it must be replaced.
2. Rotten or Water-Soaked Wood
Water damage from past leaks, condensation, or poor ventilation can destroy decking.
Rotten boards:
Feel soft or spongy
May crumble when touched
Cannot hold a fastener
Water-soaked boards:
Stay damp long after storms
Warp or bow
Grow mold
Lead to attic moisture problems
If the deck can’t dry out or support the roof load, replacement is required.
3. A Surface That Cannot Hold a Nail
This is the bottom-line test.
If we drive a nail into the wood and it:
Spins
Slides out
Fails to bite
Sinks straight through
Wobbles loose
…that board cannot support a roof system.
New shingles must be anchored into structurally sound wood. Anything less is a guaranteed failure point.
How Shingle Warranties Come Into Play
Most homeowners don’t realize this: Using the wrong decking, or damaged decking, can void your manufacturer warranty.
Shingle manufacturers often require:
A specific decking thickness
Approved materials (OSB or plywood, NOT particle board)
A solid, dry, nail-able surface
No delamination
No rot or moisture damage
Even if the shingles are installed perfectly, a roof built on bad wood won’t be warrantied.
This is why identifying decking issues early can save you thousands later.
The Part Homeowners Don’t Expect: Hidden Costs
At Beemer KangaRoof®, we work hard to stay ahead of potential decking issues. That’s why our inspections include something most roofers skip: We get inside your attic.
By inspecting the attic side of the roof deck, we can often spot:
Moisture staining
Mold indicators
Soft or sagging plywood
Nail pull-through
Ventilation problems that weaken wood
This helps us catch many issues before we ever remove shingles - giving you clearer expectations and reducing unexpected costs.
But here’s the reality: Even with the most thorough inspection possible, some decking problems simply can’t be seen until the shingles come off.
For example:
Delamination may be hidden inside plywood layers
Water damage can travel between boards
Boards may look solid from the attic but fail a nail test
Surface deterioration can be invisible until exposed to daylight
Because of this, decking replacement is one of the most common unexpected costs during a roof replacement.
We prepare every customer for this possibility - not to scare you, but to keep you informed. Our goal is for you to never feel blindsided and to understand exactly what we find and why we recommend replacing a board.
Does Insurance Cover Damaged Roof Decking?
We fight for it every single time, but here’s the truth: Most insurance carriers do NOT cover decking replacement unless the wood is damaged by a covered peril.
In practice, that means:
Rot? ❌ Not covered
Moisture saturation? ❌ Not covered
Delamination? ❌ Not covered
Age-related deterioration? ❌ Not covered
If a tree falls through your roof - covered.
If a hailstorm smashes your decking - covered.
But normal wear, age, or improper ventilation? Not covered.
Still - at Beemer KangaRoof - we will always:
✔ Document the damage
✔ Present the case to your carrier
✔ Fight for every board we can get covered
Even when insurance won’t budge, our job is to help you understand exactly what’s required and why.
Beemer KangaRoof’s Promise: We Only Replace Wood When You Truly Need It
We know how frustrating unexpected costs can feel - especially on a major project like a roof replacement.
That’s why we guarantee: We will never recommend new decking unless it’s absolutely necessary.
But we also won’t install a brand-new roof on top of dangerous, failing, or non-warrantable wood - because that puts your home at risk and wastes your investment.
When we find decking that can’t stay, we:
Show you photos
Explain the issue
Break down the cost
Make sure YOU understand why it matters
Give you options wherever possible
We treat your home like it’s our own.
Why Decking Decisions Can Save (or Cost) Thousands
When decking problems are caught early:
You prevent structural damage
Your shingles stay intact longer
Your warranty stays valid
You avoid interior leaks
Your roof life increases
You avoid having to re-do the job
Ignoring bad decking or covering it up is a gamble no homeowner should take.
Considering a Roof Replacement? Start With the Right Information.
If you’re planning a roof replacement or if you’ve been told you need new decking, we’re here to explain the truth, answer every question, and walk through all your options.
At Beemer KangaRoof®, we make sure:
✔ You understand what’s going on under your shingles
✔ You never pay for unnecessary wood
✔ You never move forward without knowing your options
✔ You receive full photo documentation of all decking issues
✔ You get the most out of your new roof - for years to come
