Roof Deck Rot Signs: Identification, Causes, Repair Costs & Prevention in Ontario
What Is Roof Deck Rot?
Roof deck rot is the deterioration of plywood or OSB sheathing that forms the structural base your shingles attach to. This is a serious problem that needs prompt attention because once rot starts, it spreads fast.
Roof Deck Basics
Your roof deck is the foundation of everything up there. Think of it as the skeleton that holds your entire roofing system together. Most homes have either plywood or OSB panels spanning across the rafters, usually about half an inch to five-eighths thick. These panels create a solid surface where your shingles get nailed down, and they carry the weight of everything on your roof including snow loads and the occasional person walking around up there.
The material matters more than you might think. Plywood has been the traditional choice for decades because it handles moisture better and lasts longer. OSB is cheaper and more common in modern construction, but it acts like a sponge when it gets wet. If you have an older home built before the 1950s, you might find wooden planks instead of sheets, typically one-by-six or one-by-eight boards running across the rafters.
What Happens During Rot
The rot process starts innocently enough. Water finds its way through a roof leak and reaches the deck below. The wood absorbs that moisture like a paper towel. Once the wood stays damp for a while, fungal spores that are always floating around in the air land on the wet surface and start growing. These fungi need three things to thrive: moisture, warmth, and oxygen. Your attic provides all three.
As the fungi colonize the damp wood, they start breaking down the wood fibers themselves. This is where the real damage happens. The deck begins losing its strength and structural integrity, turning from solid lumber into something more like wet cardboard.
The timeline for this destruction varies based on how wet things get and how long they stay that way. Within the first few weeks to months you'll see staining and discoloration on the underside of the deck. After six months to a year, the wood starts feeling soft when you press on it. Between one and three years of moisture exposure, you get significant deterioration and noticeable strength loss. Past three years, you're looking at severe rot with a real risk of structural failure.
Most deck rot is what's called wet rot, where fungus breaks down actively wet wood. Dry rot is actually a misnomer because it still needs moisture to get started, but once established it can spread into drier wood. Dry rot is more aggressive and harder to stop once it takes hold.
Signs of Roof Deck Rot
Finding deck rot early let's you repair it before the damage spreads and costs multiply. The sooner you catch it, the cheaper the fix.
Interior Signs (From Attic)
1. Water Stains on Deck Underside
Look for dark brown, yellow, or black staining on the underside of your plywood or OSB deck. These stains usually follow the path water takes as it runs down from the leak source. The pattern tells you where the water entered and where its going.
This is your early warning system. Stains mean water got in, even if you don't have rot yet. Find and fix that leak source right now before the wood starts breaking down.
2. Soft or Spongy Deck
Press on the deck underside with your finger or push it with a screwdriver handle. A normal, healthy deck feels solid and firm with no give at all. A rotted deck feels soft or spongy and actually gives under pressure like pushing on a wet sponge.
The degree of softness tells you how far the rot has progressed. A little softness means early rot. Significant sponginess means the decay is well established and spreading.
3. Visible Mold or Fungal Growth
Check for black, green, white, or brown patches growing on the deck underside. The texture can be fuzzy, slimy, or powdery depending on the type of mold. Any visible growth means moisture has been present long enough for biological organisms to colonize the wood.
Where you see mold, rot is likely developing underneath or nearby. Mold and rot fungi thrive in the same damp conditions, so they usually show up together.
4. Delamination or Swelling
Watch for OSB or plywood layers peeling apart at the edges, or sections where the deck has swollen thicker than normal. When moisture gets absorbed into these engineered wood products, the glue holding the layers together starts failing. The deck actually gets thicker as the layers separate and the wood fibers expand.
Once delamination starts, the structural integrity is already compromised. The deck can no longer hold nails properly and can't support loads the way it should.
5. Sagging Deck Sections
Look for areas where the deck visibly droops between rafters or shows an uneven surface. This means the rot has progressed far enough to reduce the decks structural strength to the point it can no longer support its own weight plus the roofing materials on top.
A sagging deck can fail under load whether that's someone walking on it or heavy snow accumulation. This is a high-urgency structural problem that needs immediate attention.
6. Penetrable with Screwdriver
Take a screwdriver and push it into any suspect area. Sound, healthy wood resists the screwdriver and won't let it penetrate easily. Rotted wood let's the screwdriver sink right in with minimal resistance, like pushing into cork or Styrofoam.
How deep the screwdriver goes tells you how severe the rot is. Surface penetration means early rot. If it sinks in an inch or more, you have significant decay that needs replacement.
Exterior Signs (From Roof Surface)
7. Sagging Roof Surface
When you look at your roof from the ground, you might notice dips or low spots in the roof line. This happens when the deck underneath has rotted and weakened to the point it can no longer support the shingles properly. The weight of the roofing materials plus gravity makes the compromised deck sink down.
These sags often show up near valleys, around chimneys, or in areas where you've had leaks before. Those are the spots that stay wet longest and rot first.
8. Soft Spots When Walking
If you walk on your roof and feel the surface give or feel spongy under your feet, that's rotted deck below. You might also hear cracking or creaking noises as the compromised wood flexes under your weight.
This is dangerous. There's a real risk of breaking through rotted deck and falling. Don't walk on areas where you suspect rot. Get off the roof and call a professional. This is how people get hurt.
9. Nails Pulling Through or Loose
When you see shingle nails starting to pull up or shingles getting loose, the deck underneath might be too rotted to hold fasteners anymore. As wood rots, it loses its ability to grip nails. They just pull right through like pushing a thumbtack into wet cardboard.
Loose shingles blow off easier in wind, which creates more openings for water to get in. The problem feeds itself and gets worse fast.
10. Rippling or Uneven Shingle Surface
Shingles should lie flat and smooth across your roof. If you see waves, bumps, or an uneven surface, that usually means the deck underneath is uneven from rot-related deterioration or swelling. As the deck absorbs moisture and starts breaking down, it warps and creates an irregular surface.
The rippling pattern often follows leak locations or water damage areas. The shingles are just showing you what's happening to the structure below them.
Interior Living Space Signs
11. Ceiling Stains or Discoloration
Brown, yellow, or dark stains on your ceiling mean water has passed through the rotted deck and made it all the way into your living space. By the time you see ceiling stains, there's likely significant deck rot directly above that spot.
The stain location tells you exactly where to look in the attic for the damaged deck. Don't ignore ceiling stains, they only get bigger.
12. Musty Odor
That earthy, musty, moldy smell in the rooms below your roof is often coming from mold and rot in the deck or attic space. The odor is caused by microbial volatile organic compounds released as fungi break down the wood.
This isn't just unpleasant, it can also indicate air quality issues that affect your health. If you smell it, you have a moisture problem that needs fixing.
13. Visible Mold on Ceiling
Black or green patches growing on your ceiling surface mean moisture from a leaking roof is promoting mold growth. If there's enough moisture to grow mold on your ceiling, there's definitely enough moisture to rot the deck above.
Visible ceiling mold often indicates deck rot is already happening in the attic space overhead. The two problems go hand in hand.
Causes of Deck Rot
Knowing what causes deck rot helps you prevent it from happening again after you fix it the first time.
1. Roof Leaks (Primary Cause)
Roof leaks are the number one reason decks rot. Water finds a way through your roof and soaks into the wood below.
The most common leak sources include failed shingles that have cracked, gone missing, or just deteriorated with age. Chimney flashing failure let's water pour in at the junction where your chimney meets the roof. Valley leaks happen when the metal flashing in roof valleys fails and allows water straight through. Ice dams back water up under your shingles during Ontario winters. And penetration leaks around vents, skylights, or pipes that weren't sealed properly create entry points for moisture.
The progression is straightforward and predictable. A leak starts, water reaches the deck, the wood absorbs that moisture, rot develops in the damp wood, and then it spreads outward from there. Stop the leak early and you prevent the whole chain of events.
2. Ice Dams
Ice dams deserve their own section because they're such a huge problem in Ontario. When your attic gets warm, it melts the snow sitting on your roof. That meltwater runs down until it hits the cold eaves where it refreezes and creates a dam of ice. More water backs up behind that dam and has nowhere to go except under your shingles.
This water then saturates the deck right at your roof edges. Ontario gets 30 to 50 freeze-thaw cycles every winter, which means this process happens over and over, dumping water onto your deck repeatedly. The result is deck rot concentrated right at the eaves and in the valleys where ice builds up worst.
3. Condensation
Here's one that surprises people. You can get deck rot without any roof leak at all. Warm, moist air from your living space rises and enters the attic through gaps and poor air sealing. When that humid air contacts the cold underside of your deck in winter, physics takes over. The moisture condenses into water droplets right on the wood.
Your deck absorbs this condensation the same way it absorbs leak water. Give it enough time and rot develops even though you never had a drop come through the roof.
Several things make condensation worse. Poor attic ventilation traps that moist air instead of letting it escape. Inadequate insulation means more warm air reaches the cold deck. Air leaks at ceiling penetrations like light fixtures and fans let humidity pour into the attic. And bathroom fans that dump directly into the attic instead of venting outside pump moisture right where you don't want it.
4. Poor Ventilation
Your attic needs to breathe. When ventilation is inadequate, it traps moisture in the attic space instead of letting it escape outside. This prevents the deck from drying out after it gets wet, whether from a leak or from condensation.
A humid attic environment promotes fungal growth. The deck stays damp long enough for rot fungi to colonize and start breaking down the wood. Good ventilation would carry that moisture away and keep things dry. Poor ventilation turns your attic into a greenhouse for rot.
5. Aging Roof Materials
Old roofing materials stop doing their job properly. Shingles that are 20 years or older become porous and let water seep through gradually. The underlayment beneath them deteriorates and loses its waterproofing ability. You end up with multiple small leaks throughout the roof that slowly saturate the deck.
The tricky part is you might not see obvious interior leaking. The water doesn't come through fast enough to drip on your ceiling, but it's still getting the deck wet enough to cause rot. By the time you notice a problem, there could be significant decay hiding up there.
6. Previous Water Damage Not Fully Dried
Sometimes people fix the leak but forget about the wet deck. The leak stops but the deck never fully dried out. That moisture stays trapped in the wood.
Rot can develop from this residual moisture even after you stopped the leak. The wood needs to get properly dried using fans, dehumidifiers, or improved ventilation. Otherwise you fix the leak and still get rot anyway.
7. Low-Quality Deck Materials
Not all deck materials handle moisture the same way. OSB is less water-resistant than plywood, absorbs moisture faster, and swells more when it gets wet. Lower-grade plywood is less durable and more susceptible to rot. And if you have original decking that's 40 or 50 years old, those aged materials are just more vulnerable no matter what they're made of.
Quality materials cost more upfront but last longer when moisture inevitably finds its way in.
8. Ponding Water (Flat Roofs)
Standing water on low-slope or flat roofs is a recipe for deck rot. That constant water exposure puts pressure on the roofing membrane 24/7. Eventually it finds a way through, saturates the deck below, and rot develops rapidly.
Flat roofs need proper drainage. If water ponds in low spots for more than 48 hours after rain, you have a design problem that will lead to rot.
9. Nail Holes and Penetrations
Every single nail in your roof creates a penetration through the deck. Normally the underlayment and shingles keep water from reaching those holes. But when those upper layers fail, water runs straight through the nail holes and into the wood around them.
Rot often starts in a ring around the nail penetrations and spreads outward from there. It's one more reason why the waterproofing layers above the deck matter so much.
How to Inspect for Rot
Catching rot early through regular inspection saves you money because repairs are way less expensive when the damage is still small.
DIY Attic Inspection
You can do a basic inspection yourself with just a few tools. Grab a bright flashlight or LED headlamp, a screwdriver for testing the wood, and your phone camera for documentation. A moisture meter is optional but really helpful and only costs $30 to $100.
Here's how to inspect your attic for deck rot:
- Safety first: Wear a dust mask, watch for exposed nails sticking through, and step only on rafters or joists never on the insulation or ceiling below
- Visual scan: Look for staining, discoloration, or mold on the deck underside
- Focus on vulnerable areas: Pay extra attention near valleys, chimneys, plumbing vents, and roof edges where leaks happen most
- Touch test: Press suspect areas with your hand. They should feel firm, not soft or spongy
- Screwdriver test: Gently push your screwdriver into questionable spots. Sound wood resists, rotted wood let's the screwdriver sink right in
- Moisture meter: Check moisture content in several spots. Over 20% indicates a problem, over 28% means rot is likely present
- Document findings: Take photos of any concerns so you can show a professional later
Watch for dark staining, white or black or green growth, visible mold, swollen or delaminated plywood, sagging sections, and soft or spongy areas. Any of these signs means you need a closer look.
Exterior Visual Inspection
You can also inspect from the ground using binoculars. Look for sagging roof lines or low spots and dips in the surface. Note any shingle irregularities or areas with missing shingles because those sometimes indicate deck issues underneath. You're not going to see rot from the ground, but you can spot the symptoms that suggest it's there.
Professional Inspection
A professional inspection goes way beyond what you can do yourself. Pros do a comprehensive attic inspection with moisture meter testing throughout the entire space. They use thermal imaging that detects moisture through temperature differences, which finds wet areas you can't see. They'll walk on the roof surface to identify soft spots, assess the extent and cause of any rot, and give you detailed recommendations for the repair scope.
This costs between $150 and $400 for a detailed inspection including moisture assessment. The value is that it identifies all affected areas so you don't get surprise costs during reroofing. Finding the rot before you commit to a project is worth every penny.
Inspection Timing
Do an annual proactive inspection in spring or fall. Check after any roof leak occurs. Get an assessment before reroofing so you know the deck condition before getting quotes. When buying a home, make sure the home inspection includes thorough attic and deck assessment. And anytime you see signs like ceiling stains, musty smell, or visible sagging, inspect immediately.
Repair vs. Replacement
The decision depends on how much rot you have, where it's located, and what shape the rest of your roof is in.
Spot Repair (Limited Rot)
A spot repair makes sense when the rot is localized to a small area under 20 square feet, the rest of your deck is sound, your roof isn't ready for replacement yet, and you've identified a clear leak source that's fixable.
The process is straightforward. Your roofer removes the shingles over the rotted area, cuts out the damaged deck section, installs a new plywood or OSB patch, replaces the underlayment, and reinstalls or replaces the shingles. Most importantly, they address the leak source so it doesn't happen again.
This runs between $300 and $1,000 for a small patch covering 10 to 30 square feet. The repair is permanent if you actually fix the leak source. Otherwise the rot just comes back.
Section Replacement (Moderate Rot)
Section replacement is the right call when rot affects a significant area between 20 and 100 square feet but stays concentrated in one section like a valley, near the chimney, or along an eave. The rest of your deck needs to be acceptable and your roof should have remaining life left in it.
The contractor removes shingles from the affected section and replaces all the damaged deck which might be 8 to 12 sheets of plywood. They install new underlayment and reroof that section.
Expect to pay $1,500 to $5,000 depending on the size and how hard the area is to access.
Complete Deck Replacement (Extensive Rot)
Full deck replacement becomes necessary when rot is widespread across multiple areas or affects more than 30% of your deck. It also makes sense when your roof is at the end of its life anyway, typically 15 to 25 years old. At that point it's better to replace everything at once than do piecemeal repairs. You get a comprehensive solution with a warranty covering the whole system.
The process involves a complete roof tearoff where they remove all damaged deck which could be the entire thing or most of it. They install new plywood or OSB throughout, put down new underlayment, and complete the reroofing.
This adds $2,000 to $6,000 to your roof replacement cost depending on how much deck needs replacing. The advantages are huge though. You get a comprehensive solution, a new warranty on your entire roof system, a 20 to 30 year lifespan, and no hidden rot lurking anywhere.
Decision Factors
Go with spot repair if your damage is very limited under 10 square feet, your roof is under 10 years old with good life remaining, you've clearly identified and fixed the leak source, or your budget is tight.
Choose section replacement if you have moderate damage between 20 and 100 square feet, your roof is 10 to 15 years old with 5 to 10 years left in it, and the damage stays concentrated in one repairable section.
Pick complete replacement if you have extensive rot covering 30% or more of the deck or scattered in multiple areas, your roof is 15 years or older and approaching the end of its life, you want a comprehensive long-term solution, or you're dealing with multiple problem areas.
Repair Costs in Ontario
Assessment Costs
A standard roof inspection runs $150 to $300. If you want moisture assessment included, expect $250 to $400. Thermal imaging inspection that identifies hidden moisture costs $400 to $600 but can find problems you can't see with the naked eye.
Deck Repair Costs
Small Spot Repair (Under 10 sq ft)
$300 - $600
Remove shingles, cut out and replace small rotted section, patch and reroof
Moderate Patch (10-30 sq ft)
$600 - $1,500
Larger repair area with multiple sheets of plywood and more extensive shingle replacement
Section Replacement (30-100 sq ft)
$1,500 - $4,000
Replace significant section with 4 to 12 plywood sheets, reroof section, and address leak source
Extensive Replacement (100-300 sq ft)
$3,000 - $8,000
Large area that may be 30 to 50% of your deck, approaching full replacement territory
Full Deck Replacement (Added to Reroof)
$2,000 - $6,000
Complete deck replacement during full reroofing project where entire deck gets replaced
Structural Repair (If Rafters Damaged)
$2,000 - $10,000+
When rot extends to rafters or joists and structural members need repair or replacement
Cost Factors
Several things push costs higher. The extent of rot is obvious, more area means higher cost. Roof pitch matters because steep roofs are more difficult and dangerous to work on. Roof height plays a role since two-story work costs more than one-story. Access difficulty, complexity of your roof design, structural damage beyond just the deck, need for mold remediation, and winter work all increase the price.
Complete Replacement Cost
If you're reroofing with full deck replacement on an average Ontario home, you're looking at $8,000 to $15,000 for the standard reroof plus another $2,000 to $6,000 for deck replacement. Total comes to $10,000 to $21,000.
Compare that to leaving the rotted deck in place. New shingles installed over bad deck have a short lifespan. The nails won't hold in rotted wood. Your warranty may be void. And you'll need deck repair within a few years plus new shingles again. You end up paying more in the long run.
Insurance Coverage
Insurance usually covers deck rot if it was caused by a sudden event like storm damage or an ice dam, you maintained your roof properly, and you report the damage promptly.
Insurance usually does NOT cover gradual deterioration from age, neglected maintenance, pre-existing conditions, or improper ventilation which is considered a homeowner responsibility. Document your maintenance and report problems quickly to improve your chances of coverage.
Preventing Deck Rot
Taking proactive steps prevents the costly deck deterioration that leads to big repair bills.
1. Address Leaks Promptly
Stop moisture at its source by fixing roof leaks the moment you discover them. Don't put off "small" leaks thinking they can wait. Those small leaks cause rot just as effectively as big ones, they just take a bit longer. A $200 repair today prevents a $3,000 deck replacement a few years down the road.
2. Proper Attic Ventilation
Your attic needs adequate ventilation to stay dry. The rule is one square foot of ventilation for every 150 square feet of attic floor. You need balanced intake through soffit vents and exhaust through ridge vents so air flows through properly. This allows moisture to escape instead of condensing on your deck.
Improving your ventilation costs $500 to $2,000. The benefit is preventing moisture-related rot and extending your roof life by years.
3. Adequate Insulation and Air Sealing
Prevent warm moist air from your living space from reaching the attic. Ontario homes need R-50 insulation minimum. Air seal all penetrations where lights, fans, and pipes go through your ceiling. Seal the attic access hatch properly. And make absolutely sure your bathroom and kitchen fans vent outside, not into the attic where they dump humidity right where you don't want it.
4. Ice Dam Prevention
This is critical for Ontario. Keep your attic cold through proper insulation and ventilation. A cold attic prevents snow from melting on your roof, which prevents ice dams from forming. Ice dams are a major cause of deck rot at the eaves, so stopping them at the source saves you from water damage.
5. Regular Roof Maintenance
Catching problems early is the whole game. Get an annual professional roof inspection. Replace damaged shingles as soon as you spot them. Keep your gutters clean so water drains properly. Trim tree branches that hang over your roof. Address minor issues before they become major failures.
This costs $150 to $400 annually but prevents thousands of dollars in rot repair down the line. Its the best money you can spend on your roof.
6. Annual Attic Inspection
Monitor your deck condition yourself by checking the attic after heavy rains. Look for new staining or moisture that wasn't there before. Catch early signs before rot has time to develop. Take photos so you can compare year to year and spot changes.
7. Quality Materials During Reroofing
When you replace your roof, use quality plywood instead of the cheapest OSB available. Install proper underlayment with ice and water shield at vulnerable areas like valleys and eaves. Use adequate nailing that meets code. And never reuse deteriorated deck just to save a few bucks, it will cost you more later.
8. Proper Roof Design
If you're building new or adding on, get the roof design right from the start. Use adequate pitch for proper drainage. Install proper flashing at all transitions. Design ventilation into the system instead of trying to add it later. Specify quality materials in your plans.
9. Address Moisture Sources
Control indoor humidity to reduce the moisture that ends up in your attic. Use bathroom exhaust fans every time you shower. Vent your dryer outside, never into the house or attic. Run the kitchen fan when you cook. If your basement is damp, use a dehumidifier to keep humidity levels down throughout the house.
Frequently Asked Questions
How do I know if my roof deck is rotted?
The best way to check is from your attic. Look for dark staining on the deck underside, soft or spongy areas when you press on them, easy screwdriver penetration when you push into the wood, visible mold or fungal growth, swollen or delaminated plywood, and sagging deck sections.
From above you might notice a sagging roof line, soft spots when walking on the roof, or loose shingles where nails are pulling out. If you see any of these signs, get a professional inspection to assess the extent of the damage.
How much does it cost to replace rotted roof deck in Ontario?
The cost depends on how much rot you have. A small patch under 10 square feet runs $300 to $600. A moderate section between 30 and 100 square feet costs $1,500 to $4,000. Extensive replacement hits $3,000 to $8,000. If you're doing a full deck replacement during a reroof, add $2,000 to $6,000 to the project cost.
Variables that affect price include roof pitch, height, access difficulty, and extent of damage. Get a professional assessment for an accurate estimate based on your specific situation.
Can you put new shingles over rotted deck?
No, this is an extremely bad idea. Nails won't hold in rotted wood so your shingles will blow off prematurely. The rot continues spreading underneath. You may void your shingle warranty. It creates a structural hazard. And your leak risk is immediate.
You must replace the rotted deck before reroofing. Reputable contractors won't install over obvious rot. If a contractor is willing to do this, find a different contractor.
What causes roof deck to rot?
The primary causes are roof leaks where water enters through failed shingles or flashing, ice dams that back water under shingles which is super common in Ontario, condensation from moisture in your home condensing on the cold deck, poor ventilation that traps moisture in the attic, and aging roofing materials that become porous over time.
Bottom line is simple. Moisture plus wood plus time equals rot. Prevention is all about keeping your deck dry.
How long does it take for roof deck to rot?
The timeline varies based on conditions. Within weeks to months you'll see staining begin. After 6 months to a year, softening starts. Between 1 and 3 years, significant rot develops. Past 3 years, you get severe deterioration.
How fast this happens depends on the amount of moisture, temperature, ventilation, and wood type. Constant wetness means faster rot. Intermittent wetting with drying periods slows things down. But any moisture will eventually cause rot if you don't address it.
Should I repair roof deck or replace entire roof?
This depends on your roof age and how much rot you have. Repair the deck if your roof is under 10 years old, you have limited rot under 20 square feet, the leak source is fixed, and the rest of your roof is sound.
Replace the whole roof if it's 15 years or older, you have extensive rot affecting 30% or more of the deck, there are multiple problem areas, or the shingles are approaching end of life anyway.
The reasoning is straightforward. If your roof needs replacement within 5 years and deck repair costs $2,000 or more, you're better off doing a comprehensive replacement once. Otherwise you pay twice, once for the deck and again for the roof in a few years.
Will homeowners insurance cover rotted roof deck?
Sometimes, and it depends on the cause. Insurance usually covers sudden damage from a storm, ice dam, or tree falling, assuming you maintained your roof properly and reported the damage promptly.
Insurance usually does NOT cover gradual deterioration from age, neglected maintenance, pre-existing conditions, or improper ventilation which they view as a homeowner responsibility.
The key is documentation. Document your maintenance, report problems promptly, and show you were a responsible homeowner. This increases your likelihood of approval.
Can rotted roof deck be repaired or must it be replaced?
It must be replaced. Rot cannot be fixed. The fungus destroys wood fibers permanently and rotted wood loses its structural integrity for good. No sealants or coatings can restore that strength. The only solution is to cut out the rotted sections and replace them with new plywood.
The size of replacement depends on the extent. Could be a small patch or the entire deck. But any rotted sections must be removed and replaced with sound wood.
How can I prevent roof deck rot?
Start by fixing roof leaks immediately when you find them. Make sure you have proper attic ventilation with balanced intake and exhaust. Get adequate insulation, R-50 minimum for Ontario. Air seal all attic penetrations. Prevent ice dams by keeping your attic cold. Do annual roof maintenance and inspections. Monitor your attic for moisture regularly. And use quality materials during reroofing.
The bottom line is keep your deck dry. Fix moisture sources and make sure things can dry out properly. Do that and you won't get rot.
Is roof deck rot a structural concern?
Yes, especially if it's extensive. Your deck provides structural support for your roofing system. When it rots, it loses strength. It may sag or fail under load from people walking or snow accumulation. In severe cases there's a risk of roof collapse, though that's rare. There's also a real risk of falling through the roof when walking on it.
Minor localized rot is a moderate concern that needs attention soon. Extensive rot or visible sagging is an urgent structural issue requiring immediate action.
Concerned About Roof Deck Rot?
Get professional inspection and assessment from experienced Ontario roofing contractors who can identify extent of damage and recommend appropriate repairs.
Thorough deck assessment. Honest repair recommendations. Quality deck replacement.