10 Signs Your Roof May Need To Be Replaced

A roof is your home’s first line of defense. But like any structure, it has a lifespan and knowing when to replace it can save you thousands in future repairs.

If you’re wondering how do you know if I need a new roof, this article outlines the key signs to watch for, so you can take action before major damage occurs.

1. Your roof is over 20 years old

Roofing materials don’t last forever. Asphalt shingles generally last 20–25 years, while flat roofing membranes such as elastomeric membrane, EPDM, or modified bitumen can range from 15 to 30 years depending on the product and maintenance.

Even if your roof looks intact, aging materials can lose their protective qualities. If your roof is nearing the end of its expected lifespan, a professional inspection is strongly recommended.

2. Visible signs of surface deterioration

Whether you have shingles or a membrane, visible damage on the roof surface is a red flag. Keep an eye out for:

Curling or cracked shingles
Missing shingles after storms
Ponding water on flat roofs (water that doesn’t drain within 48 hours)
Blisters or bubbles on membrane surfaces
Membrane cracking or lifting near flashing or seams

These signs indicate that the waterproofing integrity of your roof may be compromised.

3. Daylight coming through your attic

If you can see sunlight peeking through your attic ceiling, it means moisture can get in too. Gaps in the roof deck often signal rot, displaced materials, or failing seals—issues that must be addressed before mold and structural problems develop.

This applies to both shingle and flat roofing systems, especially when roof boards or insulation layers start to degrade.

4. Sagging roof sections

A sagging roof is a serious structural warning. Common causes include:

Water infiltration
Rotting underlayment or support structures
Overloading (especially on flat roofs with snow accumulation)

This condition is urgent and should be assessed by a roofing expert immediately to prevent collapse or major repair costs.

5. Debris in your gutters and drains

For sloped roofs, granules from aging shingles often accumulate in gutters. This reduces the UV protection and waterproof capacity of the shingles.

For flat roofs, blocked drains filled with dirt, leaves, and membrane particles can signal breakdown of surface materials. Poor drainage also increases the risk of water pooling and leakage.

6. Moss, mold, or algae growth

Biological growth isn’t just an aesthetic problem—it can destroy roofing materials over time. Moss retains moisture, while algae and mold spread under and between layers, weakening your roof’s structure.

On shingle roofs: You may notice green patches or dark streaks.
On flat roofs: Look for moss clusters along seams and in pooling areas.

Avoid pressure washing. It’s often too aggressive and can shorten your roof’s life.

7. Increasing energy bills

If your energy bills are climbing and you can’t explain why, your roof might be the culprit. Poor insulation, air leaks, and failing vapor barriers on flat or sloped roofs allow heat to escape in winter and overheat your home in summer.

This inefficiency not only costs you more but also accelerates the deterioration of the roofing structure due to moisture build-up and thermal stress.

8. Damaged or aging flashing and sealants

Flashing around chimneys, vents, drains, and skylights must remain watertight. Cracks, rust, or displacement are warning signs. On flat roofs, special attention should be paid to flashing at walls and parapets.

Outdated flashing systems made of tar or cement should be replaced with modern materials like metal or reinforced membranes for longer durability.

9. Frequent roof leaks

If you’re dealing with frequent leaks—especially after rain or snow—there’s likely a deeper issue. Some leaks may appear minor but mask broader failures in the roof assembly.

With shingle roofs, water can enter through missing shingles, exposed nails, or valleys.
With flat roofs, leaks may be harder to trace but often stem from membrane seams, penetrations, or drainage failures.

Chronic leaks are a clear sign that it’s time to consider a replacement instead of ongoing patchwork repairs.

10. You’re planning to sell your home

A roof in poor condition is a major turnoff for buyers and home inspectors. Replacing your roof before listing your home on the market can:

Boost your property value
Speed up the selling process
Prevent negotiation setbacks
Offer peace of mind to future owners

Whether you own a duplex with a flat membrane or a bungalow with shingles, a new roof is a strong selling point.

Trust Duro-Toit for your roofing needs

Your roof protects everything underneath it—your belongings, your home’s structure, and your family. Ignoring the signs of roof deterioration can lead to costly consequences. If you’ve asked yourself, “how do you know if I need a new roof?”, and some of the symptoms listed apply to your situation, it’s time to consult a professional roofer.

Contact Duro-Toit today to schedule a free roof inspection. We’ll help you determine whether a repair is enough—or if it’s time for a full replacement.