How long does a roof last, and when should you replace it?

The roof is one of the largest repairs in a home, so knowing its age and condition helps you plan and budget, whether you own or are about to buy.

The short version: lifespan depends on the material, climate, installation and ventilation. Inspect the roof regularly, repair small problems early and plan the replacement before leaks start.

What affects lifespan

• Material: asphalt shingles are the most common; metal, slate, cedar and tile are others and often last longer, at higher cost. Manufacturers' warranties and a roofer's assessment are the best guide for your roof.
• Climate: freeze-thaw cycles, heavy snow, hail and heat all wear a roof down.
• Installation: poor workmanship shortens its life.
• Ventilation and insulation: a hot attic can age shingles faster, and poor ventilation contributes to ice dams and moisture.
• Maintenance: clean gutters, remove debris and trim branches.

Signs of trouble

• Curling, cracked or missing shingles.
• Bald patches, with granules in the gutters.
• Stains on the ceiling, or water in the attic.
• Daylight showing through the roof boards.
• Sagging areas.
• Damaged flashing around chimneys, vents and valleys.
• Moss or algae growth.

How to check

Look from the ground with binoculars. In the attic, check for stains, damp insulation and daylight. Do not walk on a roof unless you are trained and equipped; hire a roofer or inspector.

Repair or replace

A small repair, such as a few shingles or flashing, can be inexpensive. If damage is widespread or the roof is near the end of its life, replacement is usually more cost-effective than repeated repairs.

Buying a home

Ask the age of the roof, whether there are records and warranties, and whether it has leaked. Insurers sometimes ask about roof age or condition, and may limit coverage for old roofs, so check with your broker.

Hiring a roofer

• Get at least three written quotes.
• Check licences, insurance and workers' compensation coverage where applicable.
• Ask about materials, ventilation, flashing and warranty.
• Do not pay the whole amount upfront.

Example

You are buying a house with a roof that is near the end of its life. Ask for a roofer's opinion and a quote, and use it to negotiate or to plan your budget.

Costs vary widely by region, size and material, so get quotes.