When something goes wrong with your roof, the first question you'll ask is: do I repair it, or do I replace the whole thing?
Sometimes a repair is genuinely the right call.
Sometimes a repair is an expensive band-aid that postpones a larger bill.
We give homeowners a straight answer on this. If a repair is all you need, that's what we'll tell you. If the roof is past the point where repairs make financial sense, we'll explain exactly why, with evidence.
The 30% Rule
The most useful heuristic in roofing:
If the estimated cost to repair your roof exceeds 30% of the cost of a full replacement, and your roof is more than 15 years old, replacement is almost always the more economical decision.
But why?
Because an aging roof rarely has just one failing component. Addressing one problem typically reveals others, and you can end up spending repair money repeatedly on a system that's at end of life.
Beyond the 30% threshold, repairs still make clear sense in some situations. The goal of this guide is to help you identify which category you're in.
When Repair Is the Right Call
Repair makes sense when:
- The damage is isolated: a few wind-blown shingles, a single failed pipe boot, a small section of deteriorated flashing around a skylight or chimney
- The roof is relatively young (under 15 years) and otherwise in good condition
- The underlying decking is sound: no soft spots, rot, or water damage beneath the affected area
- The shingles in the affected area are still pliable and can be properly integrated with new material
- The repair addresses the actual root cause of the problem, not just the visible symptom
We're always honest about repair viability. If we can do a repair that will legitimately last another 10+ years and the rest of the roof is in good shape, we'll recommend it. There's no benefit to us in replacing a roof that doesn't need replacing. Our reputation is built on giving homeowners accurate information.
When Replacement Is the Right Call
Replacement is the better decision when:
- The roof is 20+ years old and showing widespread signs of aging (granule loss, curling, widespread brittleness)
- Multiple components have failed or are approaching failure at the same time
- The decking has sustained water damage or rot that requires significant replacement
- Ice dam damage has compromised the eave area, fascia, and lower courses of shingles
- A hailstorm has caused widespread shingle damage across the majority of the roof surface
- The previous roof was installed over existing shingles (a 'roof-over'). These almost always need a full replacement to fix properly
In Calgary, hailstorm damage often appears to be isolated but extends across the full roof surface. Hail bruising is invisible from the ground; it requires a tactile inspection (pressing on the shingle to feel the fractured fibreglass matting beneath).
If your home was in the path of a significant storm, assume the damage is widespread until a professional inspection confirms otherwise.
Did you know? "When we're called for what a homeowner thinks is a small repair, we always inspect the full roof before quoting. We can't count the number of times we've found that the 'small leak' is actually a symptom of widespread shingle failure or significant decking rot. Getting to the root cause first saves everyone money." — ALR Lead Installer
The Hidden Cost of Repeated Repairs on an Aging Roof
This is where homeowners most often make an expensive mistake. A repair on a 20-year-old roof might fix the immediate problem, but it doesn't buy you another 20 years.
When that roof fails again in 2–3 years (which it will), you've paid for both the repair and the eventual replacement. The total cost exceeds what replacement would have cost initially.
A useful way to think about it: if your car needed a $3,000 engine repair and was worth $4,000, you probably wouldn't do the repair. Roof economics follow the same logic. When the value of remaining useful life is less than the cost of keeping the existing roof alive, replacement wins.
The Roof-Over Problem
We see this regularly on homes where a previous contractor sold a homeowner on a 'roof-over', basically laying new shingles directly over old ones to save on tear-off costs. It's a decision that looks like a savings at the time and becomes a serious problem later.
The issues:
- It adds thousands of pounds to the home's structure
- It buries the old shingles, which continue to trap heat and decay beneath the new layer
- It voids virtually every shingle manufacturer's warranty;
- It makes it impossible to inspect or repair the decking without a full tear-off.
At ALR, we don't do roof-overs.
The Insurance Consideration
If your roof was damaged in a storm, the repair-vs-replacement decision may be made for you by your insurance policy.
In Alberta, policies typically cover replacement when storm damage is widespread enough to warrant it. However, policies with Actual Cash Value (ACV) endorsements will depreciate the payout based on the roof's age, meaning a 15-year-old roof might yield a payout that covers 50–60% of replacement cost.
Understanding your policy before filing a claim helps set accurate expectations. ALR can work with adjusters to ensure the full scope of damage is documented.
Making the Decision: A Simple Framework
Run through these questions:
- How old is the roof? (Under 15 years: lean repair. Over 20 years: lean replacement.)
- Is the damage isolated or widespread? (Isolated: repair. Widespread: replacement.)
- Is the decking sound? (Sound: repair viable. Compromised: replacement required.)
- Does the repair cost exceed 30% of replacement cost? (Yes: replace. No: repair viable.)
- Has the roof been through hail damage? (If yes, get a full professional inspection before deciding.)
- Are you planning to sell in the next 2–3 years? (New roof almost always beats credit or price reduction at sale.)
