Class 3 vs Class 4 Shingles: What the Ratings Mean in Surrey
Class 3 vs Class 4 Shingles: What the Ratings Mean in Surrey
A Class 4 shingle passed a tougher impact test than a Class 3 shingle, and that is the whole difference. Both are impact-resistant asphalt shingles tested under the same standard, UL 2218, and Class 4 is the highest rating available. For a Surrey home, townhouse complex or small commercial building, the real question is not which number is bigger. It is whether the extra toughness suits your roof, your insurance and your budget.
Hey, it’s Harman here. We get this question from homeowners and strata councils across Surrey and the Lower Mainland, usually just before a reroof. Here is how I explain it on the driveway.
TL;DR
- Class 3 and Class 4 are results of the UL 2218 steel ball test. Class 3 uses a 1.75-inch ball, Class 4 a 2-inch ball.
- Class 4 is the top rating, and Canadian resilience guidance now uses it as the baseline hail goal for new construction.
- No rating makes a shingle hail-proof. Very large hail can still damage a Class 4 roof, and shingles weaken with age.
- Ask your insurer about discounts before you decide, and check the exact product name, because not every shingle in a line is impact-rated.
- On a Surrey reroof, installation quality, ventilation and moss control matter as much as the class on the bundle.
Table of Contents
- What Class 3 and Class 4 actually mean
- Is Timberline HDZ Class 3 or Class 4?
- What Class 4 shingles are made of
- Does a Class 4 rating guarantee no hail damage?
- What the extra protection is worth
- Why this matters in Surrey and Metro Vancouver
- How to choose: a short checklist
- Our perspective
- Getting your Surrey roof priced
- FAQ
- Sources
What Class 3 and Class 4 actually mean
Impact-resistant shingles are measured by simulating hail impacts, then recording and classifying the results. GAF Canada describes the outcome as a Class 3 or Class 4 ranking, with Class 4 the highest.
The test behind those numbers is UL 2218, nicknamed the steel ball test. Owens Corning explains that it was developed in the mid-1990s after catastrophic hailstorms, and that a Class 4 shingle must withstand a 2-inch steel ball dropped from 20 feet. That is a force that could crack a 4-inch concrete paver in half.
Here is how the two classes line up:
| Class 3 | Class 4 | |
|---|---|---|
| Steel ball diameter | 1.75 inches (44 mm) | 2 inches (50.8 mm) |
| Impact energy | 18.37 joules | 32.12 joules |
| Standing in the test | High-performance impact resistance | Highest rating |
| Typical use | Hail-exposed areas where a lower-cost option is wanted | Hail-prone areas, insurance discounts, longest-lasting protection |
The joule figures come from the ICLR Resilient Homes Task Force hail guidance, which puts the Class 4 test at 32.12 joules against 18.37 joules for Class 3. In plain terms, the Class 4 ball hits with roughly three-quarters more energy.
The ball sizes and the Class 3 and Class 4 labels are standard. What isn’t standard is the shingle itself. Each manufacturer builds its impact-rated products differently, which is why the name on the bundle matters more than the class alone.
Is Timberline HDZ Class 3 or Class 4?
People search this one a lot. The honest answer is to check the exact product. Manufacturers sell a standard architectural line and, separately, impact-resistant versions of their shingles. GAF Canada lists Class 3 and Class 4 ratings as options among its shingle lines, which tells you the rating belongs to specific products, not to a whole brand family.
So before you sign a quote, ask your roofer for the product’s full name and its current data sheet, and look for the UL 2218 class printed on it. If the quote just says “architectural shingles”, ask which line and which class. A good contractor will answer that in a minute.
What Class 4 shingles are made of
Impact-rated shingles are not simply thicker. Most rely on tougher, more flexible asphalt and better reinforcement, so the shingle bends and recovers instead of cracking.
A few examples from manufacturers’ own literature:
- CertainTeed’s NorthGate is SBS-modified, carries the Class 4 rating and, according to the manufacturer, can withstand hail at 90 mph. They also note it may qualify for insurance discounts.
- IKO’s Cambridge IR carries a UL 2218 and FM 4473 Class 4 rating, is available in Western Canada, and has an extra coating of SBS-modified asphalt for flexibility and tear resistance.
- IKO’s Crowne Slate is rated Class 4 against FM 4473, meets the CSA A123.5 Canadian product standard and is made of two full layers of shingle material laminated together.
The pattern is clear: modified asphalt, and often a heavier build. That matters for the next point.
Not every Class 4 shingle is built the same
The ICLR guidance recommends roof cover products that comply with UL 2218 or FM 4473 Class 4 impact resistance. It also specifically advises against scrim-backed impact-rated products in favour of polymer-modified asphalt shingles. If you are choosing for long-term resilience, the construction of the shingle belongs in the conversation, not just the rating.
Does a Class 4 rating guarantee no hail damage?
No, and any roofer who says otherwise is overselling. The ICLR guidance notes that extreme hailstorms with high wind and hail beyond about 1.5 to 2 inches in diameter can exceed the limits of asphalt shingles, even Class 4 ones. It also notes that asphalt shingles become more vulnerable as they age.
Testing backs up the idea that the rating is a floor, not a force field. In a 2014 study of 22 asphalt shingle products, the Insurance Institute for Business & Home Safety found that none passed more than Class 2 impacts without at least one double-impact location failing. Repeated hits on the same spot are harder on any shingle than a single clean strike.
What that means for you: a Class 4 shingle gives you a meaningfully better chance in a hailstorm, and a better result with moderate hail. It is a sensible upgrade, not a promise.
What the extra protection is worth
Calgary sits in one of Canada’s most hail-exposed areas, so its numbers are a useful upper bound. The City of Calgary’s climate-ready roofing guidance says Class 4 shingles add about 45% to the cost of a standard asphalt roof, reduce the chance of hail damage by 15 times, and pay for themselves in about five years on average. It cites savings of $3 for every $1 of added cost.
Those are Alberta figures, so treat them as a reference point for hail-heavy regions, not a Surrey forecast. The way to translate them to your property is with two local questions:
- What will your insurer do? Some insurers discount premiums for Class 4 roofs. Ask your broker or the strata’s insurance agent for the discount in writing, with the exact rating they require.
- How long will you own the building? The longer you hold it, the more a tougher roof can pay back.
The Insurance Institute of Canada reports that the ICLR and CHBA task force guidelines include information on potential insurance incentives for each hazard, laid out in a Good, Better, Best framework. That is worth knowing, because it suggests Class 4 will keep showing up in insurer conversations.
Why this matters in Surrey and Metro Vancouver
The task force that wrote the hail guidance was launched in January 2024, and field trials are running in Ontario, Alberta and British Columbia. So BC is part of the national conversation, and what is considered a baseline roof is moving toward Class 4.
On the ground in Surrey, our day-to-day work is shaped by long wet seasons, moss, wind-driven rain and aging roofs. Impact resistance is one more layer of protection, and the same tougher, more flexible modified asphalt that earns a Class 4 rating is a sensible choice when you are already investing in a new roof.
Where we see Class 4 make the most sense
- Strata townhouse complexes. One roofing decision covers dozens of owners, and a longer-lasting roof means fewer special levies. Our strata and multifamily roofing team plans these projects around the building’s whole lifecycle.
- Cedar-to-asphalt conversions. If you are already stripping an old shake roof, the incremental cost of choosing a higher-rated shingle is small compared with the tear-off itself. Our cedar conversion service is published at 12 to 18 C$ per sq. ft., one-off.
- Homes with large exposed roof faces. Open, unsheltered slopes take the most abuse in storms.
- Owners planning to stay 15 years or more. The longer the horizon, the better the case.
Where Class 3 can be enough
Class 3 is still a high-performance impact-resistant shingle. If your insurer doesn’t ask for Class 4, the building is sheltered by mature trees or neighbouring structures, or the budget is tight, a good Class 3 product installed properly is a perfectly reasonable choice. A well-installed Class 3 roof will beat a poorly installed Class 4 roof every time.
How to choose: a short checklist
Bring these to your roofer, strata council meeting or property manager review:
- Confirm the exact product and class. Get the product name and the UL 2218 or FM 4473 class from the manufacturer’s current data sheet.
- Ask about the shingle’s construction. Polymer-modified asphalt is what the ICLR guidance favours.
- Call your insurer. Ask if a Class 3 or Class 4 roof changes the premium or deductible, and get the answer in writing.
- Check the Canadian standard. Look for CSA A123.5 on the data sheet, as on the IKO Crowne Slate sheet above.
- Plan for the whole system. Underlayment, ventilation, flashing and drainage decide how a roof actually ages in our climate.
- Think about age. Shingles lose hail resistance as they get older, so a Class 4 roof is not a set-and-forget answer for 30 years.
- Keep the roof clean. Moss and debris shorten the life of any shingle, rated or not.
Our perspective
We install asphalt shingle roofs across Surrey, Burnaby, Coquitlam, Delta and the North Shore, and the choice between Class 3 and Class 4 rarely stands alone. It comes with a roof that has to drain, breathe and shed moss through a long wet season.
Our view is simple. If you are putting a new roof on, Class 4 is a smart thing to price out, because the standards are moving that way and the added protection is built into the shingle itself. Where hail exposure and insurance terms point to Class 3, we will say so, and we will install it with the same care.
What we care about most is that the product on the quote is the product on the roof, and that the install is done to the manufacturer’s specifications. A rating on paper only counts when the underlayment, flashing, ventilation and fastening are done right. That is where decades of local roofing work show up.
Harman
Getting your Surrey roof priced
If you are planning a reroof and want Class 3 and Class 4 options priced side by side, we can inspect the roof, check the decking and ventilation, and put both on one quote. We work with homeowners, strata councils and property managers across Surrey, Burnaby, Coquitlam, Delta, and the North and West Vancouver shores.
Start with our asphalt shingle roofing page, or book a residential roof inspection so you know the condition of your roof before you choose a class. Property managers can go straight to our commercial roofing services. For more on how shingles are installed here, read our asphalt shingle installation guide for Canadian homes.
FAQ
What is a Class 3 impact shingle?
A Class 3 shingle has passed the UL 2218 steel ball test with a 1.75-inch (44 mm) ball. The test impact carries 18.37 joules of energy. It is a high-performance impact-resistant shingle that sits one step below Class 4.
What is a Class 4 roofing shingle?
A Class 4 shingle has passed the same test with a 2-inch (50.8 mm) steel ball, at 32.12 joules. It is the highest impact rating in the standard. Many Class 4 products also use polymer-modified asphalt for added flexibility.
Is Class 4 worth the extra cost?
It depends on your hail exposure, your insurer and how long you will own the building. In hail-heavy Calgary, the city’s guidance puts the added cost at about 45% with a payback of roughly five years. Ask your insurer for any discount in writing, and have both options priced on the same quote.
Will a Class 4 roof survive any hailstorm?
No. Very large hail, above roughly 1.5 to 2 inches, combined with high wind can exceed what asphalt shingles handle, even at Class 4. Roof age also reduces resistance, so inspections remain worthwhile.
Is GAF Timberline HDZ Class 3 or Class 4?
The class belongs to a specific product, not a brand name. Ask for the full product name and its current data sheet, and look for the UL 2218 class printed on it before you accept a quote.
Sources
- Roof Shingles: Asphalt Roofing Shingles | GAF Canada
- Class 4, Impact-Resistant Roofing Shingles | Owens Corning
- Hail Resilience Measures for New Construction | ICLR Resilient Homes Task Force
- Relative Impact Resistance of Asphalt Shingles | IBHS
- Climate ready measures: Roofs | City of Calgary
- Roof Toughness 101 | CertainTeed Canada
- The Cambridge Collection | IKO
- Crowne Slate technical data sheet | IKO
- Resilient home construction measures | Insurance Institute of Canada
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