A roof fails in high wind from the edges inward. Wind does not lift a shingle off the middle of a slope; it catches an edge that is not sealed down, peels it back, and then takes the row above it. Almost everything that makes a roof wind-resistant is about the perimeter, the fasteners, and the first few feet of decking.
That is worth knowing before you choose a shingle, because homeowners tend to focus on the product and installers know the failure is usually in the details.
What the wind ratings actually mean
Shingles carry two wind ratings and they are not the same test.
ASTM D3161 puts a shingle in a wind tunnel at a fixed speed and looks for lift. Class F is the top grade at 110 mph. ASTM D7158 is the more demanding one: it models uplift the way wind actually behaves over a roof, and Class H covers up to 150 mph.
Most architectural shingles sold today carry Class F, D7158 Class H, or both. The rating is printed on the bundle wrapper, and it is reasonable to ask to see one before the crew starts.
Here is the part that matters. Both ratings assume the shingle is installed exactly as the manufacturer specifies. Change the nailing pattern and the rating no longer applies. That is not a technicality. The fasteners are what the rating was measuring.
Six nails, not four
Standard installation is four nails per shingle. The Insurance Institute for Business & Home Safety asks for six in high-wind locations, and manufacturers publish six-nail patterns for the same reason.
Two extra nails per shingle across a whole roof is a real cost in labour and a small one in materials. It is also the single cheapest thing you can do to change how the roof behaves in a storm, and it is the first thing a cut-price bid quietly drops.
Ask any bid you receive whether it is four-nail or six-nail. If the answer is vague, that tells you something.
Nails have to hit the deck, and hit it straight
An overdriven nail cuts through the shingle mat. An underdriven one leaves the head proud so the shingle above cannot lie flat. A nail angled sideways holds on one edge instead of two. A nail that misses the deck entirely between rafters holds nothing at all.
None of this is visible once the roof is finished. It is one of the better arguments for having someone on site during installation rather than only at the end, which is why Proliance keeps a Quality Control Supervisor on the job throughout rather than sending an inspector at handover.
The perimeter does most of the work
Wind pressure is highest at the eaves, rakes and ridges. Those are the edges and corners, and they are where uplift starts, so that is where the specification should be strongest.
Starter strip along the eaves and up the rakes matters more than almost anything else. A proper starter course has its own adhesive strip that bonds the first row down. Cutting up ordinary shingles to make a starter, which happens, leaves that first row relying on nothing but its own weight until the sun seals it, and it may not seal before the next storm.
Drip edge metal along the eaves and rakes stops wind getting under the first course and gives the starter something solid to bond against.
Ridge and hip caps take direct pressure from two directions at once. They need the manufacturer’s matched cap product and the specified nail placement, not cut three-tab shingles.
Sealing takes warmth, and Chicago does not always provide it
Asphalt shingles self-seal. The adhesive strip softens in sunlight and bonds the shingle to the one below it. Until that happens, the shingle is held by nails alone.
In warm weather this takes a few days. On a cold, overcast October week it can take considerably longer, and a roof installed in November may not fully seal until spring. That is a genuine Chicagoland problem, not a theoretical one.
The answer is hand-sealing: a spot of roofing cement under each tab on the courses most exposed to wind. Good crews do this as standard on late-season installs. It is worth asking whether yours will.
Hail and wind are different problems
A shingle can be excellent in wind and mediocre in hail, because the two tests measure different things. Wind ratings measure whether the shingle stays attached. Impact ratings measure whether it survives being hit.
IBHS publishes an Impact-Resistant Shingle Performance Rating based on firing manufactured hailstones at shingles under real-world conditions. Products rated Excellent or Good handle hail up to two inches across.
For Chicagoland, where both wind and hail arrive in the same storms, it is worth checking both numbers rather than assuming a premium shingle is strong in each.
What about metal
Standing-seam metal handles wind well because the fasteners are hidden in the seams rather than exposed on the surface, and because panels run the full length of the slope so there are far fewer edges for wind to catch.
It costs significantly more than asphalt and not every house suits it visually. But on an exposed site, or a low-slope section where shingles struggle anyway, it is worth pricing rather than dismissing.
The roof deck underneath
None of the above helps if the fasteners have nothing to bite into. Older decking that has been through two or three roofs may have enlarged nail holes, soft spots, or boards that have lost their grip on the rafters.
Deck condition can only be assessed once the old roof is off, which is why a replacement quote should say what happens if bad decking is found and what it costs per sheet. A quote that is silent on this is a quote that will produce a surprise.
Questions worth asking any bid
- Four-nail or six-nail pattern?
- What starter strip product, at eaves and rakes both?
- Drip edge included?
- Manufacturer’s matched ridge cap, or cut shingles?
- Hand-sealing on late-season installs?
- What is the price per sheet if decking needs replacing?
Any competent roofer will have quick answers. The answers also make bids comparable, which is otherwise difficult when every quote is laid out differently.
Get the roof looked at
Proliance inspects roofs across the Chicago metro at no cost and provides a written report. Our inspectors are HAAG certified. If your roof has been through a windstorm and you are not sure what it did, that report is the place to start. Call 800-613-4373.
