The Short Answer
Asphalt shingles seal with a thermal adhesive strip that only bonds after several warm, sunny days. Shingles installed in fall or winter may not seal until the following spring, and until then wind can lift them. Manufacturers require hand sealing (dabs of asphalt roofing cement under each shingle) for installs during prolonged cold, and GAF's warranty excludes wind damage when cold-weather shingles were not hand sealed.
Key Points
- The factory sealant strip is activated by sun and surface heat, not by the installer, so a cold roof can sit unsealed for months.
- GAF's 2026 limited warranty says shingles installed in fall or winter may not seal until the following spring.
- Hand sealing means small dabs of asphalt roofing cement placed under each shingle in the exact pattern the manufacturer specifies.
- Wind damage to shingles that never sealed, or that went on in cold weather without hand sealing, is excluded from GAF's wind warranty.
- A lifted tab that has not been creased can usually be sealed in place; a creased tab has to be replaced.
What the Sealant Strip Actually Does
Look at the back or face of a new shingle and you will see a line of dark asphalt adhesive, usually with a plastic release film near it so the shingles do not stick together in the bundle. Once the shingle is nailed down, that strip sits under the bottom edge of the next course up. When the sun heats the roof, the adhesive softens, flows a little and bonds the two courses into one sheet.
GAF's installation instructions for its Timberline HDZ family describe it plainly: a special thermal sealant that bonds the shingles together after installation when exposed to sun and warm temperatures. The nails hold the shingle on the roof. The seal is what keeps wind from getting under the edge and prying it up.
That distinction matters. Wind does not push a shingle off. It flows over the roof, creates suction at the edges, and tries to peel each course back from the bottom. A sealed shingle has no loose edge to grab. An unsealed one is held only by its nails, and the bottom few inches are free to flap.
Why Fall and Winter Installs Are the Problem
The adhesive needs surface heat, and a West Michigan roof loses that quickly after September. National Weather Service climate normals for Grand Rapids put the average daily high at about 61°F in October, 47°F in November, 36°F in December and 31°F in January. The normal high does not climb back above 50°F until April. Sun on dark shingles runs the surface warmer than the air, but short days, low sun angle and lake-effect cloud cover all work against it.
GAF says the result directly in its current shingle warranty: shingles installed in fall or winter may not seal until the following spring. CertainTeed's applicator manual says the same thing in different words, that sealing may be delayed if shingles are applied in cool weather. Neither is describing a defect. It is how self-sealing shingles behave.
So a roof finished in the second half of October can go through a whole Michigan winter, with its spring and fall wind events on either side, held on by nails alone. Most of those roofs come through fine. The ones that do not are usually the slopes facing the prevailing wind, the rakes and eaves where uplift is strongest, and any shingle that was nailed high or crooked.
How Long Shingles Take to Seal
There is no single number. GAF's warranty says self-sealing shingles must be exposed to warm, sunny conditions for several days before they completely seal. The Asphalt Roofing Manufacturers Association says sealing time varies with the slope of the roof, its orientation and how much sun and heat it gets. None of the manufacturers we reviewed publishes a minimum temperature or a fixed number of days, so be wary of anyone who quotes one as a rule.
- South and west slopes in full sun seal first, sometimes within days of a warm spell.
- North slopes and slopes shaded by trees or a taller part of the house can take weeks longer.
- Dust, pollen or grit on the sealant strip can keep it from bonding at all. GAF lists dirty sealant as a reason shingles may never seal.
- A shingle lifted by wind before it sealed may never seal on its own, because the strip is now holding dirt or the tab no longer lies flat.
- Raised or crooked nails hold the tab up off the strip. GAF's instructions say raised fasteners interfere with sealing.
Climate figures: NOAA NCEI 1991 to 2020 monthly normals for Grand Rapids Gerald R. Ford International Airport.
Unsealed, Lifted, Creased or Gone
Not every loose-looking shingle is damaged, and not every flat-looking shingle is sealed. The table below sorts out what you might see and what it usually means. Look from the ground with binoculars. Walking a cold roof to lift tabs is how shingles get broken, because asphalt is stiff and brittle in the cold, and it is how people get hurt.
The one to take seriously is the crease. A tab that the wind folded back far enough to leave a line across it has a broken mat at the fold. It may lie back down and look normal from the street, but it is no longer sealed and no longer strong, and it will not heal in the spring.
What the Manufacturers Say About Hand Sealing
Hand sealing is the fix the industry wrote for this problem. The installer puts small dabs of asphalt roofing cement under each shingle so it is glued down immediately, instead of waiting for the sun. The patterns are specific and differ by product, so the shingle wrapper or the manufacturer's current instructions always win over a general rule.
GAF Timberline HDZ family
Installation instructions
If shingles are applied during prolonged cold periods, or where airborne dust or sand is expected before sealing, they must be hand sealed. The pattern is 4 quarter-sized dabs of adhesive on the back of the shingle, 1 inch and 13 inches in from each side and 1 inch up from the bottom, with the shingle pressed firmly into it. The cement goes on as a thin layer under 1/8 inch thick, because excess can blister the shingle.
CertainTeed Landmark series
Shingle Applicator's Manual
Sealing may be delayed in cool weather and by airborne dust, and if any shingles have not sealed after a reasonable time, hand sealing may be necessary. On steep slopes CertainTeed calls for six nails and four 1 inch spots of roofing cement per full shingle, under each corner and about 12 to 13 inches in from each edge, and warns that excess cement can cause blistering.
Industry guidance
Asphalt Roofing Manufacturers Association
For better protection from blow-off in very cold weather, shingles can be hand sealed with an asphalt roofing cement or adhesive the shingle maker accepts. ARMA also recommends storing shingles warm before installation and avoiding bending, throwing or dropping bundles in the cold.
Ridge and hip caps
Often forgotten
Cap shingles are bent over the ridge and sit in the windiest line on the roof. CertainTeed's high-wind instructions for Landmark caps require hand sealing with specified adhesives to reach its Class F rating, and GAF's warranty points to the ridge cap instructions for maximum wind coverage. Ask about the caps as well as the field.
Patterns quoted from the GAF Timberline HDZ, UHDZ, AS II, CS and HDZ RS instruction sheet (RESTL622, 2023) and CertainTeed's Landmark chapter of its Shingle Applicator's Manual. Other product lines can differ.
Why Sealing Decides Your Wind Warranty
Shingle wind ratings assume a sealed shingle. ASTM D7158, the uplift test behind the Class D, G and H ratings printed on shingle wrappers, measures shingles applied per the manufacturer's instructions and sealed under defined conditions. A shingle that has not sealed yet is not the shingle that was tested, which is how a roof rated for very high winds can lose tabs in an ordinary fall storm.
The warranty language follows the same logic. GAF's Shingle and Accessory Limited Warranty, effective for GAF products installed after 1 January 2025, covers shingles that fail to seal or blow off after they should have sealed but did not because of a manufacturing defect. It then says failures to seal, blow-offs and wind damage before sealing occurs, or on shingles never exposed to adequate sun and surface temperature, come from the nature of self-sealing shingles and are not covered. Its exclusions list names the failure to hand seal shingles installed in cold weather.
In plain terms: if your roof went on in November without hand sealing and loses shingles in December, the manufacturer's wind warranty is unlikely to help. Whether your installer's own workmanship warranty covers it depends on that contractor's written terms, so read them, and ask before the job starts.
What Michigan's Residential Code Says About Wind Ratings and Hand Sealing
In Michigan, the shingle maker's cold-weather instructions are not just advice. The 2015 Michigan Residential Code, still the code in effect for houses, says in Section R905.1 that roof coverings shall be applied according to the code and the manufacturer's installation instructions, and Section R904.1 repeats it. When a wrapper or instruction sheet says to hand seal shingles installed in cold weather, the code makes that part of a compliant install. Section R905.2.6 adds a floor for nailing: the manufacturer's required number of fasteners, and never fewer than four per strip shingle.
The code also sets a minimum wind rating. Section R905.2.4.1 requires asphalt shingles to be tested to ASTM D7158 and labeled with the class Table R905.2.4.1 calls for at the design wind speed. Michigan's version of the climate table, Table R301.2(1), fills in a wind speed of 90 mph statewide. At that speed, read as either an ultimate or an allowable-stress figure, the table accepts D7158 Class D, G or H, or for shingles outside that standard, ASTM D3161 Class A, D or F. Most architectural shingles sold today are labeled well above that minimum, but every one of those classes assumes a sealed shingle.
Lakeshore homes are the exception to watch. A footnote to the shingle table says the D7158 calculations assume Exposure B or C and buildings 60 feet tall or less. Section R301.2.1.4 defines Exposure D as sites facing wind that crosses at least 5,000 feet of open water or unbroken ice, reaching 600 feet inland or 20 times the building height, whichever is greater. For a house on a Lake Michigan bluff, the code asks for additional calculations, and an unsealed fall install is even more exposed. The same rules apply to a repair: under Section R102.7.1, new shingles put on during a repair must meet the requirements for new work.
Michigan code rules for roof repairs
The chapter 9 sections that apply when shingles are replaced, from fasteners to flashing.
Code rules for repairsIf Your Roof Went on in Fall or Winter
- Step 1
Ask Whether It Was Hand Sealed
Ask the contractor directly, and ask them to put the answer in writing or on the invoice. If only part of the roof was hand sealed, such as the rakes and eaves, find out which parts.
- Step 2
Find Your Warranty Paperwork
Locate the manufacturer warranty and the installer's workmanship warranty and read the wind section of each. Note the installation date, because some terms depend on it.
- Step 3
Watch After the First Big Wind
After a windy day, walk the yard and look at each slope with binoculars. Look for tabs that sit up, shingle pieces on the ground and lines across tabs that were not there before. Photograph anything odd with the date.
- Step 4
Do Not Climb Up to Check
Cold shingles crack when stepped on or lifted, and a frosty or wet roof is a fall hazard. If you think tabs are loose, call the installer or a roofer.
- Step 5
Plan a Spring Look
After a few weeks of warm, sunny spring weather, have the roof checked, with attention to north and shaded slopes. A roofer can lift a few tabs carefully in mild weather to confirm the seal took, and hand seal any stragglers.
When Unsealed Shingles Become a Repair
Lifted tabs that are still intact are usually a small job: clean the strip if needed, check the nails, and hand seal them in the manufacturer's pattern. Creased, torn or missing shingles have to be replaced, and the courses around them checked, because the shingle next to a gap is the next one to go. If a whole roof never sealed because of how it was nailed, that is a bigger conversation than a few tabs.
When Stellar repairs wind damage in cold weather, the crew hand seals the repaired area rather than waiting on the factory strip. The pages below cover the warning signs and the repair in more detail.
Wind damage warning signs
What lifted, creased and missing shingles look like, and why shingles rated for high winds still come off.
Read about wind damageWind damage repair
How a wind repair is scoped, priced and done, including the seal and nailing check on the surrounding courses.
See wind damage repairMissing shingles
If tabs have already blown off, the deck and underlayment are exposed and the next rain matters.
Missing shingle repairWhat You See From the Ground, and What It Usually Means
| What you see | Likely condition | Will spring fix it? | Usual fix |
|---|---|---|---|
| Tabs lying flat, roof less than a season old | May be unsealed but undamaged | Usually, if the strip is clean and the nails are right | Spring check; hand seal any that did not bond |
| Tab edges sitting up or fluttering in wind | Unsealed and starting to work loose | Not reliably | Hand seal soon; check nails |
| A line or fold across a tab | Creased; the mat is broken at the fold | No | Replace the shingle |
| Bare patch or shingle pieces in the yard | Blown off | No | Replace shingles, check underlayment and neighbors |
| Loose or missing ridge caps | Caps unsealed or under-fastened | Not reliably | Reset, replace and hand seal caps |
A guide, not a diagnosis. Some conditions can only be confirmed up close by someone who knows how to handle cold shingles.
Roof Put on Late in the Year?
If you are seeing lifted or flapping tabs, or just want to know whether a fall install sealed, a free inspection will tell you what is loose, what is damaged and what can wait for spring.
Related Guides
Can a Roof Be Repaired in Winter?
What can and cannot be done below 40 degrees, and which winter repairs are temporary.
Learn MoreRoof Repair Warranties Explained
Craftsmanship versus manufacturer warranties, and what each one really covers.
Learn MoreRoof Wind Damage
How wind off Lake Michigan lifts shingles and what to look for after a storm.
Learn MoreWind Damage Roof Repair
Re-sealing, re-nailing and replacing wind-damaged shingles across West Michigan.
Learn MoreQuestions We Hear
Is it bad to put a new roof on in a Michigan winter?
Not automatically. Roofs go on in cold weather all the time. The extra work is handling stiff shingles without cracking them and hand sealing them, because the factory strip will not bond until warm, sunny weather returns. A winter install done to the manufacturer's cold-weather instructions can perform well. One done like a July install, with no hand sealing, is exposed to wind until spring and may fall outside the wind warranty.
What temperature do shingles need to seal?
Manufacturers do not publish one number. GAF says shingles need several warm, sunny days, and ARMA says it depends on slope, orientation and sun exposure. What matters is the temperature of the shingle surface, which in sun runs well above the air temperature. In Grand Rapids, normal daily highs fall below 50°F in November and do not return above it until April, so a late fall install often waits for spring.
Will my shingles seal on their own in the spring?
Most will, if the sealant strip is clean, the nails were driven flush in the right place, and the tab still lies flat. Shingles that were lifted or creased by wind over the winter, sit in heavy shade, or collected dust on the strip may never bond. That is why a quick check after a few warm spring weeks is worth doing on any roof installed late in the year.
Can too much roofing cement under shingles cause problems?
Yes. Both GAF and CertainTeed warn that excess cement can blister shingles, and GAF says it can soften the asphalt in underlayments and leak barriers so it drips and stains. Hand sealing uses small dabs in set spots, applied as a thin layer, not a bead along the whole edge. A roof smeared with cement is not a better-sealed roof.
Who pays if new shingles blow off before they sealed?
It depends on the paperwork. GAF's shingle warranty excludes wind damage that happens before sealing, and wind damage to cold-weather shingles that were not hand sealed. Your installer's workmanship warranty may or may not cover it, depending on its written terms. If a storm caused the loss, your homeowners policy may also apply, so check with your insurer before assuming either way.
What This Page Cites
- Timberline HDZ, UHDZ, AS II, CS, HDZ RS and RS+ Installation Instructions (RESTL622-0423), GAF (https://images.thdstatic.com/catalog/pdfImages/ce/ce744b21-6c3d-4c1e-9396-919c6ffa7fe8.pdf), accessed October 2026
- GAF Shingle and Accessory Limited Warranty (RESWT160L-0426), GAF (https://www.lowes.com/pdf/GAF_Shingles_and_Accessories_warranty.pdf), accessed October 2026
- Shingle Applicator's Manual, Chapter 12: Landmark Series, CertainTeed (https://www.ringsend.com/media/product-files/file/Landmark_Pro_Install.pdf), accessed October 2026
- Recommendations for Installation of Asphalt Roofing Shingles in Cold Weather, Asphalt Roofing Manufacturers Association (https://asphaltroofing.org/recommendations-for-installation-of-asphalt-roofing-shingles-in-cold-weather/), accessed October 2026
- ASTM D7158/D7158M, Standard Test Method for Wind Resistance of Asphalt Shingles (Uplift Force/Uplift Resistance Method), scope, ASTM International (https://store.astm.org/d7158_d7158m-20.html), accessed October 2026
- 2015 Michigan Residential Code, Chapter 9 Roof Assemblies, Sections R904.1, R905.1, R905.2.4.1 (Table R905.2.4.1) and R905.2.6, International Code Council (https://codes.iccsafe.org/content/MIRC2015P2/chapter-9-roof-assemblies), accessed October 2026
- 2015 Michigan Residential Code, Chapter 3 Building Planning, Table R301.2(1) and Section R301.2.1.4 Exposure category, International Code Council (https://codes.iccsafe.org/content/MIRC2015P2/chapter-3-building-planning), accessed October 2026
- 2015 Michigan Residential Code, Chapter 1 Scope and Administration, Section R102.7.1, International Code Council (https://codes.iccsafe.org/content/MIRC2015P2/chapter-1-scope-and-administration), accessed October 2026
- U.S. Climate Normals 1991 to 2020, monthly normals for Grand Rapids Gerald R. Ford International Airport (USW00094860), NOAA National Centers for Environmental Information (https://www.ncei.noaa.gov/data/normals-monthly/1991-2020/access/USW00094860.csv), accessed October 2026