Yes, you can replace a roof in winter in Wisconsin. GAF says its Timberline HDZ shingles can be installed year round, and Owens Corning and CertainTeed both publish cold-weather instructions. What changes is the procedure. Owens Corning draws the line at 40 degrees, air and roof surface both: at or below it, the adhesive strip may not activate until warmer weather arrives, so the perimeter shingles get hand sealed and every field shingle goes on with a gap of no more than a sixteenth of an inch where shingle ends meet.
In Eau Claire, 40 degrees is most of the problem. NOAA’s 1991 to 2020 normals for Chippewa Valley Regional Airport give January an average high of 23 degrees, with a daily high of 40 or better on fewer than two days all month. A winter roof here is a cold-weather roof, and it gets put on by the cold-weather rules.
Installing shingles in winter: what the cold changes
Asphalt shingles are held down by nails and a strip of thermal sealant that bonds each row to the one below. GAF’s instructions say the sealant needs sun and warm temperatures to do that, and that shingles which never see adequate surface heat, or whose sealant gets dirty, may never seal. So the makers substitute hand sealing. Owens Corning calls for four one-inch dabs of asphalt roofing cement under each perimeter shingle, two dabs under each tab on a 3-tab roof, and warns that too much cement blisters the shingle. GAF requires every shingle to be hand sealed through prolonged cold, with four quarter-sized dabs.
Cold also makes shingles brittle. GAF warns they break easily in cold weather and that heavier premium shingles can crack at sharp bends, and CertainTeed says shingles must be warm enough to form over hips, ridges, and valleys without cracking. The workarounds are practical. GAF says to store the bundles in a space heated above 70 degrees the day before, and CertainTeed’s manual passes along a contractor’s habit of riding the ridge caps in a truck cab with the heater running for 20 minutes before they are bent.
Ice and water membrane below 40 degrees
The underlayment is stricter than the shingles, and on a low-pitch Eau Claire roof it is the part the code cares about. Wisconsin’s dwelling code, SPS 321.28(4), requires ice dam protection on shingle roofs of 4:12 or less over heated space, in the form of sheet metal or a self-adhered membrane labeled to ASTM D1970. On a shingle roof it is nearly always the membrane, and a membrane only works if it sticks.
| Membrane | Minimum to apply |
|---|---|
| GAF StormGuard and WeatherWatch | 45 degrees air; below 40 air, the rolls themselves must be at least 45 |
| Owens Corning WeatherLock | 40 degrees, air and deck both |
| CertainTeed WinterGuard | Above 40 degrees |
| Grace Ice & Water Shield | 40 degrees, air, deck, and membrane |
CertainTeed allows WinterGuard to be nailed in colder weather but says plainly that nailing it cannot provide protection from ice dams. So the membrane waits for a day warm enough for the product being used. Only GAF’s allows colder air, and then only if the rolls were stored overnight at 55 degrees or better and are at least 45 when they go down.
How many winter days work in Eau Claire
From the same NOAA normals, the average number of days each month when the high reaches 40 degrees, with the average high and low in degrees:
| Month | Days reaching 40 | Average high | Average low |
|---|---|---|---|
| November | 15.6 | 42 | 25 |
| December | 4.4 | 29 | 13 |
| January | 1.8 | 23 | 6 |
| February | 4.5 | 28 | 9 |
| March | 16.7 | 41 | 21 |
November and March are workable roofing months with care, and the 40 degree days usually come in the middle of the day, after the frost burns off the deck. December through February average just under eleven such days combined. Shingle work still happens then, hand sealed and scheduled around the forecast, but it is slower, and the underlayment days are the scarce ones.
Metal roofs in winter
A metal roof has no sealant strip to wait on, which makes steel the easier roof to put on in January. The panels go on in the cold, but the membrane underneath still needs a day that meets its number; Owens Corning’s WeatherLock for metal roofs goes down at 40 degrees and rising. The smaller cold limits sit in the trim work: McElroy Metal’s installation guide says tape and tube sealants may stiffen and lose adhesion below 20 degrees and suggests keeping them heated until use. The metal roofing page covers the panel systems.
When a winter roof replacement makes sense
A roof that is leaking into the house, storm damage the insurer has already approved, or a sale that cannot wait for April all justify a winter job, and done to the makers’ cold-weather rules it is a sound roof. An active leak that needs a stopgap first is an emergency roof repair call. An old roof that is simply wearing out can wait for spring; book it in late winter, when lead times are shortest. The roof replacement page walks through the tear-off, the timeline, and the cost.