Roof replacement
A Twin Cities roof has to do something most roofs never do: hold back standing water at the eaves in February, carry a season of snow, and survive sixty degrees of temperature range every year. Replacing one properly means paying for the parts that handle winter, and those are exactly the parts a thin quote leaves out.
When replacement is the right call
Three signals, and they usually arrive together. Age: a covering past twenty winters here has earned an evaluation even if nothing has leaked. Scattered small failures: loose ridge caps, lifted courses, nail heads telegraphing through: the signature of thermal fatigue rather than any single event, and a sign the material has stopped holding itself together. And recurring ice at the eaves: if the same wall stains every February, the roof is only half the problem, and replacement day is the moment to fix the other half.
On the metro’s subdivision housing, the street is also a signal. Whole plats were roofed within months of each other, so when neighboring homes of the same vintage start turning over, a roof of that age is worth evaluating. And in a market with a six-month working season, choosing your own timing is worth more here than almost anywhere: the difference between a quote gathered in March and a call made in July is a different contractor, a different price and a different month.
What a complete quote includes
Tear-off and disposal: how many layers come off; code allows two, so a roof recovered once in the 1990s comes down to the deck this time. Decking, priced per sheet, because nobody knows how many sheets are soft until the covering is off, and on a roof that has been through two tear-offs, the boards have taken a lot of nails.
Ice barrier membrane at the eaves, with the run named in feet rather than left to “per code”: the minimum is a floor, and on a low pitch with a deep overhang, going further is cheap. Valley construction, open with metal sheds ice and debris far better than shingle woven over itself. New flashing rather than reused at every wall junction, and cut into the mortar at masonry rather than caulked to its face. And attic ventilation, balanced intake to exhaust, which in this climate decides whether the new roof reaches its rated life.
The spread between two honest quotes usually lives in three places: the decking allowance, the ice barrier and valley scope, and the ventilation line. Asking each bidder those three questions puts every number on the same footing.
The Minnesota factor
The working season is the shortest of any major market: asphalt shingles bond by warmth, so replacements run roughly May through October, and a crew willing to install in November is making a promise the material cannot keep. That compressed calendar is why quoting in late winter matters so much, the crews that will be working in June are booked by people who called in March.
The second factor is the freeze-thaw cycle, which works every fastener and sealant strip through thousands of movements in a covering’s life. The third is the attic, and it is the one most often left out of a quote: in a climate where escaping heat turns snow into standing water at the eaves, ventilation is not an accessory to the roof. It is part of it.
Questions that separate two quotes on the same house
- How many layers are on this roof, and who hauls them away?
- Two is the code maximum, and a third layer turns up often enough on postwar stock here that the answer can change the project before the material is even chosen. Tear-off weight also drives the dumpster line, so the two belong in one sentence.
- What does each replacement sheet of decking cost?
- Soft sheathing is invisible until the covering is off. A stated per-sheet rate turns that into a number agreed in advance, which matters more in a six-month season, because a mid-job disagreement costs days nobody has to spare.
- How far up the slope does the ice barrier membrane run, in feet?
- Ask for feet, not a yes. Code sets a minimum measured inward from the eave, and on a shallow pitch with a deep overhang the ice can build past where the minimum ends. Extending it while the deck is open costs very little compared with what it prevents.
- Are the valleys being built open with metal, or woven in shingle?
- An open valley lined with metal sheds ice and meltwater; a woven valley holds both against the shingle. Both are legitimate construction, but in this climate the choice deserves a reason rather than a habit.
- Is flashing being replaced at every wall junction, or reused and sealed?
- A winter here cycles every joint through freeze and thaw dozens of times, and sealant is what gives first. Reused flashing with a fresh bead is the shortcut that reappears as a stain in March, on a roof that is otherwise a year old.
- Is intake and exhaust being corrected, or carried over as they are?
- Both, balanced to each other. Ice at the eaves is a heat problem before it is a water problem: warm attic air melts snow on the field, the water refreezes over the cold overhang, and the dam forms. Ventilation is the correction, and replacement day is when it costs the least.
- 1 Ridge caps. Fatigued by an annual swing few other climates ask of a roof.
- 2 The field. Snow load and age together, not one or the other.
- 3 Valleys. Meltwater runs under the snowpack here, out of sight.
- 4 Flashing. The chimney, and where a lower roof meets a wall.
- 5 The vent boot. Cold makes the rubber brittle, then a thaw opens the crack.
- 6 Eaves and ice dams. Ice builds at the edge wherever attic heat is escaping.