4 Reasons Park City Homeowners Should Never Install A Second Layer Of Shingles
Heavy Mountain Snow Loads Can Overwhelm Your Roof
Park City averages more than 300 inches of snowfall a year, and that snow can turn to dense, water-logged weight in late-season storms. Even a single new layer of shingles adds 2–3 lbs per square foot; doubling up can exceed the design limits of many residential truss systems.
Weight compounds quickly. Two layers of shingles plus wet snow can push 20–25 lbs per square foot—enough to cause sagging or structural failure.
Snow-shedding becomes harder. Extra shingle thickness creates ledges where snow snarls instead of sliding, increasing load duration.
Building code risk. Summit County inspectors may flag homes whose roof dead load no longer matches the plans, forcing costly retrofits.
Ice Dams and Moisture Traps Multiply
Park City’s freeze-thaw cycles are relentless: temperatures swing 40 °F in a day. A second layer of shingles traps heat and moisture, setting the stage for ice dams and hidden leaks.
Ventilation suffers. Additional material narrows soffit-to-ridge airflow paths, letting attic humidity condense beneath the roof deck.
Uneven shingle surface. High nails and curled tabs from the original roof telegraph through the new layer, catching melting snow that refreezes at the eaves.
Water wicks sideways. Moisture blocked by the bottom course spreads laterally, soaking underlayment and insulation before you notice stains inside.
Hidden Damage Stays Hidden—and Gets Worse
Installing a “layover” sidesteps a full tear-off, but it also hides critical warning signs that Park City homeowners need to address before winter returns.
Deck rot goes undetected. Without stripping old shingles, you never see soft spots or mold in the sheathing, allowing decay to spread.
Nail holding power declines. Fasteners driven through two layers may not bite fully into compromised decking, leading to shingle blow-offs in alpine winds.
Manufacturer warranties voided. Most asphalt-shingle brands—including premium ice-shield lines—refuse coverage when installed over existing roofs.
Local Codes, Insurance, and Long-Term Costs Outweigh Short-Term Savings
While a layover seems cheaper up front, Park City’s building environment makes it an expensive gamble.
Code compliance hurdles. Utah Residential Code R908.3 generally prohibits more than two roof coverings, but Summit County’s high-snow-load amendments often require complete removal for any reroofing.
Insurance claims denied. Snow-load failures or interior leaks traced to double-layer roofs can void coverage for “improper maintenance.”
Future tear-off expenses double. When the second roof inevitably fails sooner, contractors must dispose of two layers—doubling labor, landfill fees, and project time.
Home resale challenges. Savvy Park City buyers and inspectors flag double-layer roofs as an immediate replacement cost, eroding negotiation leverage.
Bottom line
In a climate as demanding as Park City’s, the perceived savings of adding a second layer of asphalt shingles evaporate under the weight of heavier snow loads, ice-dam risks, hidden structural damage, and stricter local codes.
A full tear-off and properly ventilated, single-layer roofing system not only protects your home but preserves its long-term value—and your peace of mind—through every Wasatch winter.