Les Grumdahl Window & Siding | Windows Installation & Roofing in Duluth, MN 55804

Duluth's freeze-thaw cycles and heavy snow are tough on roofs. For roof valley leaks—a common issue where water channels meet—our certified installers use specialized flashing techniques and high-quality underlayment to create a watertight seal. To prevent shingle cracking from thermal expansion and contraction, we install GAF shingles with advanced sealing strips and proper attic ventilation to regulate temperature. Our thorough roof inspections identify these vulnerabilities so we can provide a repair or a full replacement built to handle our local climate.

It means our own local team manages your project from the initial estimate to the final cleanup. When you work with us for window installation or siding replacement, you'll communicate directly with our Duluth-based staff and craftspeople throughout the process. We handle all sales, measurements, product sourcing (like Marvin Infinity windows), and installation ourselves. This approach ensures quality control, timely communication, and accountability, as we don't subcontract the core work. It's how a family-owned business has operated here since 1947.

Yes. As a certified GAF lifetime roofing contractor, our roof installations come with strong manufacturer warranties that often include lifetime coverage on the shingles. For our siding and window projects, we provide limited lifetime warranties on most products and our installation work. These warranties are our promise of durability, which is especially important given Duluth's weather. We provide all warranty details in writing during your free estimate, so you know exactly what is covered for the long-term protection of your home.